fix build: Add a few includes, suppress some werrors

Not sure how this slipped through the cracks, but I'm guessing the build broke when we upgraded the cpp compilers (to clang 17 and gcc 13). * Include <cstdint> in a few places * Suppress -Wstringop-overflow in sparkd-gcc-release build * Change const char * param to explicit std::string for proper type deduction in call to 'std::make_tuple'. For some reason, the gcc build was failing with an array-bounds werror (changing the arg fixed it).
fix build: Remove version suffix from RuntimeIdentifiers in csprojs
2024-03-18 19:14:48 +00:00 · 2024-03-18 15:13:01 -04:00 · 2024-03-18 15:09:49 -04:00 · 2024-03-18 15:09:49 -04:00 · 2024-03-18 15:09:27 -04:00 · 2024-03-13 13:43:35 -05:00
202 changed files with 15396 additions and 3839 deletions
@@ -207,17 +207,23 @@ dotnet_naming_symbols.parameters.applicable_accessibilities = public,internal,pr
 dotnet_naming_symbols.private_symbols.applicable_kinds = property,method,field,event,delegate
 dotnet_naming_symbols.private_symbols.applicable_accessibilities = protected,private

+# local symbols
+dotnet_naming_symbols.local_symbols.applicable_kinds = local
+
+# parameter symbols
+dotnet_naming_symbols.parameter_symbols.applicable_kinds = parameter
+
 # Naming styles

-dotnet_naming_style.snake_case.required_prefix =
-dotnet_naming_style.snake_case.required_suffix =
-dotnet_naming_style.snake_case.word_separator = _
-dotnet_naming_style.snake_case.capitalization = all_lower
+dotnet_naming_style.pascal_case.required_prefix =
+dotnet_naming_style.pascal_case.required_suffix =
+dotnet_naming_style.pascal_case.word_separator =
+dotnet_naming_style.pascal_case.capitalization = pascal_case

-dotnet_naming_style.private_snake_case.required_prefix = _
-dotnet_naming_style.private_snake_case.required_suffix =
-dotnet_naming_style.private_snake_case.word_separator = _
-dotnet_naming_style.private_snake_case.capitalization = all_lower
+dotnet_naming_style.camel_case.required_prefix =
+dotnet_naming_style.camel_case.required_suffix =
+dotnet_naming_style.camel_case.word_separator =
+dotnet_naming_style.camel_case.capitalization = camel_case

 dotnet_naming_style.user_types.required_prefix =
 dotnet_naming_style.user_types.required_suffix =
@@ -229,6 +235,10 @@ dotnet_naming_style.interface.required_suffix =
 dotnet_naming_style.interface.word_separator =
 dotnet_naming_style.interface.capitalization = pascal_case

+dotnet_naming_style.local.capitalization = camel_case
+
+dotnet_naming_style.parameter.capitalization = camel_case
+
 # rules
 dotnet_naming_rule.user_types.symbols = user_types
 dotnet_naming_rule.user_types.style = user_types
@@ -238,14 +248,18 @@ dotnet_naming_rule.interfaces.symbols = interface
 dotnet_naming_rule.interfaces.style = interface_style
 dotnet_naming_rule.interfaces.severity = suggestion

-dotnet_naming_rule.public_members_snake_case.symbols = public_symbols
-dotnet_naming_rule.public_members_snake_case.style = snake_case
-dotnet_naming_rule.public_members_snake_case.severity = suggestion
+dotnet_naming_rule.public_members.symbols = public_symbols
+dotnet_naming_rule.public_members.style = pascal_case
+dotnet_naming_rule.public_members.severity = suggestion

-dotnet_naming_rule.private_members_snake_case.symbols = private_symbols
-dotnet_naming_rule.private_members_snake_case.style = private_snake_case
-dotnet_naming_rule.private_members_snake_case.severity = suggestion
+dotnet_naming_rule.private_members.symbols = private_symbols
+dotnet_naming_rule.private_members.style = camel_case
+dotnet_naming_rule.private_members.severity = suggestion

-dotnet_naming_rule.parameters.symbols = parameters
-dotnet_naming_rule.parameters.style = snake_case
+dotnet_naming_rule.variables_are_camel_case.severity = suggestion
+dotnet_naming_rule.variables_are_camel_case.symbols = local_symbols
+dotnet_naming_rule.variables_are_camel_case.style = local
+
+dotnet_naming_rule.parameters.symbols = parameter_symbols
+dotnet_naming_rule.parameters.style = parameter
 dotnet_naming_rule.parameters.severity = suggestion
@@ -29,8 +29,8 @@
        "CMAKE_TOOLCHAIN_FILE": "${sourceDir}/vcpkg/scripts/buildsystems/vcpkg.cmake",
        "EXTERNALS_ROOT": "${sourceDir}/externals/windows",
        "CONFIG_DEFAULTS_PATH": "config/profiles/default/*.conf",
-        "DOTNET_BINARY_DIR": "${sourceDir}/build/$<CONFIG>/bin/net7.0",
-        "DOTNET_WINDOWS_BINARY_DIR": "${sourceDir}/build/$<CONFIG>/bin/net7.0-windows"
+        "DOTNET_BINARY_DIR": "${sourceDir}/build/$<CONFIG>/bin/net8.0",
+        "DOTNET_WINDOWS_BINARY_DIR": "${sourceDir}/build/$<CONFIG>/bin/net8.0-windows"
      }
    },

@@ -143,7 +143,7 @@
      "cacheVariables": {
        "CMAKE_C_COMPILER": "gcc",
        "CMAKE_CXX_COMPILER": "g++",
-        "CMAKE_CXX_FLAGS_RELEASE": "-fPIC -Wall -pedantic -Wextra -Werror -Wno-missing-braces -Wno-ignored-qualifiers --std=c++20 -fdiagnostics-color -Wno-stringop-overread -Wno-maybe-uninitialized -fno-omit-frame-pointer -DNDEBUG -O3",
+        "CMAKE_CXX_FLAGS_RELEASE": "-fPIC -Wall -pedantic -Wextra -Werror -Wno-missing-braces -Wno-ignored-qualifiers -Wno-stringop-overflow --std=c++20 -fdiagnostics-color -Wno-stringop-overread -Wno-maybe-uninitialized -fno-omit-frame-pointer -DNDEBUG -O3",
        "CMAKE_INSTALL_PREFIX": "${sourceDir}/install/gcc/release/sparkd"
      }
    },
@@ -197,7 +197,7 @@
        "CMAKE_CXX_FLAGS_RELEASE": "-fPIC -Wall -pedantic -Wextra -Werror -Wno-missing-braces -Wno-ignored-qualifiers --std=c++20 -fdiagnostics-color -fno-omit-frame-pointer -DNDEBUG -O3",
        "CMAKE_INSTALL_PREFIX": "${sourceDir}/install/${presetName}",
        "CONFIG_DEFAULTS_PATH": "config/profiles/default/*.conf",
-        "DOTNET_BINARY_DIR": "${sourceDir}/build/$<CONFIG>/bin/net7.0"
+        "DOTNET_BINARY_DIR": "${sourceDir}/build/$<CONFIG>/bin/net8.0"
      }
    },

@@ -1,65 +1,74 @@
-FROM ubuntu:latest
+FROM ubuntu:22.04

 ARG DEBIAN_FRONTEND=noninteractive
-ENV TZ=America/New_York

-# light deps (should be quick to download/install)
-RUN apt-get update && apt-get install -y \
-    ca-certificates \
-    curl \
-    gnupg \
-    liblttng-ust-dev \
-    libpcap0.8-dev \
-    locales \
-    ninja-build \
-    software-properties-common \
-    sqlite3 \
-    tzdata
+# Note installations that take a while (more than 10s)

-# clang
-RUN apt-get update && apt-get install -y \
-    clang-13 \
-    clang-format-13 \
-    clangd-13 \
-    clang-15 \
-    clang-format-15 \
-    clangd-15
+RUN apt-get update
+RUN apt-get install -y ca-certificates
+RUN apt-get install -y ccache
+RUN apt-get install -y curl
+RUN apt-get install -y fish
+RUN apt-get install -y gdb
+# git-all: ~250s
+RUN apt-get install -y git-all
+RUN apt-get install -y gnupg
+# liblttng-ust-dev: ~30s
+RUN apt-get install -y liblttng-ust-dev
+RUN apt-get install -y libssh2-1-dev
+RUN apt-get install -y locales
+RUN apt-get install -y ninja-build
+# openssh-server: ~40s
+RUN apt-get install -y openssh-server
+RUN apt-get install -y pkg-config
+RUN apt-get install -y software-properties-common
+RUN apt-get install -y sudo
+RUN apt-get install -y tzdata
+RUN apt-get install -y vim
+RUN apt-get install -y zip

-# g++
-RUN apt-get update && apt-get install -y \
-    g++-11 \
-    g++-12
-
-# python
-RUN apt-get update && apt-get install -y \
+# Python: ~30s
+RUN apt-get install -y \
    python3-pip \
    python3-venv \
    && python3 -m pip install --upgrade pip

-# dotnet
-RUN apt-get update && apt-get install -y \
-    dotnet7
+# GCC
+ARG gcc_major=13
+RUN add-apt-repository ppa:ubuntu-toolchain-r/test \
+    && apt-get update \
+    && apt-get install -y g++-$gcc_major

-# ssh
-RUN apt-get update && apt-get install -y \
-    libssh2-1-dev \
-    openssh-server
+# Clang
+ARG clang_major=17
+RUN curl -fsSL https://apt.llvm.org/llvm-snapshot.gpg.key 2> /dev/null \
+    | gpg --dearmor - \
+    | tee /usr/share/keyrings/llvm-snapshot.gpg > /dev/null \
+    && echo "deb [signed-by=/usr/share/keyrings/llvm-snapshot.gpg] http://apt.llvm.org/$(lsb_release -cs)/ llvm-toolchain-$(lsb_release -cs)-$clang_major main" \
+    | tee -a "/etc/apt/sources.list.d/llvm.list" \
+    && apt-get update \
+    && apt-get install -y \
+    clang-$clang_major \
+    clang-format-$clang_major \
+    clangd-$clang_major

-# cmake
-RUN \
-    curl -fsSL https://apt.kitware.com/keys/kitware-archive-latest.asc 2> /dev/null \
+# CMake
+RUN curl -fsSL https://apt.kitware.com/keys/kitware-archive-latest.asc 2> /dev/null \
    | gpg --dearmor - \
    | tee /usr/share/keyrings/kitware-archive-keyring.gpg > /dev/null \
    && echo "deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ $(lsb_release -cs) main" \
    | tee /etc/apt/sources.list.d/kitware.list > /dev/null \
    && apt-get update \
-    && rm /usr/share/keyrings/kitware-archive-keyring.gpg \
-    && apt-get install -y kitware-archive-keyring \
-    && echo "deb [signed-by=/usr/share/keyrings/kitware-archive-keyring.gpg] https://apt.kitware.com/ubuntu/ $(lsb_release -cs)-rc main" \
-    | tee -a /etc/apt/sources.list.d/kitware.list >/dev/null \
    && apt-get install -y cmake

-# node
+# Dotnet
+RUN curl -fsSLO "https://packages.microsoft.com/config/ubuntu/$(lsb_release -rs)/packages-microsoft-prod.deb" \
+    && dpkg -i packages-microsoft-prod.deb \
+    && rm packages-microsoft-prod.deb \
+    && apt-get update \
+    && apt-get install -y dotnet-sdk-8.0
+
+# Node
 ARG node_major=18
 RUN mkdir -p /etc/apt/keyrings \
    && curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key \
@@ -69,60 +78,35 @@ RUN mkdir -p /etc/apt/keyrings \
    && apt-get update \
    && apt-get install -y nodejs

-# ccache is done here so that ccache sees clang++ installed, not clang-10
-RUN apt-get update && apt-get install -y \
-    ccache 
-
-# emumba (light deps)
+# Emumba deps
 RUN apt-get update && apt-get install -y \
    build-essential \
    doxygen \
-    python3-sphinx \
    graphviz \
    libgtest-dev \
    libssl-dev \
+    pkg-config \
+    python3-sphinx \
    rapidjson-dev \
-    zlib1g-dev \
-    pkg-config
+    zlib1g-dev

-# emumba (boost)
-RUN apt-get update && apt-get install -y \
-    libboost-filesystem-dev \
-    libboost-program-options-dev \
-    libboost-test-dev \
-    libboost-date-time-dev
-
-# dev utils
-RUN apt-get update && apt-get install -y \ 
-    fish \
-    git-all \
-    sudo \
-    vim \
-    wget
-
-# set up default executables (update-alternatives)
-RUN \
-    update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-13 100; \
-    update-alternatives --install /usr/bin/clang clang /usr/bin/clang-13 100; \
-    update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-13 100; \
-    update-alternatives --install /usr/bin/clangd clangd /usr/bin/clangd-13 100; \
-    update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-11 100; \
-    update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-11 100
+# Set up default executables (update-alternatives)
+RUN update-alternatives --install /usr/bin/clang clang /usr/bin/clang-$clang_major 100; \
+    update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-$clang_major 100; \
+    update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-$clang_major 100; \
+    update-alternatives --install /usr/bin/clangd clangd /usr/bin/clangd-$clang_major 100; \
+    update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-$gcc_major 100; \
+    update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-$gcc_major 100

 # Add compiler symlinks for ccache 
-RUN \
-    ln -s /usr/bin/ccache /usr/local/bin/clang; \
+RUN ln -s /usr/bin/ccache /usr/local/bin/clang; \
    ln -s /usr/bin/ccache /usr/local/bin/clang++; \
-    ln -s /usr/bin/ccache /usr/local/bin/clang-13; \
-    ln -s /usr/bin/ccache /usr/local/bin/clang++-13; \
-    ln -s /usr/bin/ccache /usr/local/bin/clang-15; \
-    ln -s /usr/bin/ccache /usr/local/bin/clang++-15; \
+    ln -s /usr/bin/ccache /usr/local/bin/clang-$clang_major; \
+    ln -s /usr/bin/ccache /usr/local/bin/clang++-$clang_major; \
    ln -s /usr/bin/ccache /usr/local/bin/gcc; \
    ln -s /usr/bin/ccache /usr/local/bin/g++; \
-    ln -s /usr/bin/ccache /usr/local/bin/gcc-11; \
-    ln -s /usr/bin/ccache /usr/local/bin/g++-11; \
-    ln -s /usr/bin/ccache /usr/local/bin/gcc-12; \
-    ln -s /usr/bin/ccache /usr/local/bin/g++-12
+    ln -s /usr/bin/ccache /usr/local/bin/gcc-$gcc_major; \
+    ln -s /usr/bin/ccache /usr/local/bin/g++-$gcc_major

 RUN locale-gen en_US.UTF-8

@@ -130,8 +114,7 @@ ARG docker_user="bts"
 ARG docker_uid="1000"
 ARG docker_pass="bts"

-RUN \
-    groupadd -g "$docker_uid" "$docker_user" \
+RUN groupadd -g "$docker_uid" "$docker_user" \
    && useradd \
    -m \
    -u "$docker_uid" \
@@ -1,6 +0,0 @@
-{
-  "sdk": {
-    "version": "6.0.200",
-    "rollForward": "latestMajor"
-  }
-}
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0-windows</TargetFramework>
+    <TargetFramework>net8.0-windows</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <UseWindowsForms>true</UseWindowsForms>
@@ -42,7 +42,6 @@ OpenParenthesis          \(
 CloseParenthesis         \)
 Comma                    ,
 Negate                   '!'
-MapsTo                   ':'
 IsOfType                 '/'

 %%
@@ -98,10 +97,6 @@ IsOfType                 '/'
   return (int)Token.NEGATE;
 }

-{MapsTo} {
-   return (int)Token.MAPS_TO;
-}
-
 {Equal} {
   return (int)Token.EQUAL;
 }
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\client\spark_websocket\spark_websocket.csproj" />
+    <ProjectReference Include="..\DataStreamExpressions\DataStreamExpressions.csproj" />
+    <ProjectReference Include="..\..\client\spark_core\spark_core.csproj" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,9 @@
+namespace Bts.DataStream.Websocket;
+
+class ClientSubscription(WebsocketClientID id, SubscriptionParams @params, IDisposable dispose) : IDisposable {
+   public SubscriptionParams Params => @params;
+   public WebsocketClientID Id => id;
+
+   public void Dispose() =>
+      dispose.Dispose();
+}
@@ -0,0 +1,301 @@
+namespace Bts.DataStream.Websocket;
+
+using BCG;
+
+using bts;
+using bts.api.core;
+using bts.collections;
+using bts.websocket_core.json_rpc;
+
+using Bts.DataStreamExpressions;
+
+using mbts.utils;
+
+using Spark.Core.Disposables;
+using Spark.Core.Json;
+
+using System.Buffers;
+using System.Reactive.Subjects;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Nodes;
+
+/// <summary>
+/// Represents an I/O model (<see cref="ISubject{TSource, TResult}"/>), that accepts websocket
+/// requests (from clients) as input, and emits data/notifications (to clients) as output.
+/// This class's chief role is managing data subscriptions to sparkd on the clients' behalf.
+/// </summary>
+public class DataSync(JsonSerializerOptions? serializerOpts = null) :
+   ISubject<WebsocketConnectionUpdate, IEnumerable<WebsocketOutgoingMessage>> {
+   protected readonly object lockObj = new();
+   readonly JsonSerializerOptions serializerOpts = serializerOpts ?? JsonSerializerOptions.Default;
+   readonly Dictionary<WebsocketClientID, List<ClientSubscription>> clients = [];
+
+   event Action<IEnumerable<WebsocketOutgoingMessage>>? requestSend;
+
+   public void OnCompleted() =>
+      Log.Api.info("DataSync incoming request stream has completed.");
+
+   public void OnError(Exception error) =>
+      Log.Api.error($"DataSync error: {error}");
+
+   public void OnNext(WebsocketConnectionUpdate value) {
+      switch (value.Type) {
+         case WebsocketConnectionUpdateType.IncomingMessage:
+            onIncomingMessage(value.IncomingMessage);
+            break;
+         case WebsocketConnectionUpdateType.Connect:
+            onConnect(value.Connect);
+            break;
+         case WebsocketConnectionUpdateType.Disconnect:
+            onDisconnect(value.Disconnect);
+            break;
+         default:
+            Log.assert(false, $"Unexpected WebsocketConnectionUpdate type: {value.Type}");
+            break;
+      }
+   }
+
+   public IDisposable Subscribe(IObserver<IEnumerable<WebsocketOutgoingMessage>> observer) {
+      lock (lockObj) {
+         requestSend += observer.OnNext;
+         return Disposable.Create(Dispose);
+      }
+      void Dispose() {
+         lock (lockObj) {
+            requestSend -= observer.OnNext;
+         }
+      }
+   }
+
+   static JsonRpcId? extractRpcId(string messageBody) {
+      try {
+         return JsonNode.Parse(messageBody)
+            ?.AsObject()
+            ?.GetValueOrDefault("id")
+            ?.Deserialize<JsonRpcId>();
+      } catch {
+         return null;
+      }
+   }
+
+   static string getRpcNotification(DataPacket dp) {
+      using (var buffer = new MemoryStream())
+      using (var writer = new Utf8JsonWriter(buffer))
+      using (writer.WriteObject()) {
+         writer.WriteString("method", "subscription");
+         using (writer.WriteObject("params")) {
+            writer.Write("tableName", dp.schema.tableName);
+            writer.Write("columns", dp.schema.columnInfo);
+            var cellJsonFactories = dp.schema.columnInfo.Select(getCellJsonFactory).ToList();
+            using (writer.WriteArray("added")) {
+               foreach (IBlueRow row in (dp.addedRows?.Cast<IBlueRow>()).empty_if_null()) {
+                  using (writer.WriteObject()) {
+                     for (int i = 0; i < cellJsonFactories.Count; i++) {
+                        writer.Write(dp.schema.columnInfo[i].colName, cellJsonFactories[i](row));
+                     }
+                  }
+               }
+            }
+            using (writer.WriteArray("deleted")) {
+               foreach (IBlueRow row in (dp.deletedRows?.Cast<IBlueRow>()).empty_if_null()) {
+                  using (writer.WriteObject()) {
+                     for (int i = 0; i < cellJsonFactories.Count; i++) {
+                        writer.Write(dp.schema.columnInfo[i].colName, cellJsonFactories[i](row));
+                     }
+                  }
+               }
+            }
+         }
+         writer.WriteString("jsonrpc", "2.0");
+         writer.Flush();
+         return Encoding.UTF8.GetString(buffer.ToArray());
+      }
+   }
+
+   static Func<IBlueRow, JsonNode?> getCellJsonFactory(ColumnInfo colInfo) {
+      var t = colInfo.colType;
+      if (t == typeof(int)) {
+         return NullCheckWrapper(v => (int)v);
+      }
+      if (t == typeof(uint)) {
+         return NullCheckWrapper(v => (uint)v);
+      }
+      if (t == typeof(long)) {
+         return NullCheckWrapper(v => (long)v);
+      }
+      if (t == typeof(ulong)) {
+         return NullCheckWrapper(v => (ulong)v);
+      }
+      if (t == typeof(short)) {
+         return NullCheckWrapper(v => (short)v);
+      }
+      if (t == typeof(ushort)) {
+         return NullCheckWrapper(v => (ushort)v);
+      }
+      if (t == typeof(double)) {
+         return NullCheckWrapper(v => (double)v);
+      }
+      if (t == typeof(float)) {
+         return NullCheckWrapper(v => (float)v);
+      }
+      if (t == typeof(bool)) {
+         return NullCheckWrapper(v => (bool)v);
+      }
+      return NullCheckWrapper(v => (string)v);
+
+      Func<IBlueRow, JsonNode?> NullCheckWrapper(Func<object, JsonNode> toJson) =>
+         r => {
+            var obj = r[colInfo.colNo];
+            if (obj is null) {
+               return null;
+            }
+            return toJson(obj);
+         };
+   }
+
+   void onConnect(WebsocketConnectNotification notification) {
+      var id = notification.Id;
+      lock (lockObj) {
+         clients.Add(id, []);
+      }
+      Log.Api.info($"DataStreamWebsocketDataSync client connected. clientId: {notification.Id}");
+      if (notification.Message is not null) {
+         onIncomingMessage(notification.Message);
+      }
+   }
+
+   void onDisconnect(WebsocketDisconnectNotification notification) {
+      Log.Api.warn($"DataStreamWebsocketDataSync client disconnected. clientId: {notification.Id}");
+      unsubscribeAll(notification.Id);
+      clients.Remove(notification.Id);
+   }
+
+   void onIncomingMessage(WebsocketIncomingMessage message) {
+      var id = message.sender_client_id;
+      if (!JsonRpcRequest.TryDeserialize(message, out var req, out var err)) {
+         onBadRequest(message, err);
+         return;
+      }
+      switch (req.Method!.ToLower()) {
+         case "subscribe":
+            subscribe(id, req);
+            break;
+         case "publish":
+            Log.Api.error("DataStreamWebsocket api 'publish' not implemented.");
+            // TODO
+            break;
+         case "unsubscribe":
+            unsubscribe(id, req);
+            break;
+         case "unsubscribe_all":
+            unsubscribeAll(id);
+            break;
+         default:
+            Log.Api.error($"Received request of unknown type: {req}");
+            break;
+      }
+   }
+
+   void sendResponse<T>(WebsocketClientID id, JsonRpcId rpcId, T rpcParams) {
+      var rpcRes = JsonRpcResponse.Create(rpcId, rpcParams);
+      var rpcResStr = JsonSerializer.Serialize(rpcRes, serializerOpts);
+      send([new(id, rpcResStr)]);
+   }
+
+   void sendError<T>(WebsocketClientID id, JsonRpcId rpcId, JsonRpcError<T> error) {
+      var rpcRes = JsonRpcResponse.CreateError(rpcId, error);
+      var rpcResStr = JsonSerializer.Serialize(rpcRes, serializerOpts);
+      send([new(id, rpcResStr)]);
+   }
+
+   bool send(IEnumerable<WebsocketOutgoingMessage> messages) {
+      lock (lockObj) {
+         if (requestSend is null) {
+            Log.Api.warn(
+               $"Unable to send message(s) because '{nameof(requestSend)}' handler is null");
+            return false;
+         }
+         requestSend(messages);
+         return true;
+      }
+   }
+
+   void subscribe(WebsocketClientID id, JsonRpcRequest<JsonObject?> req) {
+      var subParams = req.Params!.Deserialize<SubscriptionParams>()!;
+      var exp = DataStreamExpressionsInterpreter.Evaluate(subParams.Query!);
+      var stream = exp.getView(new Dictionary<string, StatementExpression>(0));
+      var sub = new ClientSubscription(id, subParams, Disposable.Create(Dispose));
+      lock (lockObj) {
+         clients[id].Add(sub);
+         sendResponse(id, req.Id!.Value, req.Params);
+         stream.onChange += OnChange;
+      }
+
+      void OnChange(object? newValue) {
+         var dp = ExceptionAssert.of_type<DataPacket>(newValue);
+         var notif = getRpcNotification(dp);
+         send([new(id, notif)]);
+      }
+
+      void Dispose() =>
+         stream.onChange -= OnChange;
+   }
+
+   void unsubscribe(WebsocketClientID id, JsonRpcRequest<JsonObject?> req) {
+      var subParams = req.Params!.Deserialize<SubscriptionParams>();
+      var subParamsStr = JsonSerializer.Serialize(subParams, serializerOpts);
+      // Minimize amount of code inside lock (just need it to find/remove the subscription)
+      List<ClientSubscription>? subs = null;
+      ClientSubscription? sub = null;
+      lock (lockObj) {
+         subs = clients.GetValueOrDefault(id);
+         subs?.TryRemoveFirst(s => s!.Params.Equals(subParams), out sub);
+      }
+      if (subs is null) {
+         // Didn't find client (log/throw).
+         var msg = $"Unable to unsubscribe: did not find client. Id: {id}.\nParams:\n{subParamsStr}";
+         Log.Api.error(msg);
+         throw new Exception(msg);
+      }
+      if (sub is null) {
+         // Found client, but didn't find subscription (log/throw).
+         var msg = $"Unable to unsubscribe: did not find the specified subscription. " +
+            $"Id: {id}. Request:\n{subParams}";
+         Log.Api.error(msg);
+         throw new Exception(msg);
+      }
+      // Found client and subscription (dispose/remove subscription).
+      Log.Api.info($"Unsubscribing client. Id: {id}.\nParams:\n{subParamsStr}");
+      sub.Dispose();
+   }
+
+   void unsubscribeAll(WebsocketClientID id) {
+      lock (lockObj) {
+         if (!clients.TryGetValue(id, out var subs)) {
+            throw new Exception(
+               $"Unable to unsubscribe: did not find client with id {id}");
+         }
+         subs.DisposeAll();
+         subs.Clear();
+      }
+   }
+
+   void onBadRequest(WebsocketIncomingMessage req, string? errorMsg) {
+      var rpcId = extractRpcId(req.message_body);
+      var logMsg = $"Recieved invalid request:\n{req.message_body}";
+      if (errorMsg is not null) {
+         logMsg += $"\n\n**Exception**\n{errorMsg}";
+      }
+      Log.Api.error(logMsg);
+      if (rpcId is null) {
+         return;
+      }
+      // Send error back to client
+      var rpcErr = JsonRpcError.Create(
+         (long)JsonRpcErrorCode.InvalidRequest,
+         $"Received invalid request: {errorMsg ?? "unknown error"}",
+         req.message_body);
+      sendError(req.sender_client_id, rpcId.Value, rpcErr);
+   }
+}
@@ -0,0 +1,34 @@
+namespace Bts.DataStream.Websocket;
+
+using Newtonsoft.Json.Linq;
+
+using System.Diagnostics.CodeAnalysis;
+
+public static class JObjectExtensions {
+   public static bool TryParse<T>(
+      this JObject filter, string key, [MaybeNull] out T obj, [NotNullWhen(false)] out string? error) {
+      obj = default;
+      var value = filter.GetValueOrDefault(key)?.ToString();
+      if (value == null) {
+         error = $"{key} not present";
+         return true;
+      }
+      return WebsocketJsonParsers.TryParse(value, key, out obj, out error);
+   }
+
+   public static bool TryParse<T>(
+     this JObject filter, string key, out T result, [NotNullWhen(false)] out string? error, T defaultValue) {
+      var value = filter.GetValueOrDefault(key)?.ToString();
+      if (value == null) {
+         result = defaultValue;
+         error = $"{key} not present";
+         return true;
+      }
+      if (WebsocketJsonParsers.TryParse<T>(value, key, out var maybeRes, out error)) {
+         result = maybeRes ?? defaultValue;
+         return true;
+      }
+      result = defaultValue;
+      return false;
+   }
+}
@@ -0,0 +1,48 @@
+namespace Bts.DataStream.Websocket;
+
+using Spark.Core;
+
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+class MultilineStringJsonConverter : JsonConverter<string> {
+   public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+      if (typeToConvert != typeof(string)) {
+         throw new ArgumentException($"Unable to parse {typeToConvert}", nameof(typeToConvert));
+      }
+      return reader.TokenType switch {
+         JsonTokenType.String => StringImpl(ref reader),
+         JsonTokenType.StartArray => ArrayImpl(ref reader),
+         _ => throw new ArgumentException(
+            $"Unable to parse {typeof(SubscriptionParams)} from {reader.TokenType}"),
+      };
+
+      static string? StringImpl(ref Utf8JsonReader reader) =>
+         new(reader.GetString()!);
+
+      static string? ArrayImpl(ref Utf8JsonReader reader) {
+         var lines = new List<string>(2);
+         while (reader.Read()) {
+            switch (reader.TokenType) {
+               case JsonTokenType.String:
+                  lines.Add(reader.GetString()!);
+                  break;
+               case JsonTokenType.EndArray:
+                  return string.Join("\n", lines);
+            }
+         }
+         throw new JsonException(
+            $"Failed to parse {typeof(SubscriptionParams)} (did not reach end of array)");
+      }
+   }
+
+   public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options) {
+      var lines = value.Split("\n");
+      if (lines.Length < 2) {
+         writer.WriteRawValue(value);
+         return;
+      }
+      writer.WriteRawValue($"[{", ".join(lines)}]");
+   }
+}
@@ -0,0 +1,8 @@
+namespace Bts.DataStream.Websocket;
+
+public enum RequestType {
+   Unspecified,
+   Subscribe,
+   Unsubscribe,
+   UnsubscribeAll,
+}
@@ -0,0 +1,25 @@
+namespace Bts.DataStream.Websocket;
+
+using bts;
+
+using Google.Protobuf;
+
+using System.Text.Json;
+
+public static class Session {
+   static int sessionIdCounter;
+
+   public static async Task Start(
+      WebsocketServerConfig config, JsonSerializerOptions? opts) {
+      opts ??= JsonSerializerOptions.Default;
+      var sessionId = Interlocked.Increment(ref sessionIdCounter);
+      var gateway = new WebsocketClient(config);
+      var sync = new DataSync(opts);
+      using (gateway.Subscribe(sync))
+      using (sync.Subscribe(gateway)) {
+         Log.Api.info($"Starting DataStream Websocket Session {sessionId}");
+         Log.Api.info($"DataStream Websocket Session {sessionId} config:\n{JsonFormatter.Default.Format(config)}");
+         await gateway.ConnectAsync();
+      }
+   }
+}
@@ -0,0 +1,112 @@
+namespace Bts.DataStream.Websocket;
+
+using bts.utils;
+
+using Spark.Core;
+using Spark.Core.Json;
+
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+public class SubscriptionParams(string? query = null) : IEquatable<SubscriptionParams> {
+   static class PropNames {
+      public const string QUERY = "query";
+   }
+
+   // Serializer supports plain string, or an array of lines for convenience
+   [MaybeNull]
+   [JsonPropertyName(PropNames.QUERY)]
+   [JsonConverter(typeof(MultilineStringJsonConverter))]
+   public string? Query { get; set; } = query;
+
+   public bool Equals(SubscriptionParams? other) =>
+      other is not null &&
+      // Not the most elegant equals impl, but it'll work
+      Query.safe_equals(other.Query, (a, b) => a?.ToString() == b?.ToString());
+
+   class SubscriptionParamsConverter : JsonConverter<SubscriptionParams> {
+      public override bool CanConvert(Type typeToConvert) =>
+         typeToConvert == typeof(SubscriptionParams);
+
+      public override SubscriptionParams Read(
+         ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+         if (typeToConvert != typeof(SubscriptionParams)) {
+            throw new ArgumentException($"Unable to parse {typeToConvert}", nameof(typeToConvert));
+         }
+         return read(ref reader);
+      }
+
+      static SubscriptionParams read(ref Utf8JsonReader reader) {
+         return reader.TokenType switch {
+            JsonTokenType.String => StringImpl(ref reader),
+            JsonTokenType.StartArray => ArrayImpl(ref reader),
+            JsonTokenType.StartObject => ObjectImpl(ref reader),
+            _ => throw new ArgumentException(
+               $"Unable to parse {typeof(SubscriptionParams)} from {reader.TokenType}"),
+         };
+
+         static SubscriptionParams StringImpl(ref Utf8JsonReader reader) =>
+            new(reader.GetString()!);
+
+         static SubscriptionParams ArrayImpl(ref Utf8JsonReader reader) {
+            var lines = new List<string>(2);
+            while (reader.Read()) {
+               switch (reader.TokenType) {
+                  case JsonTokenType.String:
+                     lines.Add(reader.GetString()!);
+                     break;
+                  case JsonTokenType.EndArray:
+                     return new("\n".join(lines));
+               }
+            }
+            throw new JsonException(
+               $"Failed to parse {typeof(SubscriptionParams)} (did not reach end of array)");
+         }
+
+         static SubscriptionParams ObjectImpl(ref Utf8JsonReader reader) {
+            var lines = new List<string>(2);
+            while (reader.Read()) {
+               switch (reader.TokenType) {
+                  case JsonTokenType.PropertyName:
+                     var propName = reader.GetString()!;
+                     if (propName == PropNames.QUERY) {
+                        switch (reader.TokenType) {
+                           case JsonTokenType.StartArray:
+                              return ArrayImpl(ref reader);
+                           case JsonTokenType.String:
+                              return StringImpl(ref reader);
+                        }
+                     }
+                     break;
+                  case JsonTokenType.String:
+                     lines.Add(reader.GetString()!);
+                     break;
+                  case JsonTokenType.EndArray:
+                     return new("\n".join(lines));
+               }
+            }
+            throw new JsonException(
+               $"Failed to parse {typeof(SubscriptionParams)} (did not reach end of array)");
+         }
+      }
+
+      public override void Write(
+         Utf8JsonWriter writer, SubscriptionParams value, JsonSerializerOptions options) {
+         var q = value.Query;
+         var lines = q?.Split("\n");
+         if (lines is null || lines.Length < 2) {
+            writer.WriteString(PropNames.QUERY, value.Query);
+            return;
+         }
+         writer.WriteArray(PropNames.QUERY, lines);
+      }
+   }
+
+   public override bool Equals(object? obj) =>
+      Equals(obj as SubscriptionParams);
+
+   public override int GetHashCode() =>
+      Query?.Length ?? typeof(SubscriptionParams).GetHashCode();
+}
@@ -0,0 +1,5 @@
+global using bts.websocket_core;
+
+global using System;
+
+global using System.Collections.Immutable;
@@ -0,0 +1,41 @@
+#nullable enable
+using BCG;
+
+using Spark.Core.Json;
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Bts.DataStreamCore;
+
+class ViewStreamUpdate {
+   [JsonPropertyName("tableName")]
+   public string? TableName { get; set; }
+
+   [JsonPropertyName("columns")]
+   public List<ColumnInfo>? Columns { get; set; }
+
+   [JsonPropertyName("addedRows")]
+   public List<Dictionary<string, object?>>? AddedRows { get; set; }
+
+   [JsonPropertyName("deletedRows")]
+   public List<Dictionary<string, object?>>? DeletedRows { get; set; }
+
+   public DataPacket ToDataPacket(BlueTable state, bool applyChanges = true) {
+      var schema = new BlueTableSchema([.. Columns!], TableName);
+      var addedRowsTable = new BlueTable(schema);
+      var deletedRowsTable = new BlueTable(schema);
+      if (applyChanges) {
+         state.deleteRows(deletedRowsTable);
+         state.addRows(addedRowsTable);
+      }
+      return new(state, addedRowsTable, deletedRowsTable);
+   }
+
+   public static string ToJson() {
+      return "";
+   }
+}
@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="System.CommandLine" Version="2.0.0-beta4.22272.1" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Bts.DataStream.Websocket\Bts.DataStream.Websocket.csproj" />
+  </ItemGroup>
+
+</Project>
@@ -0,0 +1,7 @@
+{
+  "host": "localhost",
+  "port": 8080,
+  "scheme": "ws",
+  "default_end_point": "/",
+  "keep_alive_interval_secs": 1
+}
@@ -0,0 +1,76 @@
+using bts.api.core;
+
+using Bts.DataStream.Websocket;
+
+using Google.Protobuf;
+
+using System.CommandLine.Parsing;
+using System.Text.Json;
+
+static WebsocketServerConfig readConfigFile(string path) {
+   using var fs = File.OpenRead(path);
+   using var sr = new StreamReader(fs);
+   return JsonParser.Default.Parse<WebsocketServerConfig>(sr);
+}
+
+static WebsocketServerConfig? readConfigArg(ArgumentResult result) {
+   var path = result.Tokens.Select(t => t.Value).FirstOrDefault() ?? string.Empty;
+   return readConfigFile(path);
+}
+
+static WebsocketServerConfig getDefaultConfig() {
+   const string defaultCfgPath = "DataStreamWebsocketServer.conf";
+   if (File.Exists(defaultCfgPath)) {
+      return readConfigFile(defaultCfgPath);
+   }
+   return new() {
+      Scheme = "http",
+      Host = "localhost",
+      Port = 8080,
+      DefaultEndPoint = "/",
+      KeepAliveIntervalSecs = 1
+   };
+}
+   
+static async Task run(
+   WebsocketServerConfig? wssConfig, string user, string password, string? sparkdConfigSource) {
+   var opts = new JsonSerializerOptions(JsonSerializerDefaults.Web);
+   wssConfig ??= getDefaultConfig();
+   Console.WriteLine("Starting DataStreamWebsocketServer...");
+   var serviceCtx = ServiceContext.create(sparkdConfigSource);
+   await serviceCtx.login(user, password);
+   await Session.Start(wssConfig, opts);
+   // if (sparkdConfigSource is not null && sparkdConfigSource.Length > 9999) {
+   // } else {
+   //    await ChatGptSession.Start();
+   // }
+}
+
+var userOpt = new Option<string>("--user", () => "bts");
+var passOpt = new Option<string>("--password", () => string.Empty);
+var sparkdConfigSourceOpt = new Option<string>(
+   "--sparkd", description: "The sparkd config server url");
+// var bling = new ParseArgument<WebsocketServerConfig?>(parseWsConfig);
+
+// WebsocketServerConfig? parseWsConfig(ArgumentResult result) {
+//    Token t;
+//    TokenType tt;
+//    Symbol s;
+//    throw new NotImplementedException();
+// }
+
+var configOpt = new Option<WebsocketServerConfig?>(
+   "--config", readConfigArg, description: "WebsocketServerConfig file path");
+configOpt.SetDefaultValue(new());
+var rootCommand = new RootCommand("Starts a DataStream Websocket Server");
+rootCommand.AddOption(configOpt);
+rootCommand.AddOption(userOpt);
+rootCommand.AddOption(passOpt);
+rootCommand.SetHandler(run, configOpt, userOpt, passOpt, sparkdConfigSourceOpt);
+
+try {
+   return await rootCommand.InvokeAsync(args);
+} catch (Exception ex) {
+   Console.WriteLine($"Error: {ex}");
+}
+return 1;
@@ -0,0 +1,6 @@
+global using bts.websocket_core;
+global using bts.websocket_core.json_rpc;
+
+global using System.CommandLine;
+
+global using System.Collections.Immutable;
@@ -0,0 +1,20 @@
+module.exports = {
+  root: true,
+  env: { browser: true, es2020: true },
+  extends: [
+    'eslint:recommended',
+    'plugin:react/recommended',
+    'plugin:react/jsx-runtime',
+    'plugin:react-hooks/recommended',
+  ],
+  ignorePatterns: ['dist', '.eslintrc.cjs'],
+  parserOptions: { ecmaVersion: 'latest', sourceType: 'module' },
+  settings: { react: { version: '18.2' } },
+  plugins: ['react-refresh'],
+  rules: {
+    'react-refresh/only-export-components': [
+      'warn',
+      { allowConstantExport: true },
+    ],
+  },
+}
@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
@@ -0,0 +1,11 @@
+<Project Sdk="Microsoft.VisualStudio.JavaScript.Sdk/0.5.128-alpha">
+  <PropertyGroup>
+    <StartupCommand>npm run dev</StartupCommand>
+    <JavaScriptTestRoot>src\</JavaScriptTestRoot>
+    <JavaScriptTestFramework>Jest</JavaScriptTestFramework>
+    <!-- Allows the build (or compile) script located on package.json to run on Build -->
+    <ShouldRunBuildScript>false</ShouldRunBuildScript>
+    <!-- Folder where production build objects will be placed -->
+    <PublishAssetsDirectory>$(MSBuildProjectDirectory)\dist</PublishAssetsDirectory>
+  </PropertyGroup>
+</Project>
@@ -0,0 +1,8 @@
+# React + Vite
+
+This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
+
+Currently, two official plugins are available:
+
+- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react/README.md) uses [Babel](https://babeljs.io/) for Fast Refresh
+- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react-swc) uses [SWC](https://swc.rs/) for Fast Refresh
@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Vite + React</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.jsx"></script>
+  </body>
+</html>
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <clear />
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+  </packageSources>
+  <disabledPackageSources>
+    <clear />
+  </disabledPackageSources>
+</configuration>
@@ -0,0 +1,27 @@
+{
+  "name": "bts.datastreamwebapp.client",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "lint": "eslint . --ext js,jsx --report-unused-disable-directives --max-warnings 0",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "react-use-websocket": "^4.5.0"
+  },
+  "devDependencies": {
+    "@types/react": "^18.2.43",
+    "@types/react-dom": "^18.2.17",
+    "@vitejs/plugin-react": "^4.2.1",
+    "eslint": "^8.55.0",
+    "eslint-plugin-react": "^7.33.2",
+    "eslint-plugin-react-hooks": "^4.6.0",
+    "eslint-plugin-react-refresh": "^0.4.5",
+    "vite": "^5.0.8"
+  }
+}
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" class="iconify iconify--logos" width="31.88" height="32" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 257"><defs><linearGradient id="IconifyId1813088fe1fbc01fb466" x1="-.828%" x2="57.636%" y1="7.652%" y2="78.411%"><stop offset="0%" stop-color="#41D1FF"></stop><stop offset="100%" stop-color="#BD34FE"></stop></linearGradient><linearGradient id="IconifyId1813088fe1fbc01fb467" x1="43.376%" x2="50.316%" y1="2.242%" y2="89.03%"><stop offset="0%" stop-color="#FFEA83"></stop><stop offset="8.333%" stop-color="#FFDD35"></stop><stop offset="100%" stop-color="#FFA800"></stop></linearGradient></defs><path fill="url(#IconifyId1813088fe1fbc01fb466)" d="M255.153 37.938L134.897 252.976c-2.483 4.44-8.862 4.466-11.382.048L.875 37.958c-2.746-4.814 1.371-10.646 6.827-9.67l120.385 21.517a6.537 6.537 0 0 0 2.322-.004l117.867-21.483c5.438-.991 9.574 4.796 6.877 9.62Z"></path><path fill="url(#IconifyId1813088fe1fbc01fb467)" d="M185.432.063L96.44 17.501a3.268 3.268 0 0 0-2.634 3.014l-5.474 92.456a3.268 3.268 0 0 0 3.997 3.378l24.777-5.718c2.318-.535 4.413 1.507 3.936 3.838l-7.361 36.047c-.495 2.426 1.782 4.5 4.151 3.78l15.304-4.649c2.372-.72 4.652 1.36 4.15 3.788l-11.698 56.621c-.732 3.542 3.979 5.473 5.943 2.437l1.313-2.028l72.516-144.72c1.215-2.423-.88-5.186-3.54-4.672l-25.505 4.922c-2.396.462-4.435-1.77-3.759-4.114l16.646-57.705c.677-2.35-1.37-4.583-3.769-4.113Z"></path></svg>
@@ -0,0 +1,44 @@
+#root {
+    max-width: 1280px;
+    margin: 0 auto;
+    padding: 2rem;
+    text-align: center;
+    --cell-background-color: #293136;
+    --cell-color: #cbe3ef;
+}
+
+tr:nth-child(even) {
+    background: #F2F2F2;
+}
+
+tr:nth-child(odd) {
+    background: #FFF;
+}
+
+th, td {
+    padding-left: 1rem;
+    padding-right: 1rem;
+    background-color: var(--cell-background-color);
+    color: var(--cell-color);
+}
+
+textarea#query-input {
+  height: 5em;
+  width: 50em;
+}
+
+button#query-button {
+  height: 5em;
+  vertical-align: top;
+}
+
+table#query-output {
+  float: none;
+  clear: both;
+}
+
+p#footer {
+  float: none;
+  clear: both;
+  vertical-align: bottom;
+}
@@ -0,0 +1,88 @@
+import { Component } from "react";
+import "./App.css";
+
+export class Home extends Component {
+  static displayName = Home.name;
+  static sparkdHost = "localhost";
+
+  render() {
+    let socket = null;
+    const wsUrl = `ws://localhost:5268/ws`;
+
+    function connectToSparkd() {
+      if (socket == null) {
+        socket = new WebSocket(wsUrl);
+      }
+      if (socket && socket.readyState === WebSocket.OPEN) {
+        return;
+      }
+
+      const output = document.getElementById("query-output");
+      socket.onopen = (event) => {
+        console.log(`Connected to ${wsUrl}`);
+      };
+
+      socket.onmessage = (event) => {
+        console.log(`Received message: ${event.data}`);
+        output.innerHTML = event.data;
+      };
+
+      socket.onerror = (error) => {
+        console.log(`Error on websocket ${wsUrl}: ${error}`);
+      };
+
+      socket.onclose = (event) => {
+        if (event.wasClean) {
+          const msg = `Connection to ${wsUrl} closed cleanly, code=${event.code}, reason=${event.reason}`;
+          console.log(msg);
+        } else {
+          const msg = `Connection to ${wsUrl} abruptly closed`;
+          console.log(msg);
+        }
+      };
+    }
+
+    function executeQuery() {
+      if (socket == null || !socket) {
+        connectToSparkd();
+      }
+      if (socket == null || !socket) {
+        console.log("Failed to connect to websocket server");
+        return;
+      }
+      if (socket.readyState === WebSocket.OPEN) {
+        const queryInput = document.getElementById("query-input");
+        const rpcReq = {
+          jsonrpc: "2.0",
+          method: "subscribe",
+          params: {
+            query: queryInput.value,
+          },
+          id: 1,
+        };
+        socket.send(JSON.stringify(rpcReq));
+      }
+    }
+
+    return (
+      <div>
+        <h1>Data Stream Query Analyzer</h1>
+        <p>Run queries against the BTS Cloud</p>
+        <div>
+          <textarea id="query-input" placeholder="Enter Query"></textarea>
+          <button id="query-button" onClick={executeQuery}>
+            Execute
+          </button>
+        </div>
+        <table id="query-output"></table>
+        <p id="footer">
+          The <code>ClientApp</code> subdirectory is a standard React
+          application based on the <code>create-react-app</code> template. If
+          you open a command prompt in that directory, you can run{" "}
+          <code>npm</code> commands such as <code>npm test</code> or{" "}
+          <code>npm install</code>.
+        </p>
+      </div>
+    );
+  }
+}
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" class="iconify iconify--logos" width="35.93" height="32" preserveAspectRatio="xMidYMid meet" viewBox="0 0 256 228"><path fill="#00D8FF" d="M210.483 73.824a171.49 171.49 0 0 0-8.24-2.597c.465-1.9.893-3.777 1.273-5.621c6.238-30.281 2.16-54.676-11.769-62.708c-13.355-7.7-35.196.329-57.254 19.526a171.23 171.23 0 0 0-6.375 5.848a155.866 155.866 0 0 0-4.241-3.917C100.759 3.829 77.587-4.822 63.673 3.233C50.33 10.957 46.379 33.89 51.995 62.588a170.974 170.974 0 0 0 1.892 8.48c-3.28.932-6.445 1.924-9.474 2.98C17.309 83.498 0 98.307 0 113.668c0 15.865 18.582 31.778 46.812 41.427a145.52 145.52 0 0 0 6.921 2.165a167.467 167.467 0 0 0-2.01 9.138c-5.354 28.2-1.173 50.591 12.134 58.266c13.744 7.926 36.812-.22 59.273-19.855a145.567 145.567 0 0 0 5.342-4.923a168.064 168.064 0 0 0 6.92 6.314c21.758 18.722 43.246 26.282 56.54 18.586c13.731-7.949 18.194-32.003 12.4-61.268a145.016 145.016 0 0 0-1.535-6.842c1.62-.48 3.21-.974 4.76-1.488c29.348-9.723 48.443-25.443 48.443-41.52c0-15.417-17.868-30.326-45.517-39.844Zm-6.365 70.984c-1.4.463-2.836.91-4.3 1.345c-3.24-10.257-7.612-21.163-12.963-32.432c5.106-11 9.31-21.767 12.459-31.957c2.619.758 5.16 1.557 7.61 2.4c23.69 8.156 38.14 20.213 38.14 29.504c0 9.896-15.606 22.743-40.946 31.14Zm-10.514 20.834c2.562 12.94 2.927 24.64 1.23 33.787c-1.524 8.219-4.59 13.698-8.382 15.893c-8.067 4.67-25.32-1.4-43.927-17.412a156.726 156.726 0 0 1-6.437-5.87c7.214-7.889 14.423-17.06 21.459-27.246c12.376-1.098 24.068-2.894 34.671-5.345a134.17 134.17 0 0 1 1.386 6.193ZM87.276 214.515c-7.882 2.783-14.16 2.863-17.955.675c-8.075-4.657-11.432-22.636-6.853-46.752a156.923 156.923 0 0 1 1.869-8.499c10.486 2.32 22.093 3.988 34.498 4.994c7.084 9.967 14.501 19.128 21.976 27.15a134.668 134.668 0 0 1-4.877 4.492c-9.933 8.682-19.886 14.842-28.658 17.94ZM50.35 144.747c-12.483-4.267-22.792-9.812-29.858-15.863c-6.35-5.437-9.555-10.836-9.555-15.216c0-9.322 13.897-21.212 37.076-29.293c2.813-.98 5.757-1.905 8.812-2.773c3.204 10.42 7.406 21.315 12.477 32.332c-5.137 11.18-9.399 22.249-12.634 32.792a134.718 134.718 0 0 1-6.318-1.979Zm12.378-84.26c-4.811-24.587-1.616-43.134 6.425-47.789c8.564-4.958 27.502 2.111 47.463 19.835a144.318 144.318 0 0 1 3.841 3.545c-7.438 7.987-14.787 17.08-21.808 26.988c-12.04 1.116-23.565 2.908-34.161 5.309a160.342 160.342 0 0 1-1.76-7.887Zm110.427 27.268a347.8 347.8 0 0 0-7.785-12.803c8.168 1.033 15.994 2.404 23.343 4.08c-2.206 7.072-4.956 14.465-8.193 22.045a381.151 381.151 0 0 0-7.365-13.322Zm-45.032-43.861c5.044 5.465 10.096 11.566 15.065 18.186a322.04 322.04 0 0 0-30.257-.006c4.974-6.559 10.069-12.652 15.192-18.18ZM82.802 87.83a323.167 323.167 0 0 0-7.227 13.238c-3.184-7.553-5.909-14.98-8.134-22.152c7.304-1.634 15.093-2.97 23.209-3.984a321.524 321.524 0 0 0-7.848 12.897Zm8.081 65.352c-8.385-.936-16.291-2.203-23.593-3.793c2.26-7.3 5.045-14.885 8.298-22.6a321.187 321.187 0 0 0 7.257 13.246c2.594 4.48 5.28 8.868 8.038 13.147Zm37.542 31.03c-5.184-5.592-10.354-11.779-15.403-18.433c4.902.192 9.899.29 14.978.29c5.218 0 10.376-.117 15.453-.343c-4.985 6.774-10.018 12.97-15.028 18.486Zm52.198-57.817c3.422 7.8 6.306 15.345 8.596 22.52c-7.422 1.694-15.436 3.058-23.88 4.071a382.417 382.417 0 0 0 7.859-13.026a347.403 347.403 0 0 0 7.425-13.565Zm-16.898 8.101a358.557 358.557 0 0 1-12.281 19.815a329.4 329.4 0 0 1-23.444.823c-7.967 0-15.716-.248-23.178-.732a310.202 310.202 0 0 1-12.513-19.846h.001a307.41 307.41 0 0 1-10.923-20.627a310.278 310.278 0 0 1 10.89-20.637l-.001.001a307.318 307.318 0 0 1 12.413-19.761c7.613-.576 15.42-.876 23.31-.876H128c7.926 0 15.743.303 23.354.883a329.357 329.357 0 0 1 12.335 19.695a358.489 358.489 0 0 1 11.036 20.54a329.472 329.472 0 0 1-11 20.722Zm22.56-122.124c8.572 4.944 11.906 24.881 6.52 51.026c-.344 1.668-.73 3.367-1.15 5.09c-10.622-2.452-22.155-4.275-34.23-5.408c-7.034-10.017-14.323-19.124-21.64-27.008a160.789 160.789 0 0 1 5.888-5.4c18.9-16.447 36.564-22.941 44.612-18.3ZM128 90.808c12.625 0 22.86 10.235 22.86 22.86s-10.235 22.86-22.86 22.86s-22.86-10.235-22.86-22.86s10.235-22.86 22.86-22.86Z"></path></svg>
@@ -0,0 +1,68 @@
+:root {
+  font-family: Inter, system-ui, Avenir, Helvetica, Arial, sans-serif;
+  line-height: 1.5;
+  font-weight: 400;
+
+  color-scheme: light dark;
+  color: rgba(255, 255, 255, 0.87);
+  background-color: #242424;
+
+  font-synthesis: none;
+  text-rendering: optimizeLegibility;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+}
+
+a {
+  font-weight: 500;
+  color: #646cff;
+  text-decoration: inherit;
+}
+a:hover {
+  color: #535bf2;
+}
+
+body {
+  margin: 0;
+  display: flex;
+  place-items: center;
+  min-width: 320px;
+  min-height: 100vh;
+}
+
+h1 {
+  font-size: 3.2em;
+  line-height: 1.1;
+}
+
+button {
+  border-radius: 8px;
+  border: 1px solid transparent;
+  padding: 0.6em 1.2em;
+  font-size: 1em;
+  font-weight: 500;
+  font-family: inherit;
+  background-color: #1a1a1a;
+  cursor: pointer;
+  transition: border-color 0.25s;
+}
+button:hover {
+  border-color: #646cff;
+}
+button:focus,
+button:focus-visible {
+  outline: 4px auto -webkit-focus-ring-color;
+}
+
+@media (prefers-color-scheme: light) {
+  :root {
+    color: #213547;
+    background-color: #ffffff;
+  }
+  a:hover {
+    color: #747bff;
+  }
+  button {
+    background-color: #f9f9f9;
+  }
+}
@@ -0,0 +1,10 @@
+import React from 'react'
+import ReactDOM from 'react-dom/client'
+import {Home} from './App.jsx'
+import './index.css'
+
+ReactDOM.createRoot(document.getElementById('root')).render(
+  <React.StrictMode>
+    <Home />
+  </React.StrictMode>,
+)
@@ -0,0 +1,60 @@
+import { fileURLToPath, URL } from 'node:url';
+
+import { defineConfig } from 'vite';
+import plugin from '@vitejs/plugin-react';
+import fs from 'fs';
+import path from 'path';
+import child_process from 'child_process';
+
+const baseFolder =
+    process.env.APPDATA !== undefined && process.env.APPDATA !== ''
+        ? `${process.env.APPDATA}/ASP.NET/https`
+        : `${process.env.HOME}/.aspnet/https`;
+
+const certificateArg = process.argv.map(arg => arg.match(/--name=(?<value>.+)/i)).filter(Boolean)[0];
+const certificateName = certificateArg ? certificateArg.groups.value : "bts.datastreamwebapp.client";
+
+if (!certificateName) {
+    console.error('Invalid certificate name. Run this script in the context of an npm/yarn script or pass --name=<<app>> explicitly.')
+    process.exit(-1);
+}
+
+const certFilePath = path.join(baseFolder, `${certificateName}.pem`);
+const keyFilePath = path.join(baseFolder, `${certificateName}.key`);
+
+if (!fs.existsSync(certFilePath) || !fs.existsSync(keyFilePath)) {
+    if (0 !== child_process.spawnSync('dotnet', [
+        'dev-certs',
+        'https',
+        '--export-path',
+        certFilePath,
+        '--format',
+        'Pem',
+        '--no-password',
+    ], { stdio: 'inherit', }).status) {
+        throw new Error("Could not create certificate.");
+    }
+}
+
+// https://vitejs.dev/config/
+export default defineConfig({
+    plugins: [plugin()],
+    resolve: {
+        alias: {
+            '@': fileURLToPath(new URL('./src', import.meta.url))
+        }
+    },
+    server: {
+        proxy: {
+            '^/weatherforecast': {
+                target: 'https://localhost:7128/',
+                secure: false
+            }
+        },
+        port: 5173,
+        https: {
+            key: fs.readFileSync(keyFilePath),
+            cert: fs.readFileSync(certFilePath),
+        }
+    }
+})
@@ -0,0 +1,35 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <InvariantGlobalization>true</InvariantGlobalization>
+    <SpaRoot>..\Bts.DataStreamWebApp.Client</SpaRoot>
+    <SpaProxyLaunchCommand>npm run dev</SpaProxyLaunchCommand>
+    <SpaProxyServerUrl>https://localhost:5173</SpaProxyServerUrl>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="CommandLineParser" Version="2.9.1" />
+    <PackageReference Include="Microsoft.AspNetCore.SpaProxy">
+      <Version>8.*-*</Version>
+    </PackageReference>
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.4.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Bts.DataStreamWebApp.Client\Bts.DataStreamWebApp.Client.esproj">
+      <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
+    </ProjectReference>
+    <ProjectReference Include="..\DataStream\DataStream.csproj" />
+    <ProjectReference Include="..\SharedStreams\SharedStreams.csproj" />
+    <ProjectReference Include="..\..\client\spark_api\spark_api.csproj" />
+    <ProjectReference Include="..\..\client\spark_websocket\spark_websocket.csproj" />
+  </ItemGroup>
+
+  <!-- <ItemGroup>
+    <Content Update="wwwroot\alt-index.html" CopyToPublishDirectory="Never" />
+  </ItemGroup> -->
+</Project>
@@ -0,0 +1,6 @@
+@Bts.DataStreamWebApp.Server_HostAddress = http://localhost:5268
+
+GET {{Bts.DataStreamWebApp.Server_HostAddress}}/weatherforecast/
+Accept: application/json
+
+###
@@ -0,0 +1,107 @@
+namespace Bts.DataStreamWebApp.Server.Controllers;
+
+using BCG;
+
+using bts.api.core;
+using bts.websocket_core.json_rpc;
+
+using Bts.DataStreamExpressions;
+
+using Microsoft.AspNetCore.Mvc;
+
+using Spark.Core.Disposables;
+
+using System.Net.WebSockets;
+using System.Text;
+using System.Text.Json;
+
+[Route("/ws")]
+public class DataStreamSubscriptionController(ILogger<DataStreamSubscriptionController> logger) : ControllerBase {
+   readonly ILogger<DataStreamSubscriptionController> logger = logger;
+   IDisposable? streamSubscription;
+
+   [Route("/ws")]
+   public async Task Get() {
+      if (!HttpContext.WebSockets.IsWebSocketRequest) {
+         logger.LogError("Expected websocket request on path '{}'", HttpContext.Request.Path);
+         return;
+      }
+      Console.WriteLine("Establishing websocket connection...");
+      using var webSocket = await HttpContext.WebSockets.AcceptWebSocketAsync();
+      Console.WriteLine($"Websocket connection established.");
+      await runWebSocketServer(null, "bts", string.Empty, webSocket);
+   }
+
+   public static async Task Echo(WebSocket webSocket) {
+      var buffer = new byte[1024 * 4];
+      var receiveResult = await webSocket.ReceiveAsync(
+          new ArraySegment<byte>(buffer), CancellationToken.None);
+
+      while (!receiveResult.CloseStatus.HasValue) {
+         await webSocket.SendAsync(
+             new ArraySegment<byte>(buffer, 0, receiveResult.Count),
+             receiveResult.MessageType,
+             receiveResult.EndOfMessage,
+             CancellationToken.None);
+
+         receiveResult = await webSocket.ReceiveAsync(
+             new ArraySegment<byte>(buffer), CancellationToken.None);
+      }
+
+      await webSocket.CloseAsync(
+          receiveResult.CloseStatus.Value,
+          receiveResult.CloseStatusDescription,
+          CancellationToken.None);
+   }
+
+   async Task<int> runWebSocketServer(string? sparkd, string user, string password, WebSocket webSocket) {
+      var context = ServiceContext.create(sparkd);
+      await context.login(user, password);
+      var buffer = new byte[1024 * 4];
+      var receiveResult = await webSocket.ReceiveAsync(
+          new ArraySegment<byte>(buffer), CancellationToken.None);
+
+      try {
+         while (!receiveResult.CloseStatus.HasValue) {
+            receiveResult = await webSocket.ReceiveAsync(
+                new ArraySegment<byte>(buffer), CancellationToken.None);
+            var msg = Encoding.UTF8.GetString(buffer, 0, receiveResult.Count);
+            var rpcReq = JsonSerializer.Deserialize<JsonRpcRequest<DataStreamSubscription>>(msg);
+            var query = rpcReq?.Params?.Query ?? throw new InvalidOperationException(
+               "Failed to parse JsonRpcRequest.Params");
+            var exp = DataStreamExpressionsInterpreter.Evaluate(query);
+            if (exp is null) {
+               Console.WriteLine($"Invalid query expression: {query}.");
+               continue;
+            }
+            var vs = exp.getView(new Dictionary<string, StatementExpression>(0));
+            Disposable.dispose(ref streamSubscription);
+            vs.onChange += OnStreamChanged;
+            streamSubscription = Disposable.Create(() => vs.onChange -= OnStreamChanged);
+         }
+      } catch (Exception ex) {
+         Console.WriteLine($"Exception on WebsocketServer thread: {ex}");
+         return 1;
+      }
+
+      return 0;
+
+      async void OnStreamChanged(object newValue) {
+         if (newValue is not DataPacket dp) {
+            Console.WriteLine(
+               $"OnStreamChanged delegate expected DataPacket (actually received {newValue?.GetType()}.");
+            return;
+         }
+         Console.WriteLine("Received stream update.");
+         var added_rows_str = dp.addedRows.get_printed_rows(val => val.Length);
+         var msg = $"Received new rows:\n{added_rows_str}";
+         var encoded = Encoding.UTF8.GetBytes(msg);
+         var payload = new ArraySegment<byte>(encoded, 0, encoded.Length);
+         await webSocket.SendAsync(
+             payload,
+             receiveResult.MessageType,
+             receiveResult.EndOfMessage,
+             CancellationToken.None);
+      }
+   }
+}
@@ -0,0 +1,22 @@
+namespace Bts.DataStreamWebApp.Server.Controllers;
+using Microsoft.AspNetCore.Mvc;
+
+[ApiController]
+[Route("[controller]")]
+public class WeatherForecastController(ILogger<WeatherForecastController> logger) : ControllerBase {
+   static readonly string[] Summaries = [
+      "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
+   ];
+
+   readonly ILogger<WeatherForecastController> _logger = logger;
+
+   [HttpGet(Name = "GetWeatherForecast")]
+   public IEnumerable<WeatherForecast> Get() {
+      return Enumerable.Range(1, 5).Select(index => new WeatherForecast {
+         Date = DateOnly.FromDateTime(DateTime.Now.AddDays(index)),
+         TemperatureC = Random.Shared.Next(-20, 55),
+         Summary = Summaries[Random.Shared.Next(Summaries.Length)]
+      })
+      .ToArray();
+   }
+}
@@ -0,0 +1,8 @@
+namespace Bts.DataStreamWebApp.Server;
+
+using System.Text.Json.Serialization;
+
+public class DataStreamSubscription {
+   [JsonPropertyName("query")]
+   public string? Query { get; set; }
+}
@@ -0,0 +1,8 @@
+namespace Bts.DataStreamWebApp.Server;
+
+using BCG;
+
+class DataStreamUpdate {
+   public List<IBlueRow> addedRows { get; set; } = new(0);
+   public List<IBlueRow> deletedRows { get; set; } = new(0);
+}
@@ -0,0 +1,14 @@
+namespace Bts.DataStreamWebApp.Server;
+
+using CommandLine;
+
+class DataStreamWebAppServerOptions {
+   [Option("sparkd")]
+   public string? sparkd { get; set; }
+
+   [Option("user", Default = "bts")]
+   public string? user { get; set; }
+
+   [Option("password", Default = "")]
+   public string? password { get; set; }
+}
@@ -0,0 +1,58 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
+
+using System;
+using System.Net.WebSockets;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Bts.DataStreamWebApp.Server {
+   // public class DataStreamWebSocketHandler {
+   //    readonly WebSocketConnectionManager _connectionManager = new();
+   //    readonly ILogger<DataStreamWebSocketHandler> _logger;
+
+   //    public DataStreamWebSocketHandler(
+   //       WebSocketConnectionManager connectionManager,
+   //       ILogger<DataStreamWebSocketHandler> logger
+   //    ) {
+   //       _connectionManager = connectionManager;
+   //       _logger = logger;
+   //    }
+
+   //    public async Task HandleWebSocket(HttpContext context, WebSocket webSocket) {
+   //       var socketId = _connectionManager.AddSocket(webSocket);
+
+   //       _logger.LogInformation($"WebSocket connection established with ID {socketId}");
+
+   //       while (webSocket.State == WebSocketState.Open) {
+   //          var message = await ReceiveMessageAsync(webSocket);
+   //          if (message != null) {
+   //             _logger.LogInformation($"Received message from ID {socketId}: {message}");
+   //             await BroadcastMessageAsync(message);
+   //          }
+   //       }
+
+   //       _connectionManager.RemoveSocket(socketId);
+   //       _logger.LogInformation($"WebSocket connection closed with ID {socketId}");
+   //    }
+
+   //    async Task<string?> ReceiveMessageAsync(WebSocket webSocket) {
+   //       var buffer = new byte[1024];
+   //       var result = await webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
+
+   //       if (result.CloseStatus.HasValue) {
+   //          return null;
+   //       }
+
+   //       return System.Text.Encoding.UTF8.GetString(buffer, 0, result.Count);
+   //    }
+
+   //    async Task BroadcastMessageAsync(string message) {
+   //       foreach (var socket in _connectionManager.GetAllSockets()) {
+   //          if (socket.Value.State == WebSocketState.Open) {
+   //             await socket.Value.SendAsync(System.Text.Encoding.UTF8.GetBytes(message), WebSocketMessageType.Text, true, CancellationToken.None);
+   //          }
+   //       }
+   //    }
+   // }
+}
@@ -0,0 +1,159 @@
+using BCG;
+
+using bts;
+using bts.api.core;
+using bts.utils;
+using bts.websocket_core.json_rpc;
+
+using Bts.DataStreamExpressions;
+using Bts.DataStreamWebApp.Server;
+using Bts.DataStreamWebApp.Server.Controllers;
+
+using CommandLine;
+
+using mbts.config;
+
+using System.Net.WebSockets;
+using System.Reactive.Disposables;
+using System.Reactive.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+static string fmtReq(HttpRequest req) =>
+   $"{req.Protocol}://{req.Host}/{req.Path}?{req.QueryString}";
+
+static string fmtDataPacket(DataPacket dp) {
+   var sb = new StringBuilder();
+   var rows = dp.addedRows.Cast<IBlueRow>().ToList();
+   var colWidths = dp.schema.columnInfo.Select(c => rows.Max(r => r[c.colNo]?.ToString()?.Length ?? 0)).ToArray();
+   foreach (IBlueRow r in dp.addedRows) {
+      for (int i = 0; i < colWidths.Length; i++) {
+         var str = r[i]?.ToString() ?? string.Empty;
+         if (i > 0) {
+            sb.Append(" | ");
+         }
+         sb.Append(str);
+         var width = colWidths[i];
+         if (str.Length < width) {
+            sb.Append(new string(' ', width - str.Length));
+         }
+      }
+      sb.AppendLine();
+   }
+   return sb.ToString();
+}
+
+var parser = new Parser(ps => {
+   ps.CaseInsensitiveEnumValues = true;
+   ps.HelpWriter = Console.Out;
+});
+
+await parser.ParseArguments<DataStreamWebAppServerOptions>(args).
+   MapResult(run, errors => Task.FromResult(1));
+
+async Task<int> run(DataStreamWebAppServerOptions opts) {
+   BTSNativeMethods.provide_command_line(args, args.Length);
+   Configuration.initialize();
+   var context = ServiceContext.create(opts.sparkd);
+   await context.login(opts.user!, opts.password!);
+   var vsWorkLoop = Observable.Interval(TimeSpan.FromMilliseconds(200)).Subscribe(_ => {
+      ViewStreamDatabase.instance.doWork();
+      MasterWorker.getInstance(false).doWork();
+   });
+   var builder = WebApplication.CreateBuilder(args);
+   builder.Services.AddDirectoryBrowser();
+   var app = builder.Build();
+   var wsOpts = new WebSocketOptions {
+      KeepAliveInterval = TimeSpan.FromMinutes(2)
+   };
+   app.UseWebSockets(wsOpts);
+   app.UseDefaultFiles();
+   app.UseStaticFiles();
+   app.MapFallbackToFile("/index.html");
+
+   app.Use(async (context, next) => {
+      var reqDesc = fmtReq(context.Request);
+      Console.WriteLine($"Webserver received: {reqDesc}");
+      if (context.Request.Path == "/ws") {
+         if (context.WebSockets.IsWebSocketRequest) {
+            Console.WriteLine("Accepting websocket connection...");
+            using var webSocket = await context.WebSockets.AcceptWebSocketAsync();
+            Console.WriteLine("Websocket connection accepted.");
+            await runWebSocketServer(
+               opts.sparkd, opts.user!, opts.password!, webSocket);
+         } else {
+            context.Response.StatusCode = StatusCodes.Status400BadRequest;
+         }
+      } else {
+         Console.WriteLine($"Webserver ignoring req: {reqDesc}");
+         await next(context);
+      }
+   });
+
+   try {
+      await app.RunAsync();
+   } catch (Exception ex) {
+      Console.WriteLine($"Exception on DataStreamWebsocketServer thread: {ex}");
+      return 1;
+   }
+   Spark.Core.Disposables.Disposable.dispose(ref vsWorkLoop);
+   return 0;
+}
+
+async Task<int> runWebSocketServer(string? sparkd, string user, string password, WebSocket webSocket) {
+   var buffer = new byte[1024 * 4];
+   var receiveResult = await webSocket.ReceiveAsync(
+       new ArraySegment<byte>(buffer), CancellationToken.None);
+
+   try {
+      while (!receiveResult.CloseStatus.HasValue) {
+         Console.WriteLine("Awaiting websocket message from client");
+         receiveResult = await webSocket.ReceiveAsync(
+             new ArraySegment<byte>(buffer), CancellationToken.None);
+         var msg = Encoding.UTF8.GetString(buffer, 0, receiveResult.Count);
+         var rpcReq = JsonSerializer.Deserialize<JsonRpcRequest<DataStreamSubscription>>(msg);
+         var queryArgs = rpcReq!.Params!;
+         // var queryArgs = new DataStreamSubscription { Query = msg };
+         var exp = DataStreamExpressionsInterpreter.Evaluate(queryArgs.Query!);
+         if (exp is null) {
+            Console.WriteLine($"Invalid query expression: {queryArgs.Query}.");
+            continue;
+         }
+         var vs = exp.getView(new Dictionary<string, StatementExpression>(0));
+         Console.WriteLine("Subscribing to stream...");
+         vs.onChange += onStreamChanged;
+
+         await webSocket.SendAsync(
+             new ArraySegment<byte>(buffer, 0, receiveResult.Count),
+             receiveResult.MessageType,
+             receiveResult.EndOfMessage,
+             CancellationToken.None);
+      }
+   } catch (Exception ex) {
+      Console.WriteLine($"Exception on WebsocketServer thread: {ex}");
+      return 1;
+   }
+
+   return 0;
+
+   async void onStreamChanged(object newValue) {
+      if (newValue is not DataPacket dp) {
+         Console.WriteLine(
+            $"OnStreamChanged delegate expected DataPacket (actually received {newValue?.GetType()}.");
+         return;
+      }
+      Console.WriteLine("Received stream update.");
+      var sb = new StringBuilder();
+      var updateDesc = fmtDataPacket(dp);
+      var msg = $"Received new rows:\n{updateDesc}";
+      // var payload = new ReadOnlyMemory<byte>([.. msg]);
+      var encoded = Encoding.UTF8.GetBytes(msg);
+      var payload = new ArraySegment<byte>(encoded, 0, encoded.Length);
+      await webSocket.SendAsync(
+          payload,
+          receiveResult.MessageType,
+          receiveResult.EndOfMessage,
+          CancellationToken.None);
+   }
+}
@@ -0,0 +1,48 @@
+{
+  "profiles": {
+    "default": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "applicationUrl": "http://localhost:5400"
+    },
+    "http": {
+      "commandName": "Project",
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "ASPNETCORE_HOSTINGSTARTUPASSEMBLIES": "Microsoft.AspNetCore.SpaProxy"
+      },
+      "dotnetRunMessages": true,
+      "applicationUrl": "http://localhost:5268"
+    },
+    "https": {
+      "commandName": "Project",
+      "launchUrl": "swagger",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "ASPNETCORE_HOSTINGSTARTUPASSEMBLIES": "Microsoft.AspNetCore.SpaProxy"
+      },
+      "dotnetRunMessages": true,
+      "applicationUrl": "https://localhost:7128;http://localhost:5268"
+    },
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "ASPNETCORE_HOSTINGSTARTUPASSEMBLIES": "Microsoft.AspNetCore.SpaProxy"
+      }
+    }
+  },
+  "$schema": "http://json.schemastore.org/launchsettings.json",
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:2083",
+      "sslPort": 44383
+    }
+  }
+}
@@ -0,0 +1,12 @@
+namespace Bts.DataStreamWebApp.Server;
+
+public class WeatherForecast
+{
+   public DateOnly Date { get; set; }
+
+   public int TemperatureC { get; set; }
+
+   public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
+
+   public string? Summary { get; set; }
+}
@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Concurrent;
+using System.Net.WebSockets;
+
+namespace Bts.DataStreamWebApp.Server {
+   // public class WebSocketConnectionManager {
+   //    private readonly ConcurrentDictionary<Guid, WebSocket> _sockets = new ConcurrentDictionary<Guid, WebSocket>();
+
+   //    public Guid AddSocket(WebSocket socket) {
+   //       var socketId = Guid.NewGuid();
+   //       _sockets.TryAdd(socketId, socket);
+   //       return socketId;
+   //    }
+
+   //    public WebSocket? GetSocket(Guid socketId) {
+   //       _sockets.TryGetValue(socketId, out var socket);
+   //       return socket;
+   //    }
+
+   //    public ConcurrentDictionary<Guid, WebSocket>.ValueCollection GetAllSockets() {
+   //       return _sockets.Values;
+   //    }
+
+   //    public Guid? GetSocketId(WebSocket socket) {
+   //       foreach (var (key, value) in _sockets) {
+   //          if (value == socket) {
+   //             return key;
+   //          }
+   //       }
+   //       return null;
+   //    }
+
+   //    public void RemoveSocket(Guid socketId) {
+   //       _sockets.TryRemove(socketId, out _);
+   //    }
+   // }
+}
@@ -0,0 +1,8 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  }
+}
@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*"
+}
@@ -0,0 +1,168 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8" />
+    <title></title>
+    <style>
+        table {
+            border: 0
+        }
+
+        .commslog-data {
+            font-family: Consolas, Courier New, Courier, monospace;
+        }
+
+        .commslog-server {
+            background-color: red;
+            color: white
+        }
+
+        .commslog-client {
+            background-color: green;
+            color: white
+        }
+    </style>
+</head>
+<body>
+    <h1>ALT WebSocket Sample Application</h1>
+    <p id="stateLabel">Ready to connect...</p>
+    <div>
+        <label for="connectionUrl">WebSocket Server URL:</label>
+        <input id="connectionUrl" />
+        <button id="connectButton" type="submit">Connect</button>
+    </div>
+    <p></p>
+    <div>
+        <label for="sendMessage">Message to send:</label>
+        <input id="sendMessage" disabled />
+        <button id="sendButton" type="submit" disabled>Send</button>
+        <button id="closeButton" disabled>Close Socket</button>
+    </div>
+
+    <h2>Communication Log</h2>
+    <table style="width: 800px">
+        <thead>
+            <tr>
+                <td style="width: 100px">From</td>
+                <td style="width: 100px">To</td>
+                <td>Data</td>
+            </tr>
+        </thead>
+        <tbody id="commsLog">
+        </tbody>
+    </table>
+
+    <script>
+        var connectionUrl = document.getElementById("connectionUrl");
+        var connectButton = document.getElementById("connectButton");
+        var stateLabel = document.getElementById("stateLabel");
+        var sendMessage = document.getElementById("sendMessage");
+        var sendButton = document.getElementById("sendButton");
+        var commsLog = document.getElementById("commsLog");
+        var closeButton = document.getElementById("closeButton");
+        var socket;
+
+        var scheme = document.location.protocol === "https:" ? "wss" : "ws";
+        var port = document.location.port ? (":" + document.location.port) : "";
+
+        connectionUrl.value = scheme + "://" + document.location.hostname + port + "/ws" ;
+
+        function updateState() {
+            function disable() {
+                sendMessage.disabled = true;
+                sendButton.disabled = true;
+                closeButton.disabled = true;
+            }
+            function enable() {
+                sendMessage.disabled = false;
+                sendButton.disabled = false;
+                closeButton.disabled = false;
+            }
+
+            connectionUrl.disabled = true;
+            connectButton.disabled = true;
+
+            if (!socket) {
+                disable();
+            } else {
+                switch (socket.readyState) {
+                    case WebSocket.CLOSED:
+                        stateLabel.innerHTML = "Closed";
+                        disable();
+                        connectionUrl.disabled = false;
+                        connectButton.disabled = false;
+                        break;
+                    case WebSocket.CLOSING:
+                        stateLabel.innerHTML = "Closing...";
+                        disable();
+                        break;
+                    case WebSocket.CONNECTING:
+                        stateLabel.innerHTML = "Connecting...";
+                        disable();
+                        break;
+                    case WebSocket.OPEN:
+                        stateLabel.innerHTML = "Open";
+                        enable();
+                        break;
+                    default:
+                        stateLabel.innerHTML = "Unknown WebSocket State: " + htmlEscape(socket.readyState);
+                        disable();
+                        break;
+                }
+            }
+        }
+
+        closeButton.onclick = function () {
+            if (!socket || socket.readyState !== WebSocket.OPEN) {
+                alert("socket not connected");
+            }
+            socket.close(1000, "Closing from client");
+        };
+
+        sendButton.onclick = function () {
+            if (!socket || socket.readyState !== WebSocket.OPEN) {
+                alert("socket not connected");
+            }
+            var data = sendMessage.value;
+            socket.send(data);
+            commsLog.innerHTML += '<tr>' +
+                '<td class="commslog-client">Client</td>' +
+                '<td class="commslog-server">Server</td>' +
+                '<td class="commslog-data">' + htmlEscape(data) + '</td></tr>';
+        };
+
+        connectButton.onclick = function() {
+            stateLabel.innerHTML = "Connecting";
+            socket = new WebSocket(connectionUrl.value);
+            socket.onopen = function (event) {
+                updateState();
+                commsLog.innerHTML += '<tr>' +
+                    '<td colspan="3" class="commslog-data">Connection opened</td>' +
+                '</tr>';
+            };
+            socket.onclose = function (event) {
+                updateState();
+                commsLog.innerHTML += '<tr>' +
+                    '<td colspan="3" class="commslog-data">Connection closed. Code: ' + htmlEscape(event.code) + '. Reason: ' + htmlEscape(event.reason) + '</td>' +
+                '</tr>';
+            };
+            socket.onerror = updateState;
+            socket.onmessage = function (event) {
+                commsLog.innerHTML += '<tr>' +
+                    '<td class="commslog-server">Server</td>' +
+                    '<td class="commslog-client">Client</td>' +
+                    '<td class="commslog-data">' + htmlEscape(event.data) + '</td></tr>';
+            };
+        };
+
+        function htmlEscape(str) {
+            return str.toString()
+                .replace(/&/g, '&amp;')
+                .replace(/"/g, '&quot;')
+                .replace(/'/g, '&#39;')
+                .replace(/</g, '&lt;')
+                .replace(/>/g, '&gt;');
+        }
+    </script>
+</body>
+</html>
@@ -0,0 +1,176 @@
+<!DOCTYPE html>
+<html>
+<head>
+    <meta charset="utf-8" />
+    <title></title>
+    <style>
+        table {
+            border: 0
+        }
+
+        .commslog-data {
+            font-family: Consolas, Courier New, Courier, monospace;
+        }
+
+        .commslog-server {
+            background-color: red;
+            color: white
+        }
+
+        .commslog-client {
+            background-color: green;
+            color: white
+        }
+    </style>
+</head>
+<body>
+    <h1>DataStreams via WebSocket</h1>
+    <p id="stateLabel">Ready to connect...</p>
+    <div>
+        <label for="connectionUrl">WebSocket Server URL:</label>
+        <input id="connectionUrl" />
+        <button id="connectButton" type="submit">Connect</button>
+    </div>
+    <p></p>
+    <div>
+        <label for="sendMessage">Query:</label>
+        <input id="sendMessage" disabled />
+        <button id="sendButton" type="submit" disabled>Send</button>
+        <button id="closeButton" disabled>Close Socket</button>
+    </div>
+
+    <h2>Communication Log</h2>
+    <table style="width: 800px">
+        <thead>
+            <tr>
+                <td style="width: 100px">From</td>
+                <td style="width: 100px">To</td>
+                <td>Data</td>
+            </tr>
+        </thead>
+        <tbody id="commsLog">
+        </tbody>
+    </table>
+
+    <script>
+        var connectionUrl = document.getElementById("connectionUrl");
+        var connectButton = document.getElementById("connectButton");
+        var stateLabel = document.getElementById("stateLabel");
+        var sendMessage = document.getElementById("sendMessage");
+        var sendButton = document.getElementById("sendButton");
+        var commsLog = document.getElementById("commsLog");
+        var closeButton = document.getElementById("closeButton");
+        var socket;
+
+        var scheme = document.location.protocol === "https:" ? "wss" : "ws";
+        var port = document.location.port ? (":" + document.location.port) : "";
+
+        connectionUrl.value = scheme + "://" + document.location.hostname + port + "/ws" ;
+
+        function updateState() {
+            function disable() {
+                sendMessage.disabled = true;
+                sendButton.disabled = true;
+                closeButton.disabled = true;
+            }
+            function enable() {
+                sendMessage.disabled = false;
+                sendButton.disabled = false;
+                closeButton.disabled = false;
+            }
+
+            connectionUrl.disabled = true;
+            connectButton.disabled = true;
+
+            if (!socket) {
+                disable();
+            } else {
+                switch (socket.readyState) {
+                    case WebSocket.CLOSED:
+                        stateLabel.innerHTML = "Closed";
+                        disable();
+                        connectionUrl.disabled = false;
+                        connectButton.disabled = false;
+                        break;
+                    case WebSocket.CLOSING:
+                        stateLabel.innerHTML = "Closing...";
+                        disable();
+                        break;
+                    case WebSocket.CONNECTING:
+                        stateLabel.innerHTML = "Connecting...";
+                        disable();
+                        break;
+                    case WebSocket.OPEN:
+                        stateLabel.innerHTML = "Open";
+                        enable();
+                        break;
+                    default:
+                        stateLabel.innerHTML = "Unknown WebSocket State: " + htmlEscape(socket.readyState);
+                        disable();
+                        break;
+                }
+            }
+        }
+
+        closeButton.onclick = function () {
+            if (!socket || socket.readyState !== WebSocket.OPEN) {
+                alert("socket not connected");
+            }
+            socket.close(1000, "Closing from client");
+        };
+
+        sendButton.onclick = function () {
+            if (!socket || socket.readyState !== WebSocket.OPEN) {
+                alert("socket not connected");
+            }
+            const rpcReq = {
+              jsonrpc: "2.0",
+              method: "subscribe",
+              params: {
+                query: sendMessage.value,
+              },
+              id: 1,
+            };
+            const rpcReqStr = JSON.stringify(rpcReq);
+            socket.send(rpcReqStr);
+            commsLog.innerHTML += '<tr>' +
+                '<td class="commslog-client">Client</td>' +
+                '<td class="commslog-server">Server</td>' +
+                '<td class="commslog-data">' + htmlEscape(rpcReqStr) + '</td></tr>';
+        };
+
+        connectButton.onclick = function() {
+            stateLabel.innerHTML = "Connecting";
+            socket = new WebSocket(connectionUrl.value);
+            socket.onopen = function (event) {
+                updateState();
+                commsLog.innerHTML += '<tr>' +
+                    '<td colspan="3" class="commslog-data">Connection opened</td>' +
+                '</tr>';
+            };
+            socket.onclose = function (event) {
+                updateState();
+                commsLog.innerHTML += '<tr>' +
+                    '<td colspan="3" class="commslog-data">Connection closed. Code: ' + htmlEscape(event.code) + '. Reason: ' + htmlEscape(event.reason) + '</td>' +
+                '</tr>';
+            };
+            socket.onerror = updateState;
+            socket.onmessage = function (event) {
+                commsLog.innerHTML += '<tr>' +
+                    '<td class="commslog-server">Server</td>' +
+                    '<td class="commslog-client">Client</td>' +
+                    '<td class="commslog-data">' + htmlEscape(event.data) + '</td></tr>';
+            };
+        };
+
+        function htmlEscape(str) {
+            return str.toString()
+                .replace(/&/g, '&amp;')
+                .replace(/"/g, '&quot;')
+                .replace(/'/g, '&#39;')
+                .replace(/</g, '&lt;')
+                .replace(/>/g, '&gt;');
+        }
+    </script>
+</body>
+</html>
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <Nullable>enable</Nullable>
  </PropertyGroup>

@@ -0,0 +1,26 @@
+namespace Bts.DataStream;
+
+using BCG;
+
+using Spark.Core.Disposables;
+
+using System;
+using System.Reactive.Linq;
+
+public static class DataStreamExtensions {
+   public static ViewStream AsViewStream(this IObservable<DataPacket> source) =>
+      source as ViewStream ?? new ObservableViewStream(source);
+
+   public static IObservable<DataPacket> AsObservable(this ViewStream source) {
+      return source as IObservable<DataPacket> ?? Observable.Create<DataPacket>(Subscribe);
+
+      IDisposable Subscribe(IObserver<DataPacket> observer) {
+         source.onChange += OnChange;
+         return Disposable.Create(() => source.onChange -= OnChange);
+
+         void OnChange(object? newValue) =>
+            observer.OnNext(newValue as DataPacket ?? throw new ArgumentException(
+               $"Expected DataPacket, got {newValue?.GetType()}", nameof(newValue)));
+      }
+   }
+}
@@ -0,0 +1,62 @@
+// using System;
+// using System.Diagnostics;
+
+// using BCG;
+// using BCG.Utilities.General;
+
+
+// namespace bts {
+
+//     public class PandasStream : ViewStream, IWorker {
+//         //C:\Users\Owner\AppData\Local\Microsoft\WindowsApps\python.exe
+
+//         public PandasStream(ViewStream vs, ViewStreamDatabase vsd, string pandas_code) {
+
+//         }
+
+//         public PandasStream(ViewStream vs, string pandas_code) :
+//         this(vs, ViewStreamDatabase.instance, pandas_code) {
+//         }
+
+
+//         protected override void myOnFirstSubscriber() {
+
+//             // string python_code = @"
+//             //    import winsound
+//             //    frequency = 2500  # Set frequency (in Hz)
+//             //    duration = 1000   # Set duration (in milliseconds)
+//             //    winsound.Beep(frequency, duration)
+//             // ";
+//             string python_code = @"
+//             file_path = \"C:\\Temp\\test2.txt\\"  # r prefix for raw string to avoid escape characters
+//             with open(file_path, \"w\") as f:
+//                 f.write(\"Hello, world!\n\")
+//             ";
+
+//             execute_python_code(python_code);
+//         }
+
+//         static void execute_python_code(string python_code) {
+//             ProcessStartInfo start = new ProcessStartInfo();
+//             start.FileName = "python"; // Python executable
+//             start.Arguments = "-c \"" + python_code.Replace("\"", "\\\"") + "\""; // Pass code as argument
+//             start.UseShellExecute = false;
+//             start.RedirectStandardOutput = true;
+
+//             using (Process process = Process.Start(start)) {
+//                 using (System.IO.StreamReader reader = process.StandardOutput) {
+//                     string result = reader.ReadToEnd();
+//                     Console.Write(result);
+//                 }
+//             }
+//         }
+
+//         protected override void myOnLastSubscriber() {
+//         }
+
+//         public void doWork() {
+
+//         }
+
+//     }
+// }
@@ -0,0 +1,3 @@
+file_path = r"C:\Temp\test2.txt"  # r prefix for raw string to avoid escape characters
+with open(file_path, "w") as f:
+    f.write("Hello, world!\n")
@@ -0,0 +1,34 @@
+namespace Bts.DataStream;
+
+using BCG;
+
+using bts;
+
+using System;
+
+public class ObservableViewStream : ViewStream, IObservable<DataPacket>, IDisposable {
+   readonly IObservable<DataPacket> source;
+   IDisposable? subscription;
+
+   public ObservableViewStream(IObservable<DataPacket> source) =>
+      this.source = source;
+
+   public void Dispose() {
+      subscription?.Dispose();
+      subscription = null;
+   }
+
+   protected override void myOnFirstSubscriber() {
+      Log.isnull(subscription);
+      subscription = source.Subscribe(myFireEvent);
+   }
+
+   protected override void myOnLastSubscriber() {
+      Log.notnull(subscription);
+      subscription.Dispose();
+      subscription = null;
+   }
+
+   IDisposable IObservable<DataPacket>.Subscribe(IObserver<DataPacket> observer) =>
+      source.Subscribe(observer);
+}
@@ -0,0 +1,12 @@
+namespace bts {
+    using BCG;
+
+    using System;
+    using System.Collections;
+
+    public class AddConstantColumnRow {
+        AddConstantColumnRow(IBlueRow r, Tuple<string, Type, object>[] constant_cols) {
+
+        }
+    }
+}
@@ -30,8 +30,8 @@ namespace BCG
           {
              using (FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read))
              {
-                  BinaryFormatter bf = new BinaryFormatter();
 #pragma warning disable SYSLIB0011
+                  BinaryFormatter bf = new BinaryFormatter();
                  BlueTable bt = (BlueTable)bf.Deserialize(fs);
 #pragma warning restore SYSLIB0011
                  mySetRealSource(new BlueRowCollectionStaticStream(bt));
@@ -15,6 +15,11 @@ namespace BCG {
   // data:
   // epochtime, size, serialized data
   [DataStreamUserRespresentation("pers")]
+   // Saves each udpate of a stream into a file. The token is the the unique logical name of the stream,
+   // which maps the name of the directory where the streams are saved. The directory (3rd arg) is the 
+   // parent directory where the token folder is stored. Each file goes up to rolloevr_size after which a new
+   // file is created. The file names are token_epoch_datetime
+   // the first entry in a file is the complete state
   public class PersistorStream : ViewStream {
      private ViewStream _source_stream;
      private string _token;
@@ -11,13 +11,27 @@ using System.Reflection.Metadata;

 namespace BCG {
   public class SnapshotStream : ViewStream {
-
+      public enum SpecificSnapshot {
+         FirstOfDay,
+         LastOfDay
+      };
      private BlueTable _current_table;
      private IClientDeserializer _deserilializer = new ClientUniversalDeserializer();
      public DateTime _snapshot_time;
      public string _snapshot_file;
      public IEnumerable<PlaybackPacket> _packets;
-
+      public SnapshotStream(string snapshot_date, string specific_snapshot, string directory_name, string token) {
+         DateTime dt;
+         var parsed = DateTime.TryParse(snapshot_date, out dt);
+         dt = dt.Date;
+         bts.Log.assert(parsed);
+         SpecificSnapshot specific_snapshot_enum;
+         parsed = Enum.TryParse<SpecificSnapshot>(specific_snapshot, out specific_snapshot_enum);
+         bts.Log.assert(parsed);
+         string snapshot_dt = StreamPersistorUtils.find_snapshot_file($"{directory_name}\\{token}", dt, specific_snapshot_enum);
+         ViewStream rs = new SnapshotStream(snapshot_dt, directory_name, token);
+         mySetRealSource(rs);
+      }

      public SnapshotStream(string snapshot_dt, string directory_name, string token) {
         _snapshot_time = PersistorStream.parse_datetime(snapshot_dt);
@@ -37,6 +37,20 @@ namespace BCG {
      public IEnumerable<PlaybackPacket> packets = new List<PlaybackPacket>();
   }
   public static class StreamPersistorUtils {
+      public static string find_snapshot_file(string directory_name, DateTime snapshot_date, SnapshotStream.SpecificSnapshot specific_snapshot) {
+         DateTime max_dt = DateTime.MinValue;
+         string rv = String.Empty;
+         string[] file_names = Directory.GetFiles(directory_name);
+         for (int i = 0; i < file_names.Count() - 1; i++) {
+            string fn = file_names[i];
+            var dt = parse_datetime_from_filename(fn);
+            if (dt > max_dt) {
+               max_dt = dt;
+               rv = fn;
+            }
+         }
+         return rv;
+      }
      public static string find_snapshot_file(string directory_name, DateTime snapshot_time) {
         string[] file_names = Directory.GetFiles(directory_name);
         for (int i = 0; i < file_names.Count() - 1; i++) {
@@ -1,47 +1,42 @@
-// using System;
-// using System.Collections;
-// using BCG.Utilities;
+using System;
+using System.Collections;

-// namespace BCG
-// {
-// 	/// <summary>
-// 	/// Computes the max for a given column
-// 	/// </summary>
-// 	public class MaxGroupByEvaluator : GroupByEvaluator
-// 	{
+using BCG.Utilities;

-//       public MaxGroupByEvaluator (string outputCol, string[] groupByCols) : base (outputCol, groupByCols)
-//       {}
+namespace BCG {
+    /// <summary>
+    /// Computes the max for a given column
+    /// </summary>
+    public class MaxGroupByEvaluator : GroupByEvaluator {

-//       public MaxGroupByEvaluator (string colMapEpression, string outputCol, string[] groupByCols)
-//          : base (colMapEpression, outputCol, groupByCols)   {}
+        public MaxGroupByEvaluator(string outputCol, string[] groupByCols) : base(outputCol, groupByCols) { }

-//       public override IBlueRow evaluate (DataPacket dp)  
-//       {
-//          myOutputTable = myOutputTable == null ? new GroupByOutputTable (dp.schema) :
-//             myOutputTable;
-//          string hashString = BlueDataUtility.rowToString (GroupByStream.getRepRow (dp), myGroupByCols);
-//          IBlueRow currMaxRow = myOutputTable.getRow (hashString);
-//          IBlueRow maxRow = BlueDataUtility.computeMaxRow (dp.deletedRows, myOutputColumn);
-//          if (maxRow != null)
-//          {
-//             BlueEventLog.logAssert (currMaxRow != null);
-//             BlueEventLog.logAssert (BlueDataUtility.compareRows (maxRow, currMaxRow, myOutputColumn) <= 0);
-//             if (BlueDataUtility.compareRows (maxRow, currMaxRow, myOutputColumn) == 0)
-//             {
-//                maxRow = BlueDataUtility.computeMaxRow (dp.newRows, myOutputColumn);
-//                if (maxRow == null)
-//                   myOutputTable.removeRow (hashString);
-//                else
-//                   myOutputTable.addRow (maxRow, hashString);
-//             }
-//          }
-//          maxRow = BlueDataUtility.computeMaxRow (dp.addedRows, myOutputColumn);
-//          // if the row was replaced in the above lines, then currMaxRow < maxRow, so the if below would never return a true,
-//          // otherwise if maxRow > currMaxRow then its replaced
-//          if (maxRow != null && (currMaxRow == null || BlueDataUtility.compareRows (maxRow, currMaxRow, myOutputColumn) > 0))
-//             myOutputTable.addRow (maxRow, hashString);
-//          return myProject (myOutputTable.getRow (hashString));
-//       }
-// 	}
-// }
+        public MaxGroupByEvaluator(string colMapEpression, string outputCol, string[] groupByCols)
+           : base(colMapEpression, outputCol, groupByCols) { }
+
+        public override IBlueRow evaluate(DataPacket dp) {
+            myOutputTable = myOutputTable == null ? new GroupByOutputTable(dp.schema) :
+               myOutputTable;
+            string hashString = BlueDataUtility.rowToString(GroupByStream.getRepRow(dp), myGroupByCols);
+            IBlueRow currMaxRow = myOutputTable.getRow(hashString);
+            IBlueRow maxRow = BlueDataUtility.computeMaxRow(dp.deletedRows, myOutputColumn);
+            if (maxRow != null) {
+                bts.Log.assert(currMaxRow != null);
+                bts.Log.assert(BlueDataUtility.compareRows(maxRow, currMaxRow, myOutputColumn) <= 0);
+                if (BlueDataUtility.compareRows(maxRow, currMaxRow, myOutputColumn) == 0) {
+                    maxRow = BlueDataUtility.computeMaxRow(dp.newRows, myOutputColumn);
+                    if (maxRow == null)
+                        myOutputTable.removeRow(hashString);
+                    else
+                        myOutputTable.addRow(maxRow, hashString);
+                }
+            }
+            maxRow = BlueDataUtility.computeMaxRow(dp.addedRows, myOutputColumn);
+            // if the row was replaced in the above lines, then currMaxRow < maxRow, so the if below would never return a true,
+            // otherwise if maxRow > currMaxRow then its replaced
+            if (maxRow != null && (currMaxRow == null || BlueDataUtility.compareRows(maxRow, currMaxRow, myOutputColumn) > 0))
+                myOutputTable.addRow(maxRow, hashString);
+            return myProject(myOutputTable.getRow(hashString));
+        }
+    }
+}
@@ -1,20 +1,15 @@
-// using System;
+using System;

-// namespace BCG
-// {
-// 	public class MaxStream : ViewStream
-// 	{
-//       public MaxStream(ViewStream stream, string outputCol, string inputCols) : this(stream, outputCol, inputCols.Split(' '))
-//       {
-//       }
-// 		public MaxStream (ViewStream stream, string outputCol, string[] inputCols)
-// 		{
-//          mySetRealSource (new GroupByStream (stream, 
-//                                              new MaxGroupByEvaluator (outputCol, inputCols)));
-// 		}
+namespace BCG {
+    public class MaxStream : ViewStream {
+        public MaxStream(ViewStream stream, string outputCol, string inputCols) : this(stream, outputCol, inputCols.Split(' ')) {
+        }
+        public MaxStream(ViewStream stream, string outputCol, string[] inputCols) {
+            mySetRealSource(new GroupByStream(stream,
+                                                new MaxGroupByEvaluator(outputCol, inputCols)));
+        }

-//       public MaxStream (ViewStream stream, string outputCol)
-//          : this (new AddColumnsStream (stream, "fakeCol=0"), outputCol, new string[]{"fakeCol"})
-//       {}
-// 	}
-// }
+        public MaxStream(ViewStream stream, string outputCol)
+           : this(new AddColumnsStream(stream, "fakeCol=0"), outputCol, new string[] { "fakeCol" }) { }
+    }
+}
@@ -1,40 +1,36 @@
-// using System;
-// using BCG.Utilities;
+using System;

-// namespace BCG
-// {
-//    public class MinGroupByEvaluator : MaxGroupByEvaluator
-//    {
-//       public MinGroupByEvaluator (string outputCol, string[] groupByCols) 
-//          : base (outputCol, groupByCols)  {}
+using BCG.Utilities;

-//       public MinGroupByEvaluator (string colMapEpression, string outputCol, string[] groupByCols) :
-//          base (colMapEpression, outputCol, groupByCols)  {}
+namespace BCG {
+    public class MinGroupByEvaluator : MaxGroupByEvaluator {
+        public MinGroupByEvaluator(string outputCol, string[] groupByCols)
+           : base(outputCol, groupByCols) { }

-//       public override IBlueRow evaluate (DataPacket dp)  
-//       {
-//          myOutputTable = myOutputTable == null ? new GroupByOutputTable (dp.schema) : myOutputTable;
-//          string stringRep = BlueDataUtility.rowToString (GroupByStream.getRepRow (dp), myGroupByCols);
-//          IBlueRow currMinRow = myOutputTable.getRow (stringRep);
-//          IBlueRow minRow = BlueDataUtility.computeMinRow (dp.deletedRows, myOutputColumn);
-//          if (minRow != null)
-//          {
-//             // BlueEventLog.logAssert (currMinRow != null);
-//             // BlueEventLog.logAssert (BlueDataUtility.compareRows (minRow, currMinRow, myOutputColumn) >= 0);
-//             if (BlueDataUtility.compareRows (minRow, currMinRow, myOutputColumn) == 0)
-//             {
-//                minRow = BlueDataUtility.computeMinRow (dp.newRows, myOutputColumn);
-//                if (minRow == null)
-//                   myOutputTable.removeRow (stringRep);
-//                else
-//                   myOutputTable.addRow (minRow, stringRep);
-//             }
-//          }
-//          minRow = BlueDataUtility.computeMinRow (dp.addedRows, myOutputColumn);
-//          if (minRow != null && (currMinRow == null || BlueDataUtility.compareRows (minRow, currMinRow, myOutputColumn) < 0))
-//             myOutputTable.addRow (minRow, stringRep);
-//          return myOutputTable.getRow (stringRep);
-//       }
+        public MinGroupByEvaluator(string colMapEpression, string outputCol, string[] groupByCols) :
+           base(colMapEpression, outputCol, groupByCols) { }

-//    }
-// }
+        public override IBlueRow evaluate(DataPacket dp) {
+            myOutputTable = myOutputTable == null ? new GroupByOutputTable(dp.schema) : myOutputTable;
+            string stringRep = BlueDataUtility.rowToString(GroupByStream.getRepRow(dp), myGroupByCols);
+            IBlueRow currMinRow = myOutputTable.getRow(stringRep);
+            IBlueRow minRow = BlueDataUtility.computeMinRow(dp.deletedRows, myOutputColumn);
+            if (minRow != null) {
+                // BlueEventLog.logAssert (currMinRow != null);
+                // BlueEventLog.logAssert (BlueDataUtility.compareRows (minRow, currMinRow, myOutputColumn) >= 0);
+                if (BlueDataUtility.compareRows(minRow, currMinRow, myOutputColumn) == 0) {
+                    minRow = BlueDataUtility.computeMinRow(dp.newRows, myOutputColumn);
+                    if (minRow == null)
+                        myOutputTable.removeRow(stringRep);
+                    else
+                        myOutputTable.addRow(minRow, stringRep);
+                }
+            }
+            minRow = BlueDataUtility.computeMinRow(dp.addedRows, myOutputColumn);
+            if (minRow != null && (currMinRow == null || BlueDataUtility.compareRows(minRow, currMinRow, myOutputColumn) < 0))
+                myOutputTable.addRow(minRow, stringRep);
+            return myOutputTable.getRow(stringRep);
+        }
+
+    }
+}
@@ -1,17 +1,13 @@
-// using System;
+using System;

-// namespace BCG
-// {
-//    public class MinStream : ViewStream
-//    {
-//       public MinStream (ViewStream stream, string outputCol, string[] inputCol)
-//       {
-//          mySetRealSource (new GroupByStream (stream, 
-//                            new MinGroupByEvaluator (outputCol, inputCol)));
-//       }
+namespace BCG {
+    public class MinStream : ViewStream {
+        public MinStream(ViewStream stream, string outputCol, string[] inputCol) {
+            mySetRealSource(new GroupByStream(stream,
+                              new MinGroupByEvaluator(outputCol, inputCol)));
+        }

-//       public MinStream (ViewStream stream, string outputCol)
-//                      : this (new AddColumnsStream (stream, "fakeCol=0"), outputCol, new string[]{"fakeCol"})
-//       {}
-//    }
-// }
+        public MinStream(ViewStream stream, string outputCol)
+                       : this(new AddColumnsStream(stream, "fakeCol=0"), outputCol, new string[] { "fakeCol" }) { }
+    }
+}
@@ -1,94 +1,82 @@
-// using System;
+using System;

-// namespace BCG
-// {
-//    /// <summary>
-//    /// Computes the sum for a given column
-//    /// </summary>
-//    public class SumGroupByEvaluator : GroupByEvaluator
-//    {
-//       public SumGroupByEvaluator (string outputCol, string[] groupByCols) : base (outputCol, groupByCols)
-//       {}
+namespace BCG {
+    /// <summary>
+    /// Computes the sum for a given column
+    /// </summary>
+    public class SumGroupByEvaluator : GroupByEvaluator {
+        public SumGroupByEvaluator(string outputCol, string[] groupByCols) : base(outputCol, groupByCols) { }

-//       public SumGroupByEvaluator (string colMapEpression, string outputCol, string[] groupByCols)
-//          : base (colMapEpression, outputCol, groupByCols)   {}
+        public SumGroupByEvaluator(string colMapEpression, string outputCol, string[] groupByCols)
+           : base(colMapEpression, outputCol, groupByCols) { }

-//       public override IBlueRow evaluate (DataPacket dp)  
-//       {
-//          myOutputTable = myOutputTable == null ? new GroupByOutputTable (dp.schema) : myOutputTable;
-         
-//          IBlueRow sumRow = BlueDataUtility.computeSum(dp.newRows, myOutputColumn);
-//          return sumRow;
-//       }
-//    }
+        public override IBlueRow evaluate(DataPacket dp) {
+            myOutputTable = myOutputTable == null ? new GroupByOutputTable(dp.schema) : myOutputTable;
+
+            IBlueRow sumRow = BlueDataUtility.computeSum(dp.newRows, myOutputColumn);
+            return sumRow;
+        }
+    }


-//    public class MultiColumnSumGroupByEvaluator : IGroupByEvaluator
-//    {
-//       private string[] myOutputCols, myGroupByCols;
-//       public MultiColumnSumGroupByEvaluator(string spaceSeperatedOutputCols, string spaceSeperatedGroupByCols)
-//       {
-//          myOutputCols = spaceSeperatedOutputCols.Split(' ');
-//          myGroupByCols = spaceSeperatedGroupByCols.Split(' ');
-//       }
+    public class MultiColumnSumGroupByEvaluator : IGroupByEvaluator {
+        private string[] myOutputCols, myGroupByCols;
+        public MultiColumnSumGroupByEvaluator(string spaceSeperatedOutputCols, string spaceSeperatedGroupByCols) {
+            myOutputCols = spaceSeperatedOutputCols.Split(' ');
+            myGroupByCols = spaceSeperatedGroupByCols.Split(' ');
+        }

-//       public MultiColumnSumGroupByEvaluator(string[] output_columns, string[] groupby_columns)
-//       {
-//          myOutputCols = output_columns;
-//          myGroupByCols = groupby_columns;
-//       }
+        public MultiColumnSumGroupByEvaluator(string[] output_columns, string[] groupby_columns) {
+            myOutputCols = output_columns;
+            myGroupByCols = groupby_columns;
+        }

-//       #region IGroupByEvaluator Members
+        #region IGroupByEvaluator Members

-//       public IBlueRow evaluate(DataPacket packet)  {return BlueDataUtility.computeSum(packet.newRows, myOutputCols);}
+        public IBlueRow evaluate(DataPacket packet) { return BlueDataUtility.computeSum(packet.newRows, myOutputCols); }

-//       public string[] groupByColumns { get { return myGroupByCols; } }
+        public string[] groupByColumns { get { return myGroupByCols; } }

-//       public void clear()  {/*stateless*/}
+        public void clear() {/*stateless*/}

-//       public IBlueTableSchema getOutputSchema(IBlueTableSchema schema)  {return schema;}
+        public IBlueTableSchema getOutputSchema(IBlueTableSchema schema) { return schema; }

-//       #endregion
-//    }
+        #endregion
+    }

-//    public class SumGroupByEvaluator<T> : GroupByEvaluator
-//    {
-//       public SumGroupByEvaluator(string outputCol, string[] groupByCols)
-//          : base(outputCol, groupByCols)
-//       { }
+    public class SumGroupByEvaluator<T> : GroupByEvaluator {
+        public SumGroupByEvaluator(string outputCol, string[] groupByCols)
+           : base(outputCol, groupByCols) { }

-//       public SumGroupByEvaluator(string colMapEpression, string outputCol, string[] groupByCols)
-//          : base(colMapEpression, outputCol, groupByCols) { }
+        public SumGroupByEvaluator(string colMapEpression, string outputCol, string[] groupByCols)
+           : base(colMapEpression, outputCol, groupByCols) { }

-//       public override IBlueRow evaluate(DataPacket dp)
-//       {
-//          myOutputTable = myOutputTable == null ? new GroupByOutputTable(dp.schema) : myOutputTable;
+        public override IBlueRow evaluate(DataPacket dp) {
+            myOutputTable = myOutputTable == null ? new GroupByOutputTable(dp.schema) : myOutputTable;

-//          IBlueRow sumRow = BlueDataUtility.computeSum<T>(dp.newRows, myOutputColumn);
-//          return sumRow;
-//       }
-//    }
+            IBlueRow sumRow = BlueDataUtility.computeSum<T>(dp.newRows, myOutputColumn);
+            return sumRow;
+        }
+    }

-//    public class MultiColumnSumGroupByEvaluator<T> : IGroupByEvaluator
-//    {
-//       private string[] myOutputCols, myGroupByCols;
-//       public MultiColumnSumGroupByEvaluator(string spaceSeperatedOutputCols, string spaceSeperatedGroupByCols)
-//       {
-//          myOutputCols = spaceSeperatedOutputCols.Split(' ');
-//          myGroupByCols = spaceSeperatedGroupByCols.Split(' ');
-//       }
+    public class MultiColumnSumGroupByEvaluator<T> : IGroupByEvaluator {
+        private string[] myOutputCols, myGroupByCols;
+        public MultiColumnSumGroupByEvaluator(string spaceSeperatedOutputCols, string spaceSeperatedGroupByCols) {
+            myOutputCols = spaceSeperatedOutputCols.Split(' ');
+            myGroupByCols = spaceSeperatedGroupByCols.Split(' ');
+        }

-//       #region IGroupByEvaluator Members
+        #region IGroupByEvaluator Members

-//       public IBlueRow evaluate(DataPacket packet)  {return BlueDataUtility.computeSum<T>(packet.newRows, myOutputCols);}
+        public IBlueRow evaluate(DataPacket packet) { return BlueDataUtility.computeSum<T>(packet.newRows, myOutputCols); }

-//       public string[] groupByColumns { get { return myGroupByCols; } }
+        public string[] groupByColumns { get { return myGroupByCols; } }

-//       public void clear()  {/*stateless*/}
+        public void clear() {/*stateless*/}

-//       public IBlueTableSchema getOutputSchema(IBlueTableSchema schema)  {return schema;}
+        public IBlueTableSchema getOutputSchema(IBlueTableSchema schema) { return schema; }

-//       #endregion
-//    }
+        #endregion
+    }

-// }
+}
@@ -1,107 +1,89 @@
-// using System;
-// using System.Collections.Generic;
+using System;
+using System.Collections.Generic;

-// namespace BCG
-// {
-//    public class NullMapper : IStreamMapper
-//    {
-//       private Dictionary<string, bool> _valid_cols = new Dictionary<string, bool>();
+namespace BCG {
+    public class NullMapper : IStreamMapper {
+        private Dictionary<string, bool> _valid_cols = new Dictionary<string, bool>();

-//       public NullMapper(string[] valid_cols)
-//       {
-//          foreach (string c in valid_cols)
-//             _valid_cols[c] = true;
-//          _valid_cols["id"] = true;
-//       }
+        public NullMapper(string[] valid_cols) {
+            foreach (string c in valid_cols)
+                _valid_cols[c] = true;
+            _valid_cols["id"] = true;
+        }

-//       public IBlueTableSchema getOutputSchema(IBlueTableSchema input_schema) { return input_schema; }
+        public IBlueTableSchema getOutputSchema(IBlueTableSchema input_schema) { return input_schema; }

-//       public IBlueRow map(IBlueRow row)
-//       {
-//          MutableBlueRow out_row = new MutableBlueRow(row);
-//          foreach (string c in row.schema.columnNames)
-//             if (!_valid_cols.ContainsKey(c))
-//                out_row.setValue(c, DBNull.Value);
-//          return out_row;
-//       }
-//    }
+        public IBlueRow map(IBlueRow row) {
+            MutableBlueRow out_row = new MutableBlueRow(row);
+            foreach (string c in row.schema.columnNames)
+                if (!_valid_cols.ContainsKey(c))
+                    out_row.setValue(c, DBNull.Value);
+            return out_row;
+        }
+    }

-//    public class SumStream : ViewStream
-//    {
-//       public SumStream(ViewStream stream, string spaceSeparatedOutputCols, string spaceSeparatedGroupByCols)
-//       {
-//          string[] outputCols = spaceSeparatedOutputCols.Split(' ');
-//          string[] groupByCols = spaceSeparatedGroupByCols.Split(' ');
-//          mySetRealSource(new GroupByStream(stream,
-//                                            outputCols.Length == 1 ? new SumGroupByEvaluator(outputCols[0], groupByCols) as IGroupByEvaluator :
-//                                            new MultiColumnSumGroupByEvaluator(spaceSeparatedOutputCols, spaceSeparatedGroupByCols)));
-//       }
+    public class SumStream : ViewStream {
+        public SumStream(ViewStream stream, string spaceSeparatedOutputCols, string spaceSeparatedGroupByCols) {
+            string[] outputCols = spaceSeparatedOutputCols.Split(' ');
+            string[] groupByCols = spaceSeparatedGroupByCols.Split(' ');
+            mySetRealSource(new GroupByStream(stream,
+                                              outputCols.Length == 1 ? new SumGroupByEvaluator(outputCols[0], groupByCols) as IGroupByEvaluator :
+                                              new MultiColumnSumGroupByEvaluator(spaceSeparatedOutputCols, spaceSeparatedGroupByCols)));
+        }

-//       public SumStream(ViewStream stream, string[] output_columns)
-//       {
-//          ViewStream rs = new AddColumnsStream(stream, "fake_col=0");
-//          rs = new SumStream(rs, output_columns, new string[] { "fake_col" }, false);
-//          rs = new ProjectStream(rs, "!fake_col");
-//          mySetRealSource(rs);
-//       }
+        public SumStream(ViewStream stream, string[] output_columns) {
+            ViewStream rs = new AddColumnsStream(stream, "fake_col=0");
+            rs = new SumStream(rs, output_columns, new string[] { "fake_col" }, false);
+            rs = new ProjectStream(rs, "!fake_col");
+            mySetRealSource(rs);
+        }

-//       public SumStream(ViewStream stream, string space_seperated_output_columns, string space_seperated_groupby_columns, bool force_null_into_other_columns)
-//       {
-//          string[] output_columns = space_seperated_output_columns.Split(' ');
-//          string[] groupby_columns = String.IsNullOrEmpty (space_seperated_groupby_columns) ? new string[]{} : space_seperated_groupby_columns.Split (' ');
-//          mySetRealSource (new SumStream (stream, output_columns, groupby_columns, force_null_into_other_columns));
-//       }
+        public SumStream(ViewStream stream, string space_seperated_output_columns, string space_seperated_groupby_columns, bool force_null_into_other_columns) {
+            string[] output_columns = space_seperated_output_columns.Split(' ');
+            string[] groupby_columns = String.IsNullOrEmpty(space_seperated_groupby_columns) ? new string[] { } : space_seperated_groupby_columns.Split(' ');
+            mySetRealSource(new SumStream(stream, output_columns, groupby_columns, force_null_into_other_columns));
+        }

-//       public SumStream(ViewStream stream, string[] output_columns, string[] groupby_columns, bool force_null_into_other_columns)
-//       {
-//          ViewStream rs = null;
-//          groupby_columns = groupby_columns ?? new string[] {};
-//          if (groupby_columns.Length == 0)
-//          {
-//             rs = new AddColumnsStream(stream, "fake_col=0");
-//             rs = new GroupByStream(rs, new MultiColumnSumGroupByEvaluator(output_columns, new string[] {"fake_col"}));
-//             rs = new ProjectStream(rs, "!fake_col");
-//          }
-//          else
-//          {
-//             rs = new GroupByStream(stream, new MultiColumnSumGroupByEvaluator(output_columns, groupby_columns));
-//          }
-//          if (force_null_into_other_columns)
-//          {
-//             List<string> valid_cols = new List<string>(output_columns);
-//             valid_cols.AddRange(groupby_columns);
-//             rs = new MapStream(rs, new NullMapper(valid_cols.ToArray()));
-//          }
-//          mySetRealSource(rs);
-//       }
+        public SumStream(ViewStream stream, string[] output_columns, string[] groupby_columns, bool force_null_into_other_columns) {
+            ViewStream rs = null;
+            groupby_columns = groupby_columns ?? new string[] { };
+            if (groupby_columns.Length == 0) {
+                // rs = new AddColumnsStream(stream, "fake_col=0");
+                // rs = new GroupByStream(rs, new MultiColumnSumGroupByEvaluator(output_columns, new string[] { "fake_col" }));
+                // rs = new ProjectStream(rs, "!fake_col");
+            } else {
+                rs = new GroupByStream(stream, new MultiColumnSumGroupByEvaluator(output_columns, groupby_columns));
+            }
+            if (force_null_into_other_columns) {
+                List<string> valid_cols = new List<string>(output_columns);
+                valid_cols.AddRange(groupby_columns);
+                rs = new MapStream(rs, new NullMapper(valid_cols.ToArray()));
+            }
+            mySetRealSource(rs);
+        }

-//    public SumStream (ViewStream stream, string outputCol)
-//    : this (new AddColumnsStream (stream, "fakeCol=0"), outputCol, "fakeCol")
-//    {
-//    }
-// }
+        public SumStream(ViewStream stream, string outputCol)
+        : this(new AddColumnsStream(stream, "fakeCol=0"), outputCol, "fakeCol") {
+        }
+    }

-// public class IntSumStream : ViewStream
-// {
-//    public IntSumStream (ViewStream stream, string spaceSeparatedOutputCols, string spaceSeparatedGroupByCols)
-//    {
-//       string[] outputCols = spaceSeparatedOutputCols.Split(' ');
-//       string[] groupByCols = spaceSeparatedGroupByCols.Split(' ');
-//       mySetRealSource(new GroupByStream(stream,
-//                                         outputCols.Length == 1 ? new SumGroupByEvaluator<int>(outputCols[0], groupByCols) as IGroupByEvaluator:
-//                                         new MultiColumnSumGroupByEvaluator<int>(spaceSeparatedOutputCols, spaceSeparatedGroupByCols)));
-//    }
+    public class IntSumStream : ViewStream {
+        public IntSumStream(ViewStream stream, string spaceSeparatedOutputCols, string spaceSeparatedGroupByCols) {
+            string[] outputCols = spaceSeparatedOutputCols.Split(' ');
+            string[] groupByCols = spaceSeparatedGroupByCols.Split(' ');
+            mySetRealSource(new GroupByStream(stream,
+                                              outputCols.Length == 1 ? new SumGroupByEvaluator<int>(outputCols[0], groupByCols) as IGroupByEvaluator :
+                                              new MultiColumnSumGroupByEvaluator<int>(spaceSeparatedOutputCols, spaceSeparatedGroupByCols)));
+        }

-// }
+    }


-//    public class SumStream<T> : ViewStream
-//    {
-//       public SumStream(ViewStream stream, string outputCol, string spaceSeparatedInputCols)
-//       {
-//          string[] inputCols = spaceSeparatedInputCols.Split(' ');
-//          mySetRealSource(new GroupByStream(stream,
-//                                              new SumGroupByEvaluator<T>(outputCol, inputCols)));
-//       }
-//    }
-// }
+    public class SumStream<T> : ViewStream {
+        public SumStream(ViewStream stream, string outputCol, string spaceSeparatedInputCols) {
+            string[] inputCols = spaceSeparatedInputCols.Split(' ');
+            mySetRealSource(new GroupByStream(stream,
+                                                new SumGroupByEvaluator<T>(outputCol, inputCols)));
+        }
+    }
+}
@@ -0,0 +1,79 @@
+using BCG;
+
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+using ZstdSharp.Unsafe;
+
+namespace bts {
+    public class RowDiffStream : ViewStream {
+        private ViewStream _vs;
+        private readonly string _order_col, _col_1, _col_2;
+        private readonly int _diff;
+        private IBlueTableSchema _out_schema;
+        private readonly string _diff_col_name;
+        public RowDiffStream(ViewStream vs, string order_col, string col_1, string col_2, int diff, string diff_col_name) {
+            _vs = vs;
+            _order_col = order_col;
+            _col_1 = col_1;
+            _col_2 = col_2;
+            _diff = diff;
+            _diff_col_name = diff_col_name;
+        }
+
+        private string _diff_col_name_perc {
+            get {
+                return $"{_diff_col_name}_percentage";
+            }
+        }
+
+        protected override void myOnFirstSubscriber() {
+            _vs.onChange += _handle_vs;
+        }
+
+        protected override void myOnLastSubscriber() {
+            _vs.onChange -= _handle_vs;
+        }
+
+        private void _handle_vs(object dp_obj) {
+            var dp = dp_obj as DataPacket;
+            IBlueRowCollection nrows = dp.newRows;
+            _out_schema = BlueDataUtility.add_column(nrows.schema, _diff_col_name, typeof(double));
+            _out_schema = BlueDataUtility.add_column(_out_schema, _diff_col_name_perc, typeof(double));
+            List<IBlueRow> row_list = new List<IBlueRow>();
+            foreach (IBlueRow r in nrows)
+                row_list.Add(r);
+            //OrderBy sorts in ascedning order
+            var sorted_rows = row_list.OrderBy(r => r[_order_col]).ToList();
+            var sorted_row_array = sorted_rows.ToArray();
+            // reverse it to make it descending    
+            sorted_rows.Reverse();
+            //sort rows so we can do the diff
+            OrderedBlueTable rv = new OrderedBlueTable(_out_schema);
+            int i = 0;
+            foreach (IBlueRow r in sorted_rows) {
+                MutableBlueRow nr = new MutableBlueRow(_out_schema, r);
+                //So, in the expression "x - y," where y is subtracted from x, x is the minuend, and y is the subtrahend.
+                // we assume x - y, and name variables like that
+                double x = r.get<double>(_col_1);
+                int y_row_idx = i + _diff;
+                double diff = System.Double.NaN;
+                double perc = System.Double.NaN;
+                if (y_row_idx < sorted_rows.Count()) {
+                    var y = sorted_rows[y_row_idx].get<double>(_col_2);
+                    diff = x - y;
+                    perc = 100.0 * diff / y;
+                }
+                nr.setValue(_diff_col_name, diff);
+                nr.setValue(_diff_col_name_perc, perc);
+                rv.addRow(nr);
+                i++;
+            }
+
+            var dp_out = BlueDataUtility.build_dp_inc(new_rows: rv, myLastValue as DataPacket, true);
+            myFireEvent(dp_out);
+
+        }
+    }
+}
@@ -0,0 +1,203 @@
+namespace Bts.DataStream;
+
+using BCG;
+
+using bts;
+
+using Bts.DataStreamCore;
+
+using mbts;
+
+using MongoDB.Bson;
+using MongoDB.Driver;
+
+using Spark.Core.Disposables;
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Reactive.Subjects;
+using System.Threading;
+using System.Threading.Tasks;
+
+public class MongoCollectionStream : ViewStream, IObservable<DataPacket> {
+   readonly string collectionName;
+   readonly string databaseName;
+   readonly string url;
+   readonly object syncRoot = new();
+   readonly CancellationTokenSource cts = new();
+   readonly Subject<DataPacket> subject = new();
+
+   bool hasStarted = false;
+   IBlueRowFactory<BsonDocument>? rowFactory;
+   MongoClient? clientBacking;
+   IMongoDatabase? databaseBacking;
+   IMongoCollection<BsonDocument>? collectionBacking = null;
+   BlueTableImmutable? table = null;
+
+   public MongoCollectionStream()
+      : this(
+         Environment.GetEnvironmentVariable("MONGO_DB_COLL") ?? string.Empty,
+         Environment.GetEnvironmentVariable("MONGO_DB_NAME") ?? string.Empty,
+         Environment.GetEnvironmentVariable("MONGO_DB_URL") ?? string.Empty) {
+   }
+
+   public MongoCollectionStream(string collectionName)
+      : this(
+         collectionName,
+         Environment.GetEnvironmentVariable("MONGO_DB_NAME") ?? string.Empty,
+         Environment.GetEnvironmentVariable("MONGO_DB_URL") ?? string.Empty) {
+   }
+
+   public MongoCollectionStream(string collectionName, string databaseName)
+      : this(
+         collectionName,
+         databaseName,
+         Environment.GetEnvironmentVariable("MONGO_DB_URL") ?? string.Empty) {
+   }
+
+   public MongoCollectionStream(string collectionName, string databaseName, string url)
+      : this(collectionName, databaseName, url, null) { }
+
+   internal MongoCollectionStream(
+      string collectionName, string databaseName, string url, IBlueRowFactory<BsonDocument>? rowFactory) {
+      this.collectionName = collectionName;
+      this.databaseName = databaseName;
+      this.url = url;
+      this.rowFactory = rowFactory;
+      mySetRealSource(new ObservableViewStream(this));
+   }
+
+   MongoClient client => clientBacking ??= new(url);
+   IMongoDatabase database => databaseBacking ??= client.GetDatabase(databaseName);
+   IMongoCollection<BsonDocument>? collection {
+      get => Volatile.Read(ref collectionBacking);
+      set => Volatile.Write(ref collectionBacking, value);
+   }
+
+   public IDisposable Subscribe(IObserver<DataPacket> observer) {
+      lock (syncRoot) {
+         if (hasStarted) {
+            if (table is not null) {
+               // The first update has already been fired. Seed observer w/ current state.
+               observer.OnNext(new DataPacket(table, table, new BlueTable(table.schema)));
+            }
+            return subject.Subscribe(observer);
+         }
+         hasStarted = true;
+      }
+      var subscription = subject.Subscribe(observer);
+      // Retrieve collection snapshot to bootstrap sequence
+      initTable().ignore();
+      // Watch changes
+      Task.Run(watchChanges);
+      return Disposable.Create(Dispose);
+
+      void Dispose() {
+         Log.Gen.info("Disposing MongoDbChangeObservable subscription");
+         subscription.Dispose();
+         cts.Cancel();
+         cts.Dispose();
+      }
+   }
+
+   protected virtual IBlueRowFactory<BsonDocument> getRowFactory(IEnumerable<BsonDocument> docs) =>
+      MongoSchemaAdaptor.InferSchema(docs);
+
+   async Task watchChanges() {
+      Log.Gen.info(
+         $"MongoCollectionStreamSource. Watching changes. thread: {Environment.CurrentManagedThreadId}");
+      while (collection is null) {
+         await Task.Delay(100);
+      }
+      Log.notnull(collection);
+      using var cursor = collection.Watch(new ChangeStreamOptions {
+         FullDocument = ChangeStreamFullDocumentOption.UpdateLookup
+      });
+      try {
+         while (await cursor.MoveNextAsync(cts.Token)) {
+            // Ignore while waiting for init
+            lock (syncRoot) {
+               if (table is null) {
+                  continue;
+               }
+            }
+            // schemaAdaptor is initialized after table; redundantly assert both
+            // are non-null to be safe, and clarify expectations.
+            Log.notnull(rowFactory);
+            Log.notnull(table);
+
+            var bd = table.ToDataPacketBuilder();
+            foreach (var ch in cursor.Current) {
+               var opDescJson = ch.OperationDescription?.ToJson() ?? string.Empty;
+               var updDescJson = ch.UpdateDescription?.ToJson() ?? string.Empty;
+               Log.Gen.info(
+                  $"MongoCollectionStream.watchChanges. Doc changed. type: {ch.OperationType} " +
+                  $"changes:\n\t\t{updDescJson}");
+               switch (ch.OperationType) {
+                  case ChangeStreamOperationType.Insert: {
+                        bd.AddOrUpdate(Row());
+                        break;
+                     }
+                  case ChangeStreamOperationType.Update: {
+                        bd.Remove(OldRow().Id());
+                        bd.AddOrUpdate(Row());
+                        break;
+                     }
+                  case ChangeStreamOperationType.Replace: {
+                        bd.Remove(OldRow().Id());
+                        bd.AddOrUpdate(Row());
+                        break;
+                     }
+                  case ChangeStreamOperationType.Delete: {
+                        bd.Remove(OldRow().Id());
+                        break;
+                     }
+                  default:
+                     Log.assert(false, $"Unsupported op type '{ch.OperationType}'");
+                     break;
+               }
+
+               IBlueRow Row() =>
+                  rowFactory.GetBlueRow(ch.FullDocumentBeforeChange);
+
+               IBlueRow OldRow() =>
+                  rowFactory.GetBlueRow(ch.FullDocumentBeforeChange);
+            }
+            var dp = bd.ToDataPacket();
+            if (!dp.HasChanges()) {
+               Log.Gen.warn(
+                  $"MongoDbChangeObservable Ignoring update because it didn't change any rows.");
+               continue;
+            }
+            lock (syncRoot) {
+               table = (BlueTableImmutable)dp.newRows;
+               subject.OnNext(dp);
+            }
+         }
+      } catch (TaskCanceledException ex) {
+         Log.Gen.warn(
+            $"MongoDbChangeObservable 'Watch' task cancelled (this is " +
+            $"expected if subscription was disposed). {ex}");
+      }
+   }
+
+
+   [MemberNotNull(nameof(collection))]
+   async Task initTable() {
+      collection = database.GetCollection<BsonDocument>(collectionName);
+      var cursor = collection.Find(Builders<BsonDocument>.Filter.Empty).ToCursor();
+      var docList = await cursor.ToListAsync();
+      rowFactory ??= MongoSchemaAdaptor.InferSchema(docList);
+      var firstTable = new BlueTableImmutable(rowFactory.Schema).ToDataPacketBuilder();
+      foreach (var doc in docList) {
+         var row = rowFactory.GetBlueRow(doc);
+         firstTable.AddOrUpdate(row);
+      }
+      var dp = firstTable.ToDataPacket();
+      lock (syncRoot) {
+         table = (BlueTableImmutable)dp.newRows;
+         subject.OnNext(dp);
+      }
+   }
+}
@@ -1,212 +1,210 @@
-using System;
-using System.Collections.Generic;
-using MongoDB.Driver;
-using MongoDB.Bson;
-using BCG;
+namespace BCG;
+
 using BCG.Utilities.General;
-using ZstdSharp.Unsafe;
-using System.Runtime.CompilerServices;
+
 using mbts.spark;

+using MongoDB.Bson;
+using MongoDB.Driver;

-namespace BCG {
-    [DataStreamUserRespresentation("mongodb_sql")]
-    public class MongoDBSQLStream : ViewStream, IWorker {
-        private ViewStreamDatabase _vsd;
-        private readonly string _connection_string, _db_name, _collection_name;
-        private MongoClient _client;
-        private BlueTable _table;
+using System;
+using System.Collections.Generic;

-        // Access the database
-        private IMongoDatabase _database;
-        private IDictionary<string, int> _id_map = new Dictionary<string, int>();
-        // mongodb://192.168.1.80:27017
+[DataStreamUserRespresentation("mongodb_sql")]
+public class MongoDBSQLStream : ViewStream, IWorker {
+   private ViewStreamDatabase _vsd;
+   private readonly string _connection_string, _db_name, _collection_name;
+   private MongoClient _client;
+   private BlueTable _table;

-        public MongoDBSQLStream(string connection_string, string db_name, string collection_name)
-        : this(connection_string, db_name, collection_name, ViewStreamDatabase.instance) {
+   // Access the database
+   private IMongoDatabase _database;
+   private IDictionary<string, int> _id_map = new Dictionary<string, int>();
+   // mongodb://192.168.1.80:27017

-        }
-        public MongoDBSQLStream(string connection_string, string db_name, string collection_name, ViewStreamDatabase vsd) {
-            bts.Log.Gen.info($"MongoDBStream constructed connection_string: {connection_string} " +
-                                    $"db_name: {db_name}");
-            _connection_string = connection_string;
-            _db_name = db_name;
-            _collection_name = collection_name;
-            _vsd = vsd;
-            _client = new MongoClient(_connection_string);
-            _database = _client.GetDatabase(_db_name);
-        }
+   public MongoDBSQLStream(string connection_string, string db_name, string collection_name)
+   : this(connection_string, db_name, collection_name, ViewStreamDatabase.instance) {

-        protected override void myOnFirstSubscriber() {
-            MasterWorker.getInstance(false).addWorker(this, TimeSpan.FromSeconds(1));
-        }
+   }
+   public MongoDBSQLStream(string connection_string, string db_name, string collection_name, ViewStreamDatabase vsd) {
+      bts.Log.Gen.info($"MongoDBStream constructed connection_string: {connection_string} " +
+                              $"db_name: {db_name}");
+      _connection_string = connection_string;
+      _db_name = db_name;
+      _collection_name = collection_name;
+      _vsd = vsd;
+      _client = new MongoClient(_connection_string);
+      _database = _client.GetDatabase(_db_name);
+   }

-        protected override void myOnLastSubscriber() {
-            MasterWorker.getInstance(false).removeWorker(this);
-        }
+   protected override void myOnFirstSubscriber() {
+      MasterWorker.getInstance(false).addWorker(this, TimeSpan.FromSeconds(1));
+   }

-        public void doWork() {
-            _read_mogodb();
-        }
+   protected override void myOnLastSubscriber() {
+      MasterWorker.getInstance(false).removeWorker(this);
+   }

-        private void _read_mogodb() {
-            HighPerformanceTimer timer = new HighPerformanceTimer();
-            timer.start();
-            // Access the collection
-            IMongoCollection<BsonDocument> collection = _database.GetCollection<BsonDocument>(name: _collection_name);
+   public void doWork() {
+      _read_mogodb();
+   }

-            // Fetch all documents from the collection
-            var documents = collection.Find(Builders<BsonDocument>.Filter.Empty).ToCursor();
-            _table = _table == null ? null : new BlueTable(_table.schema);
-            // Iterate through the documents and print values
-            foreach (var document in documents.ToEnumerable()) {
-                bts.Log.Gen.info($"document: {document} json: {document.ToJson()}");
-                if (_table == null) {
-                    _init_table(document);
-                }
-                _add_row(document);
-            }
-            timer.stop();
-            bts.Log.Gen.info($"MongoDBStream time to read {_collection_name} {timer.lastIntervalTime} msecs");
-            timer.start();
-            var dp = BlueDataUtility.build_dp_inc(_table, myLastValue == null ? null : myLastValue as DataPacket, true);
-            timer.stop();
-            bts.Log.Gen.info($"MongoDBStream time to compare tables :{timer.lastIntervalTime} msecs");
-            if (dp.addedRows.Count == 0 && dp.deletedRows.Count == 0)
-                return;
-            myFireEvent(dp);
-        }
+   private void _read_mogodb() {
+      HighPerformanceTimer timer = new HighPerformanceTimer();
+      timer.start();
+      // Access the collection
+      IMongoCollection<BsonDocument> collection = _database.GetCollection<BsonDocument>(name: _collection_name);

-        private void _init_table(BsonDocument doc_row) {
-            bts.Log.assert(_table == null);
-            List<ColumnInfo> cis = new List<ColumnInfo>();
-            cis.Add((new ColumnInfo("id", 0, typeof(Int32))));
-            foreach (var n in doc_row.Names) {
-                cis.Add(new ColumnInfo(n, cis.Count, typeof(string)));
-            }
-            IBlueTableSchema schema = new BlueTableSchema(cis.ToArray(), _collection_name);
-            _table = new BlueTable(schema);
-        }
+      // Fetch all documents from the collection
+      var documents = collection.Find(Builders<BsonDocument>.Filter.Empty).ToCursor();
+      _table = _table == null ? null : new BlueTable(_table.schema);
+      // Iterate through the documents and print values
+      foreach (var document in documents.ToEnumerable()) {
+         bts.Log.Gen.info($"document: {document} json: {document.ToJson()}");
+         if (_table == null) {
+            _init_table(document);
+         }
+         _add_row(document);
+      }
+      timer.stop();
+      bts.Log.Gen.info($"MongoDBStream time to read {_collection_name} {timer.lastIntervalTime} msecs");
+      timer.start();
+      var dp = BlueDataUtility.build_dp_inc(_table, myLastValue == null ? null : myLastValue as DataPacket, true);
+      timer.stop();
+      bts.Log.Gen.info($"MongoDBStream time to compare tables :{timer.lastIntervalTime} msecs");
+      if (dp.addedRows.Count == 0 && dp.deletedRows.Count == 0)
+         return;
+      myFireEvent(dp);
+   }

-        private void _add_row(BsonDocument doc) {
-            var key_val = doc["_id"];
-            var key = key_val.ToString();
-            int id;
-            if (!_id_map.TryGetValue(key, out id)) {
-                id = _id_map.Count;
-                _id_map.Add(key, id);
-            }
-            MutableBlueRow nr = new MutableBlueRow(_table.schema);
-            nr.setValue("id", id);
-            foreach (var n in doc.Names) {
-                var val = doc[n].ToString();
-                nr.setValue(n, val);
-            }
-            _table.addRow(nr);
-        }
-    }
+   private void _init_table(BsonDocument doc_row) {
+      bts.Log.assert(_table == null);
+      List<ColumnInfo> cis = new List<ColumnInfo>();
+      cis.Add((new ColumnInfo("id", 0, typeof(Int32))));
+      foreach (var n in doc_row.Names) {
+         cis.Add(new ColumnInfo(n, cis.Count, typeof(string)));
+      }
+      IBlueTableSchema schema = new BlueTableSchema(cis.ToArray(), _collection_name);
+      _table = new BlueTable(schema);
+   }

-    [DataStreamUserRespresentation("mongodb")]
-    public class MongoDBStream : ViewStream, IWorker {
-        private ViewStreamDatabase _vsd;
-        private readonly string _connection_string, _db_name, _collection_name;
-        private MongoClient _client;
-        private BlueTable _table;
+   private void _add_row(BsonDocument doc) {
+      var key_val = doc["_id"];
+      var key = key_val.ToString();
+      int id;
+      if (!_id_map.TryGetValue(key, out id)) {
+         id = _id_map.Count;
+         _id_map.Add(key, id);
+      }
+      MutableBlueRow nr = new MutableBlueRow(_table.schema);
+      nr.setValue("id", id);
+      foreach (var n in doc.Names) {
+         var val = doc[n].ToString();
+         nr.setValue(n, val);
+      }
+      _table.addRow(nr);
+   }
+}

-        // Access the database
-        private IMongoDatabase _database;
-        private IDictionary<string, int> _id_map = new Dictionary<string, int>();
-        // mongodb://192.168.1.80:27017
+[DataStreamUserRespresentation("mongodb")]
+public class MongoDBStream : ViewStream, IWorker {
+   private ViewStreamDatabase _vsd;
+   private readonly string _connection_string, _db_name, _collection_name;
+   private MongoClient _client;
+   private BlueTable _table;

-        public MongoDBStream(string connection_string, string db_name, string collection_name)
-        : this(connection_string, db_name, collection_name, ViewStreamDatabase.instance) {
+   // Access the database
+   private IMongoDatabase _database;
+   private IDictionary<string, int> _id_map = new Dictionary<string, int>();
+   // mongodb://192.168.1.80:27017

-        }
-        public MongoDBStream(string connection_string, string db_name, string collection_name, ViewStreamDatabase vsd) {
-            bts.Log.Gen.info($"MongoDBStream constructed connection_string: {connection_string} " +
-                                    $"db_name: {db_name}");
-            _connection_string = connection_string;
-            _db_name = db_name;
-            _collection_name = collection_name;
-            _vsd = vsd;
-            _client = new MongoClient(_connection_string);
-            _database = _client.GetDatabase(_db_name);
-        }
+   public MongoDBStream(string connection_string, string db_name, string collection_name)
+   : this(connection_string, db_name, collection_name, ViewStreamDatabase.instance) {

-        protected override void myOnFirstSubscriber() {
-            MasterWorker.getInstance(false).addWorker(this, TimeSpan.FromSeconds(1));
-        }
+   }
+   public MongoDBStream(string connection_string, string db_name, string collection_name, ViewStreamDatabase vsd) {
+      bts.Log.Gen.info($"MongoDBStream constructed connection_string: {connection_string} " +
+                              $"db_name: {db_name}");
+      _connection_string = connection_string;
+      _db_name = db_name;
+      _collection_name = collection_name;
+      _vsd = vsd;
+      _client = new MongoClient(_connection_string);
+      _database = _client.GetDatabase(_db_name);
+   }

-        protected override void myOnLastSubscriber() {
-            MasterWorker.getInstance(false).removeWorker(this);
-        }
+   protected override void myOnFirstSubscriber() {
+      MasterWorker.getInstance(false).addWorker(this, TimeSpan.FromSeconds(1));
+   }

-        public void doWork() {
-            _read_mogodb();
-        }
+   protected override void myOnLastSubscriber() {
+      MasterWorker.getInstance(false).removeWorker(this);
+   }

-        private void _read_mogodb() {
-            HighPerformanceTimer timer = new HighPerformanceTimer();
-            timer.start();
-            // Access the collection
-            IMongoCollection<BsonDocument> collection = _database.GetCollection<BsonDocument>(name: _collection_name);
+   public void doWork() {
+      _read_mogodb();
+   }

-            // Fetch all documents from the collection
-            var documents = collection.Find(Builders<BsonDocument>.Filter.Empty).ToCursor();
-            _table = _table == null ? null : new BlueTable(_table.schema);
-            // Iterate through the documents and print values
-            foreach (var document in documents.ToEnumerable()) {
-                bts.Log.Gen.info($"document: {document} json: {document.ToJson()}");
-                if (_table == null) {
-                    _init_table(document);
-                }
-                _add_doc(document);
-            }
-            timer.stop();
-            bts.Log.Gen.info($"MongoDBStream time to read {_collection_name} {timer.lastIntervalTime} msecs");
-            timer.start();
-            var dp = BlueDataUtility.build_dp_inc(_table, myLastValue == null ? null : myLastValue as DataPacket, true);
-            timer.stop();
-            bts.Log.Gen.info($"MongoDBStream time to compare tables :{timer.lastIntervalTime} msecs");
-            if (dp.addedRows.Count == 0 && dp.deletedRows.Count == 0)
-                return;
-            myFireEvent(dp);
-        }
+   private void _read_mogodb() {
+      HighPerformanceTimer timer = new HighPerformanceTimer();
+      timer.start();
+      // Access the collection
+      IMongoCollection<BsonDocument> collection = _database.GetCollection<BsonDocument>(name: _collection_name);

-        private void _init_table(BsonDocument doc_row) {
-            bts.Log.assert(_table == null);
-            var schema = BlueDataUtility.form_schema($"{_database}_{_table}",
-            Tuple.Create("id", TypeCode.Int32),
-            Tuple.Create("doc_id", TypeCode.String),
-            Tuple.Create("key", TypeCode.String),
-            Tuple.Create("value", TypeCode.String));
-            _table = new BlueTable(schema);
-        }
+      // Fetch all documents from the collection
+      var documents = collection.Find(Builders<BsonDocument>.Filter.Empty).ToCursor();
+      _table = _table == null ? null : new BlueTable(_table.schema);
+      // Iterate through the documents and print values
+      foreach (var document in documents.ToEnumerable()) {
+         bts.Log.Gen.info($"document: {document} json: {document.ToJson()}");
+         if (_table == null) {
+            _init_table(document);
+         }
+         _add_doc(document);
+      }
+      timer.stop();
+      bts.Log.Gen.info($"MongoDBStream time to read {_collection_name} {timer.lastIntervalTime} msecs");
+      timer.start();
+      var dp = BlueDataUtility.build_dp_inc(_table, myLastValue == null ? null : myLastValue as DataPacket, true);
+      timer.stop();
+      bts.Log.Gen.info($"MongoDBStream time to compare tables :{timer.lastIntervalTime} msecs");
+      if (dp.addedRows.Count == 0 && dp.deletedRows.Count == 0)
+         return;
+      myFireEvent(dp);
+   }

-        private void _add_doc(BsonDocument doc) {
-            var doc_id_bson = doc["_id"];
-            var doc_id = doc_id_bson.ToString();
-            Func<string, string, int> get_id = (string doc_id, string key) => {
-                string hash_key = $"{doc_id}_{key}";
-                int id = 0;
-                if (!_id_map.TryGetValue(hash_key, out id)) {
-                    id = _id_map.Count;
-                    _id_map.Add(hash_key, id);
-                }
-                return id;
-            };
-            foreach (var n in doc.Names) {
-                string key = n;
-                var id = get_id(doc_id, key);
-                MutableBlueRow nr = new MutableBlueRow(_table.schema);
-                var val = doc[n].ToString();
-                nr.setValue("id", id);
-                nr.setValue("doc_id", doc_id);
-                nr.setValue("key", key);
-                nr.setValue("value", val);
-                _table.addRow(nr);
-            }
-        }
-    }
+   private void _init_table(BsonDocument doc_row) {
+      bts.Log.assert(_table == null);
+      var schema = BlueDataUtility.form_schema($"{_database}_{_table}",
+      Tuple.Create("id", TypeCode.Int32),
+      Tuple.Create("doc_id", TypeCode.String),
+      Tuple.Create("key", TypeCode.String),
+      Tuple.Create("value", TypeCode.String));
+      _table = new BlueTable(schema);
+   }

-}
+   private void _add_doc(BsonDocument doc) {
+      var doc_id_bson = doc["_id"];
+      var doc_id = doc_id_bson.ToString();
+      Func<string, string, int> get_id = (string doc_id, string key) => {
+         string hash_key = $"{doc_id}_{key}";
+         int id = 0;
+         if (!_id_map.TryGetValue(hash_key, out id)) {
+            id = _id_map.Count;
+            _id_map.Add(hash_key, id);
+         }
+         return id;
+      };
+      foreach (var n in doc.Names) {
+         string key = n;
+         var id = get_id(doc_id, key);
+         MutableBlueRow nr = new MutableBlueRow(_table.schema);
+         var val = doc[n].ToString();
+         nr.setValue("id", id);
+         nr.setValue("doc_id", doc_id);
+         nr.setValue("key", key);
+         nr.setValue("value", val);
+         _table.addRow(nr);
+      }
+   }
+}
@@ -0,0 +1,63 @@
+namespace Bts.DataStream;
+
+using MongoDB.Bson;
+
+using System;
+
+public static class MongoDbExtensions {
+   public static BsonArray GetArray(this BsonDocument doc, string elementName) =>
+      doc[elementName].AsBsonArray;
+
+   public static BsonArray? GetArrayOrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsBsonArray ?
+         val.AsBsonArray : null;
+
+   public static string GetString(this BsonDocument doc, string elementName) =>
+      doc[elementName].AsString;
+
+   public static string? GetStringOrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsString ?
+         val.AsString : null;
+
+   public static int GetInt32(this BsonDocument doc, string elementName) =>
+      doc[elementName].AsInt32;
+
+   public static int? GetInt32OrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsInt32 ?
+         val.AsInt32 : null;
+
+   public static long GetInt64(this BsonDocument doc, string elementName) =>
+      doc[elementName].AsInt64;
+
+   public static long? GetInt64OrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsInt64 ?
+         val.AsInt64 : null;
+
+   public static double GetDouble(this BsonDocument doc, string elementName) =>
+      doc[elementName].AsDouble;
+
+   public static double? GetDoubleOrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsDouble ?
+         val.AsDouble : null;
+
+   public static DateTime GetDateTime(this BsonDocument doc, string elementName) =>
+      doc[elementName].ToUniversalTime();
+
+   public static DateTime? GetDateTimeOrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsValidDateTime ?
+         val.ToUniversalTime() : null;
+
+   public static DateTime GetTimestamp(this BsonDocument doc, string elementName) =>
+      doc[elementName].ToUniversalTime();
+
+   public static DateTime? GetTimestampOrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsValidDateTime ?
+         val.ToUniversalTime() : null;
+
+   public static ObjectId GetObjectId(this BsonDocument doc, string elementName) =>
+      doc[elementName].AsObjectId;
+
+   public static ObjectId? GetObjectIdOrDefault(this BsonDocument doc, string elementName) =>
+      doc.TryGetValue(elementName, out var val) && val.IsObjectId ?
+         val.AsObjectId : null;
+}
@@ -0,0 +1,57 @@
+namespace Bts.DataStream;
+
+using BCG;
+
+using bts;
+
+using MongoDB.Bson;
+
+using System;
+using System.Collections.Generic;
+
+public static class MongoSchemaAdaptor {
+   public static BlueTableSchemaAdaptor<BsonDocument> InferSchema(IEnumerable<BsonDocument> docs) {
+      var schemaAdaptor = new BlueTableSchemaAdaptor<BsonDocument>("MongoCollectionStream");
+      foreach (var doc in docs) {
+         foreach (var el in doc) {
+            if (schemaAdaptor.Contains(el.Name)) {
+               continue;
+            }
+            switch (el.Value.BsonType) {
+               case BsonType.Array:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetArrayOrDefault(el.Name)?.ToString() ?? string.Empty);
+                  break;
+               case BsonType.String:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetStringOrDefault(el.Name) ?? string.Empty);
+                  break;
+               case BsonType.Int32:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetInt32OrDefault(el.Name));
+                  break;
+               case BsonType.Int64:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetInt64OrDefault(el.Name));
+                  break;
+               case BsonType.Double:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetDoubleOrDefault(el.Name));
+                  break;
+               case BsonType.DateTime:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetDateTimeOrDefault(el.Name));
+                  break;
+               case BsonType.Timestamp:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetTimestampOrDefault(el.Name));
+                  break;
+               case BsonType.ObjectId:
+                  schemaAdaptor.AddColumn(el.Name, d => d.GetObjectIdOrDefault(el.Name)?.ToString());
+                  break;
+               case BsonType.Null:
+                  Log.Gen.warn(
+                     $"Ignoring column '{el.Name}' because at least one element is null");
+                  break;
+               default:
+                  throw new InvalidOperationException(
+                     $"Unsupported BsonType '{el.Value.BsonType}'");
+            }
+         }
+      }
+      return schemaAdaptor;
+   }
+}
@@ -0,0 +1,34 @@
+using BCG;
+
+namespace bts {
+    public class SchemaGuesserStream : ViewStream {
+
+        private IBlueRowCollection _rows = null;
+        private ViewStream _vs;
+        public SchemaGuesserStream(ViewStream vs) {
+            _vs = vs;
+        }
+
+        protected override void myOnFirstSubscriber() {
+            _vs.onChange += _on_data;
+        }
+        protected override void myOnLastSubscriber() {
+            _vs.onChange -= _on_data;
+        }
+
+        private void _on_data(object obj) {
+            DataPacket dp = obj as DataPacket;
+            if (_rows == null) {
+                _rows = BlueDataUtility.get_typed_table(dp.newRows);
+            }
+            var dp_out = BlueDataUtility.build_dp_inc(_rows, myLastValue as DataPacket);
+            myFireEvent(dp_out);
+
+
+        }
+
+
+
+
+    }
+}
@@ -1,99 +1,99 @@
-using Bts.ColumnSortExpressions;
-
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.Diagnostics.CodeAnalysis;
-
-namespace BCG;
-
-/// <summary>
-/// Defines a Sort stream, with performance of O(n) for all the increments. It uses simple merge sort
-/// to merge the additions to the accumulates table
-/// </summary>
-public class SortStream : ViewStream {
-   ViewStream stream;
-   IList<ColumnSortExpression> sortCols;
-   IComparer? comparer;
-   DataPacket? lastFiredPacket;
-   DataPacket? lastReceivedPacket;
-
-   public SortStream(ViewStream stream, string sortExpression) {
-      this.stream = stream;
-      SortExpression = sortExpression;
-   }
-
-   public SortStream(ViewStream vs, string colName, bool isAsc) {
-      stream = vs;
-      SortExpression = isAsc ? "+" + colName : "-" + colName;
-   }
-
-   public SortStream(ViewStream stream, IComparer comparer) {
-      this.stream = stream;
-      this.comparer = comparer;
-      sortCols = Array.Empty<ColumnSortExpression>();
-   }
-
-   [MemberNotNull(nameof(sortCols))]
-   public string SortExpression {
-      set {
-         comparer = null;
-         lastFiredPacket = null;
-         sortCols = ColumnSortExpressionInterpreter.Evaluate(value);
-         if (lastReceivedPacket is not null) {
-            myChangeHandler(lastReceivedPacket);
-         }
-      }
-   }
-
-   public IComparer Comparer {
-      set {
-         comparer = value;
-         lastFiredPacket = null;
-         if (lastReceivedPacket is not null) {
-            myChangeHandler(lastReceivedPacket);
-         }
-      }
-   }
-
-   public void myChangeHandlerTest(object o) =>
-      myChangeHandler(o);
-
-   [MemberNotNull(nameof(lastFiredPacket))]
-   internal void myChangeHandler(object o) {
-      lastReceivedPacket = (DataPacket)o;
-      // First callback, so we need to sort the whole table, this is the
-      // only time we will do that for all the other sorting operations would
-      // be sorting the increments and inserting them into the whole list
-      if (lastFiredPacket is null) {
-         lastFiredPacket = new() {
-            newRows = comparer is null ?
-               new SortedTable(lastReceivedPacket.newRows, sortCols) :
-               new SortedTable(lastReceivedPacket.newRows, comparer)
-         };
-         lastFiredPacket.addedRows = new OrderedBlueTable(lastFiredPacket.newRows);
-         lastFiredPacket.deletedRows = new BlueTable(lastFiredPacket.newRows.schema);
-         myFireEvent(lastFiredPacket.Clone());
-         return;
-      }
-      // Deletes
-      lastFiredPacket.deletedRows =
-         comparer == null ?
-         new SortedTable(lastReceivedPacket.deletedRows, sortCols) :
-         new SortedTable(lastReceivedPacket.deletedRows, comparer);
-      ((SortedTable)lastFiredPacket.newRows).deleteRows(lastFiredPacket.deletedRows);
-      // Adds
-      lastFiredPacket.addedRows = new BlueTable(lastReceivedPacket.addedRows);
-      ((SortedTable)lastFiredPacket.newRows).addRows(lastFiredPacket.addedRows);
-      myFireEvent(lastFiredPacket.Clone());
-   }
-
-   protected override void myOnFirstSubscriber() =>
-      stream.onChange += myChangeHandler;
-
-   protected override void myOnLastSubscriber() {
-      lastFiredPacket = null;
-      lastReceivedPacket = null;
-      stream.onChange -= myChangeHandler;
-   }
-}
+using Bts.ColumnSortExpressions;
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+
+namespace BCG;
+
+/// <summary>
+/// Defines a Sort stream, with performance of O(n) for all the increments. It uses simple merge sort
+/// to merge the additions to the accumulates table
+/// </summary>
+public class SortStream : ViewStream {
+   ViewStream stream;
+   IList<ColumnSortExpression> sortCols;
+   IComparer? comparer;
+   DataPacket? lastFiredPacket;
+   DataPacket? lastReceivedPacket;
+
+   public SortStream(ViewStream stream, string sortExpression) {
+      this.stream = stream;
+      SortExpression = sortExpression;
+   }
+
+   public SortStream(ViewStream vs, string colName, bool isAsc) {
+      stream = vs;
+      SortExpression = isAsc ? "+" + colName : "-" + colName;
+   }
+
+   public SortStream(ViewStream stream, IComparer comparer) {
+      this.stream = stream;
+      this.comparer = comparer;
+      sortCols = Array.Empty<ColumnSortExpression>();
+   }
+
+   [MemberNotNull(nameof(sortCols))]
+   public string SortExpression {
+      set {
+         comparer = null;
+         lastFiredPacket = null;
+         sortCols = ColumnSortExpressionInterpreter.Evaluate(value);
+         if (lastReceivedPacket is not null) {
+            myChangeHandler(lastReceivedPacket);
+         }
+      }
+   }
+
+   public IComparer Comparer {
+      set {
+         comparer = value;
+         lastFiredPacket = null;
+         if (lastReceivedPacket is not null) {
+            myChangeHandler(lastReceivedPacket);
+         }
+      }
+   }
+
+   public void myChangeHandlerTest(object o) =>
+      myChangeHandler(o);
+
+   [MemberNotNull(nameof(lastFiredPacket))]
+   internal void myChangeHandler(object o) {
+      lastReceivedPacket = (DataPacket)o;
+      // First callback, so we need to sort the whole table, this is the
+      // only time we will do that for all the other sorting operations would
+      // be sorting the increments and inserting them into the whole list
+      if (lastFiredPacket is null) {
+         lastFiredPacket = new() {
+            newRows = comparer is null ?
+               new SortedTable(lastReceivedPacket.newRows, sortCols) :
+               new SortedTable(lastReceivedPacket.newRows, comparer)
+         };
+         lastFiredPacket.addedRows = new OrderedBlueTable(lastFiredPacket.newRows);
+         lastFiredPacket.deletedRows = new BlueTable(lastFiredPacket.newRows.schema);
+         myFireEvent(lastFiredPacket.Clone());
+         return;
+      }
+      // Deletes
+      lastFiredPacket.deletedRows =
+         comparer == null ?
+         new SortedTable(lastReceivedPacket.deletedRows, sortCols) :
+         new SortedTable(lastReceivedPacket.deletedRows, comparer);
+      ((SortedTable)lastFiredPacket.newRows).deleteRows(lastFiredPacket.deletedRows);
+      // Adds
+      lastFiredPacket.addedRows = new BlueTable(lastReceivedPacket.addedRows);
+      ((SortedTable)lastFiredPacket.newRows).addRows(lastFiredPacket.addedRows);
+      myFireEvent(lastFiredPacket.Clone());
+   }
+
+   protected override void myOnFirstSubscriber() =>
+      stream.onChange += myChangeHandler;
+
+   protected override void myOnLastSubscriber() {
+      lastFiredPacket = null;
+      lastReceivedPacket = null;
+      stream.onChange -= myChangeHandler;
+   }
+}
@@ -1,49 +1,43 @@
-// using System;
+using System;

-// namespace BCG
-// {
-//    public class TopStream : MethodDrivenStream
-//    {
-//       private int myTopCount;
+namespace BCG {
+    public class TopStream : MethodDrivenStream {
+        private int myTopCount;

-//       public TopStream (ViewStream stream, int topCount) : base (stream)  {myTopCount = topCount;}
+        public TopStream(ViewStream stream, int topCount) : base(stream) { myTopCount = topCount; }

-//       public TopStream (ViewStream stream, 
-//          int topCount, 
-//          string sortExpression) 
-//          :
-//          this (sortExpression == null? 
-//          stream :
-//          new SortStream (stream, sortExpression), topCount)
-//       {}
+        public TopStream(ViewStream stream,
+           int topCount,
+           string sortExpression)
+           :
+           this(sortExpression == null ?
+           stream :
+           new SortStream(stream, sortExpression), topCount) { }

-//       protected override void myOnTableClear () 
-//       {
-//          myLastFiredPacket.deletedRows = myLastFiredPacket.newRows;
-//          myLastFiredPacket.newRows = new OrderedBlueTable (myLastFiredPacket.deletedRows.schema);
-//          myLastFiredPacket.addedRows = new OrderedBlueTable (myLastFiredPacket.deletedRows.schema);
-//       }
+        protected override void myOnTableClear() {
+            myLastFiredPacket.deletedRows = myLastFiredPacket.newRows;
+            myLastFiredPacket.newRows = new OrderedBlueTable(myLastFiredPacket.deletedRows.schema);
+            myLastFiredPacket.addedRows = new OrderedBlueTable(myLastFiredPacket.deletedRows.schema);
+        }

-//       protected override void myHandleFirstCall () 
-//       {
-//          myLastFiredPacket = new DataPacket ();
-//          myLastFiredPacket.newRows = new OrderedBlueTable (myLastArrivedPacket.newRows, myTopCount);
-//          myLastFiredPacket.addedRows = new OrderedBlueTable(myLastFiredPacket.newRows);
-//          myLastFiredPacket.deletedRows = new OrderedBlueTable (myLastFiredPacket.newRows.schema);
-//       }
+        protected override void myHandleFirstCall() {
+            myLastFiredPacket = new DataPacket();
+            myLastFiredPacket.newRows = new OrderedBlueTable(myLastArrivedPacket.newRows, myTopCount);
+            myLastFiredPacket.addedRows = new OrderedBlueTable(myLastFiredPacket.newRows);
+            myLastFiredPacket.deletedRows = new OrderedBlueTable(myLastFiredPacket.newRows.schema);
+        }

-//       protected override void myHandleIncrementalAdd ()     {}
+        protected override void myHandleIncrementalAdd() { }

-//       protected override void myHandleIncrementalDelete()   
-//       {
-//          IBlueRowCollection oldRows = myLastFiredPacket.newRows;
-//          myLastFiredPacket.newRows = new OrderedBlueTable (myLastArrivedPacket.newRows, myTopCount);
-//          BlueDataUtility.computeDifferences (myLastFiredPacket.newRows,
-//             oldRows,
-//             myLastFiredPacket.schema.columnNames,
-//             out myLastFiredPacket.deletedRows,
-//             out myLastFiredPacket.addedRows);
-//          myFireSwitch = myLastFiredPacket.addedRows.Count + myLastFiredPacket.deletedRows.Count == 0 ? false : true;
-//       }
-//    }
-// }
+        protected override void myHandleIncrementalDelete() {
+            IBlueRowCollection oldRows = myLastFiredPacket.newRows;
+            myLastFiredPacket.newRows = new OrderedBlueTable(myLastArrivedPacket.newRows, myTopCount);
+            BlueDataUtility.computeDifferences(myLastFiredPacket.newRows,
+               oldRows,
+               myLastFiredPacket.schema.columnNames,
+               out myLastFiredPacket.deletedRows,
+               out myLastFiredPacket.addedRows);
+            myFireSwitch = myLastFiredPacket.addedRows.Count + myLastFiredPacket.deletedRows.Count == 0 ? false : true;
+        }
+    }
+}
@@ -6,6 +6,7 @@ using System.Reflection;
 using System.IO;
 using System.Diagnostics;
 using System.Linq;
+using System.Globalization;

 //using BCG.Utilities;
 using BCG.Utilities.General;
@@ -292,21 +293,118 @@ namespace BCG {
         return TypeCode.Empty;
      }

-      public static IBlueTableSchema to_typed_schema(IBlueRowCollection rows) {
-         List<ColumnInfo> cis = new List<ColumnInfo>();
-         foreach (var col in rows.schema.columnInfo) {
-            var text_vals = BlueDataUtility.get_colvalues<string>(rows, col.colName);
-            TypeCode type_code = convert_column_type(text_vals);
-            cis.Add(new ColumnInfo(col.colName, cis.Count, _typecode_to_type[type_code]));
+      // public static Type guess_type(string val) {
+      //    //DateTime
+      //    {
+      //       DateTime dt;
+      //       var success = DateTime.TryParseExact(val, "yyyy-MM-dd HH:mm:ss", null, DateTimeStyles.AllowWhiteSpaces, out dt);
+      //       if (success) {
+      //          return typeof(DateTime);
+      //       }
+      //       DateTimeOffset dtoff;
+      //       success = DateTimeOffset.TryParseExact(val, "yyyy-MM-dd HH:mm:sszzz",
+      //                                              null, System.Globalization.DateTimeStyles.None, out dtoff);
+
+      //       if (success) {
+      //          return typeof(DateTime);
+      //       }
+      //    }
+      //    //int
+      //    {
+      //       int i;
+      //       var success = Int32.TryParse(val, out i);
+      //       if (success) {
+      //          return typeof(Int32);
+      //       }
+      //    }
+      //    //double
+      //    {
+      //       double d;
+      //       var success = Double.TryParse(val, out d);
+      //       if (success) {
+      //          return typeof(Double);
+      //       }
+      //    }
+      //    //bool
+      //    {
+      //       bool b;
+      //       var success = Boolean.TryParse(val, out b);
+      //       if (success) {
+      //          return typeof(bool);
+      //       }
+      //    }
+      //    //string
+      //    return typeof(string);
+      // }
+
+      private static Type[] _parsable_types = { typeof(DateTime), typeof(int), typeof(double), typeof(bool) };
+      public static Type guess_type(string val) {
+         foreach (var t in _parsable_types) {
+            var type_val = convert_to_type(t, val);
+            if (type_val != null)
+               return t;
         }
-         return new BlueTableSchema(cis.ToArray(), rows.schema.tableName);
+         return typeof(string);
+
      }

-      // public static IBlueRow convert_string_row(IBlueRow r, IBlueTableSchema out_schema) {
-      //    foreach (var ci in out_schema.columnInfo){
+      public static IBlueTableSchema get_typed_schema(IBlueRowCollection rows) {
+         // just use one row to guess
+         List<ColumnInfo> cis = new List<ColumnInfo>();
+         foreach (IBlueRow r in rows) {
+            foreach (var ci in r.schema.columnInfo) {
+               if (ci.colType != typeof(System.String)) {
+                  cis.Add(ci);
+                  continue;
+               }
+               Type type = guess_type(r[ci.colName] as string);
+               cis.Add(new ColumnInfo(ci.colName, ci.colNo, type));
+            }
+            return new BlueTableSchema(cis.ToArray(), rows.schema.tableName);
+         }
+         return null;
+      }
+
+      static object convert_to_type(Type t, string value) {
+         // Attempt to convert the string to the specified type
+         try {
+            return Convert.ChangeType(value, t);
+         } catch (Exception) {
+            if (t == typeof(double)) {
+               // some doubles come with currency and ',' we clean that up here (there might be better ways to do this)
+               string cleaned_val = new string(value.Where(c => c != '$' && c != ',').ToArray());
+               cleaned_val = cleaned_val.Replace('−', '-');
+               double rv_d;
+               if (Double.TryParse(cleaned_val, out rv_d))
+                  return rv_d;
+               else
+                  return null;
+            }
+            return null;
+            // Handle conversion failure gracefully
+            // throw new ArgumentException("Failed to convert the string to the specified type.");
+         }
+      }
+
+      // converts a row where all columns are string types to a schema where the best types are guesed
+      public static IBlueRowCollection get_typed_table(IBlueRowCollection string_rows) {
+         Func<IBlueRow, IBlueTableSchema, IBlueRow> get_typed_row = (IBlueRow string_row, IBlueTableSchema typed_schema) => {
+            MutableBlueRow rv = new MutableBlueRow(typed_schema);
+            foreach (ColumnInfo ci in typed_schema.columnInfo) {
+               var typed_val = convert_to_type(ci.colType, value: string_row[ci.colName].ToString());
+               rv.setValue(ci.colName, typed_val);
+            }
+            return rv;
+         };
+         IBlueTableSchema typed_schema = get_typed_schema(string_rows);
+         var rv = new BlueTable(typed_schema);
+         foreach (IBlueRow r in string_rows) {
+            var typed_row = get_typed_row(r, typed_schema);
+            rv.addRow(typed_row);
+         }
+         return rv;
+      }

-      //    }
-      // }


      /// <summary>
@@ -2112,5 +2210,33 @@ namespace BCG {
      }

      #endregion
+
+      public class RowComparer<T> : IComparer<IBlueRow> {
+         private readonly IEnumerable<Tuple<string, bool>> _sort_cols;
+         public RowComparer(IEnumerable<Tuple<string, bool>> sort_cols) {
+            _sort_cols = sort_cols;
+         }
+         public int Compare(IBlueRow? x, IBlueRow? y) {
+            Func<object, object, int> compare_cols = (o1, o2) => {
+               return (o1 as IComparable).CompareTo(o2);
+            };
+            foreach (var c in _sort_cols) {
+               int i = compare_cols(x[c.Item1], y[c.Item1]);
+
+            }
+            return 1;
+         }
+
+      }
+      public static IList<IBlueRow> get_sorted_row(IBlueRowCollection rows, IEnumerable<Tuple<string, bool>> sort_cols) {
+         List<IBlueRow> row_list = new List<IBlueRow>();
+         foreach (IBlueRow r in rows) {
+            row_list.Add(r);
+         }
+         var row_comparer = new RowComparer<IBlueRow>(sort_cols);
+         ParallelSort.QuicksortSequential<IBlueRow>(row_list, row_comparer);
+         return row_list;
+
+      }
   }
 }
@@ -0,0 +1,24 @@
+namespace Bts.DataStreamCore;
+
+using BCG;
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+
+public class BlueRowEqualityComparer : IEqualityComparer<IBlueRow> {
+   public static BlueRowEqualityComparer Instance { get; } = new();
+
+   public bool Equals(IBlueRow x, IBlueRow y) =>
+      x.schema.columnInfo.SequenceEqual(y.schema.columnInfo) &&
+      x.Values.Cast<object>().SequenceEqual(y.Values.Cast<object>());
+
+   public int GetHashCode([DisallowNull] IBlueRow obj) {
+      var hash = new HashCode();
+      foreach (var v in obj.Values) {
+         hash.Add(v?.GetHashCode() ?? 0);
+      }
+      return hash.ToHashCode();
+   }
+}
@@ -1,8 +1,15 @@
+using Bts.DataStreamCore;
+
+using Spark.DataStream;
+
 using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.Data;
+using System.Diagnostics.CodeAnalysis;
+
 //using BCG.Utilities;
+
 using System.Linq;

 namespace BCG {
@@ -10,7 +17,7 @@ namespace BCG {
   /// Anologue of the dotNet DataTable.
   /// </summary>
   [Serializable]
-   public class BlueTable : IBlueRowCollection {
+   public class BlueTable : IBlueRowCollection, IDictionary<int, IBlueRow> {
      /// <summary>
      /// Hashtable indexed on "id" to speed up removes
      /// </summary>
@@ -86,6 +93,12 @@ namespace BCG {
               throw new BlueDataException("ID " + id.ToString() + " does not exist in table " + mySchema.tableName);
            return (IBlueRow)row;
         }
+         set {
+            if ((int)value["id"] != id) {
+               throw new ArgumentException("id arg not equal to row's actual id", nameof(id));
+            }
+            changeRow(value);
+         }
      }

      /// <summary>
@@ -202,6 +215,8 @@ namespace BCG {

      #endregion

+      public IDictionary<int, IBlueRow> AsDictionary() => this;
+
      #region ICollection members
      public virtual IEnumerator GetEnumerator() //{return myRows.GetEnumerator ();}
      { return myIdIndex.Values.GetEnumerator(); }
@@ -214,5 +229,55 @@ namespace BCG {

      public virtual int Count { get { return myIdIndex.Count; } }
      #endregion
+
+      #region IDictionary<int, IBlueRow> members
+      public void Add(int key, IBlueRow value) {
+         throw new NotImplementedException();
+      }
+
+      bool IDictionary<int, IBlueRow>.ContainsKey(int key) =>
+         containsID(key);
+
+      bool IDictionary<int, IBlueRow>.Remove(int key) =>
+         deleteRow(key);
+
+      bool IDictionary<int, IBlueRow>.TryGetValue(
+         int key, [MaybeNullWhen(false)] out IBlueRow value) =>
+         tryGetValue(key, out value);
+
+      void ICollection<KeyValuePair<int, IBlueRow>>.Add(KeyValuePair<int, IBlueRow> item) =>
+         addRow(item.Value);
+
+      void ICollection<KeyValuePair<int, IBlueRow>>.Clear() =>
+         clear();
+
+      bool ICollection<KeyValuePair<int, IBlueRow>>.Contains(KeyValuePair<int, IBlueRow> item) =>
+         tryGetValue(item.Key, out var r)
+         && BlueRowEqualityComparer.Instance.Equals(r, item.Value);
+
+      void ICollection<KeyValuePair<int, IBlueRow>>.CopyTo(
+         KeyValuePair<int, IBlueRow>[] array, int arrayIndex) {
+         foreach (DictionaryEntry de in myIdIndex) {
+            array[arrayIndex++] = new((int)de.Key, (IBlueRow)de.Value);
+         }
+      }
+
+      bool ICollection<KeyValuePair<int, IBlueRow>>.Remove(KeyValuePair<int, IBlueRow> item) =>
+         deleteRow(item.Key);
+
+      IEnumerator<KeyValuePair<int, IBlueRow>> IEnumerable<KeyValuePair<int, IBlueRow>>.GetEnumerator() {
+         foreach (DictionaryEntry de in myIdIndex) {
+            yield return new((int)de.Key, (IBlueRow)de.Value);
+         }
+      }
+
+      ICollection<int> IDictionary<int, IBlueRow>.Keys =>
+         GenericCollectionWrapper.Create<int>(myIdIndex.Keys);
+
+      ICollection<IBlueRow> IDictionary<int, IBlueRow>.Values =>
+         GenericCollectionWrapper.Create<IBlueRow>(myIdIndex.Values);
+
+      bool ICollection<KeyValuePair<int, IBlueRow>>.IsReadOnly => false;
+      #endregion
   }
 }
@@ -0,0 +1,80 @@
+namespace Bts.DataStreamCore;
+
+using BCG;
+
+using System;
+using System.Collections;
+using System.Collections.Immutable;
+
+// I would have named this ImmutableBlueTable, but that was already taken.
+public class BlueTableImmutable : IBlueRowCollection, IImmutableRowCollection {
+   readonly ImmutableDictionary<int, IBlueRow> rows;
+
+   public BlueTableImmutable(IBlueTableSchema schema)
+      : this(schema, ImmutableDictionary<int, IBlueRow>.Empty) { }
+
+   public BlueTableImmutable(IBlueTableSchema schema, ImmutableDictionary<int, IBlueRow> rows) {
+      this.schema = schema;
+      this.rows = rows;
+   }
+
+   public int Count => rows.Count;
+   public bool IsSynchronized => false;
+   public IBlueTableSchema schema { get; }
+   public object SyncRoot => this;
+
+   public IBlueRow this[int id] => rows[id];
+
+   public bool containsID(int id) =>
+      rows.ContainsKey(id);
+
+   public void CopyTo(Array array, int index) {
+      foreach (var r in rows.Values) {
+         array.SetValue(r, index++);
+      }
+   }
+
+   public IEnumerator GetEnumerator() =>
+      rows.Values.GetEnumerator();
+
+   public DataPacketBuilder ToDataPacketBuilder() =>
+      new(this);
+
+   public class DataPacketBuilder {
+      readonly IBlueTableSchema schema;
+      readonly ImmutableDictionary<int, IBlueRow>.Builder table;
+      readonly ImmutableDictionary<int, IBlueRow>.Builder added =
+         ImmutableDictionary<int, IBlueRow>.Empty.ToBuilder();
+      readonly ImmutableDictionary<int, IBlueRow>.Builder removed =
+         ImmutableDictionary<int, IBlueRow>.Empty.ToBuilder();
+
+      public DataPacketBuilder(BlueTableImmutable table) {
+         schema = table.schema;
+         this.table = table.rows.ToBuilder();
+      }
+
+      public void AddOrUpdate(IBlueRow row) {
+         var id = row.Id();
+         added[id] = row;
+         if (table.TryGetValue(id, out var orig)) {
+            removed.Remove(id);
+         }
+      }
+
+      public void Remove(int id) {
+         added.Remove(id);
+         if (table.TryGetValue(id, out var orig)) {
+            removed[id] = orig;
+         }
+      }
+
+      public DataPacket ToDataPacket() {
+         table.RemoveRange(removed.Keys);
+         table.AddRange(added);
+         var newRows = new BlueTableImmutable(schema, table.ToImmutable());
+         var addedRows = new BlueTableImmutable(schema, added.ToImmutable());
+         var removedRows = new BlueTableImmutable(schema, removed.ToImmutable());
+         return new(newRows, addedRows, removedRows);
+      }
+   }
+}
@@ -0,0 +1,84 @@
+#nullable enable
+namespace Bts.DataStream;
+
+using BCG;
+
+using bts.collections;
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+public class BlueTableSchemaAdaptor<T> {
+   readonly string name;
+   readonly List<ColumnAdaptor> columns = [];
+   BlueTableSchema? schema;
+
+   public BlueTableSchemaAdaptor(string name) =>
+      this.name = name;
+
+   public IBlueTableSchema Schema =>
+      schema ??= new BlueTableSchema([.. columns.WrapSelectorRO(c => c.Info)], name);
+
+   public bool Contains(string name) =>
+      columns.Any(c => c.Info.colName == name);
+
+   public void AddColumn(string name, Func<T, int> getValue) =>
+      AddColumn(name, r => getValue(r), typeof(int));
+
+   public void AddColumn(string name, Func<T, int?> getValue) =>
+      AddColumn(name, r => getValue(r) ?? (object)DBNull.Value, typeof(int));
+
+   public void AddColumn(string name, Func<T, long> getValue) =>
+      AddColumn(name, r => getValue(r), typeof(long));
+
+   public void AddColumn(string name, Func<T, long?> getValue) =>
+      AddColumn(name, r => getValue(r) ?? (object)DBNull.Value, typeof(long));
+
+   public void AddColumn(string name, Func<T, double> getValue) =>
+      AddColumn(name, r => getValue(r), typeof(double));
+
+   public void AddColumn(string name, Func<T, double?> getValue) =>
+      AddColumn(name, r => getValue(r) ?? (object)DBNull.Value, typeof(double));
+
+   public void AddColumn(string name, Func<T, DateTime> getValue) =>
+      AddColumn(name, r => getValue(r), typeof(DateTime));
+
+   public void AddColumn(string name, Func<T, DateTime?> getValue) =>
+      AddColumn(name, r => getValue(r) ?? (object)DBNull.Value, typeof(DateTime));
+
+   public void AddColumn(string name, Func<T, string?> getValue) =>
+      AddColumn(name, r => getValue(r) ?? (object)DBNull.Value, typeof(string));
+
+   public void AddColumn(string name, Func<T, object?> getValue, Type dataType) {
+      if (!ColumnInfo.isAllowedType(dataType)) {
+         throw new ArgumentException(
+            $"'{dataType}' is not a supported column type", nameof(dataType));
+      }
+      // Invalidate cached schema (set it to null)
+      schema = null;
+      columns.Add(new ColumnAdaptor(new(name, columns.Count, dataType), r => getValue(r)));
+   }
+
+   public IBlueRow GetBlueRow(T item) {
+      var mbr = new MutableBlueRow(Schema);
+      foreach (var col in columns) {
+         mbr.setValue(col.Info.colNo, col.GetValue(item));
+      }
+      return mbr;
+   }
+
+   class ColumnAdaptor {
+      readonly Func<T, object?> getValue;
+
+      public ColumnAdaptor(ColumnInfo info, Func<T, object?> getValue) {
+         Info = info;
+         this.getValue = getValue;
+      }
+
+      public ColumnInfo Info { get; }
+
+      public object? GetValue(T row) =>
+         getValue(row);
+   }
+}
@@ -1,95 +1,103 @@
-using System;
-
-namespace BCG
-{
-   /// <summary>
-   /// Resprsents information about a column schema, ie its ordinal, the type, the name and constant value or expression. where applicable
-   /// </summary>
-   [Serializable]
-   public class ColumnInfo : IComparable
-   {
-      public static bool isAllowedType (Type t)
-      {
-         return 
-            t.Equals (typeof (System.Int32)) ||
-            t.Equals (typeof (System.Int64)) ||
-            t.Equals (typeof (System.Double)) ||
-            t.Equals (typeof (System.String)) ||
-            t.Equals (typeof (System.DateTime)) ? true :
-            false;
-      }
-
-      //the default column info does not cach values in a lookup table, therefore it is in group 0
-      public ColumnInfo(string colName, int colNo, Type colType)
-         : this(colName, colNo, colType, 0)
-      {
-
-
-      }
-
-      public ColumnInfo(string colName, int colNo, Type colType, short colGroup)
-      {
-         myColName = colName;
-         myColNo = colNo;
-         myColType = colType;
-         myLookupTableGroup = colGroup;
-         myColValue = null;
-      }
-
-
-      public ColumnInfo (string colName, int colNo, object colValue)
-         : this (colName, colNo, colValue.GetType())  {myColValue = colValue == null ? DBNull.Value : colValue;}
-
-      public ColumnInfo (string colName, int colNo, Type colType, object colValue)
-         : this (colName, colNo, colType) 
-      {
-
-         myColValue = colValue == null ? DBNull.Value : colValue;
-      
-      }
-
-
-      public int CompareTo (object obj)
-      {
-         int otherColNo = ((ColumnInfo)(obj)).colNo;
-         if (myColNo < otherColNo)
-            return -1;
-         else if (myColNo > otherColNo)
-            return 1;
-         return 0;
-      }
-
-      //public bool isCalculated{get{return myExpression != null;}}
-
-      public bool isConstant {get{return myColValue != null;}}
-
-      private int myColNo;
-      private string myColName;
-      private Type myColType;
-      //private string myExpression;
-      private object myColValue;
-
-      //no table will ever have more than 65,536 columns
-      //if it does, we are in serious trouble
-      private short myLookupTableGroup;
-
-      public int colNo{get{return myColNo;}}
-      public string colName {get{return myColName;}}
-      public Type colType {get{return myColType;}}
-
-
-      //this value corresponds to how the data in the column is serialized. 
-      //if the group number is 0, the values are not stored in a table
-      //if the vlaue is non-zero, all columns with the the same lookup table group are stored in the same lookup table together
-      //are stored together in a lookup table
-
-      
-      public short lookupTableGroup
-      {
-         get { return myLookupTableGroup; }
-         set { myLookupTableGroup = value; }
-      }
-      //public string expression {get{return myExpression;}}
-      public object colValue {get{return myColValue;}}
-   }
-}
+using System;
+using System.Text.Json.Serialization;
+
+namespace BCG
+{
+   /// <summary>
+   /// Resprsents information about a column schema, ie its ordinal, the type, the name and constant value or expression. where applicable
+   /// </summary>
+   [Serializable]
+   public class ColumnInfo : IComparable
+   {
+      public static bool isAllowedType (Type t)
+      {
+         return 
+            t.Equals (typeof (System.Int32)) ||
+            t.Equals (typeof (System.Int64)) ||
+            t.Equals (typeof (System.Double)) ||
+            t.Equals (typeof (System.String)) ||
+            t.Equals (typeof (System.DateTime)) ? true :
+            false;
+      }
+
+      //the default column info does not cach values in a lookup table, therefore it is in group 0
+      public ColumnInfo(string colName, int colNo, Type colType)
+         : this(colName, colNo, colType, 0)
+      {
+
+
+      }
+
+      public ColumnInfo(string colName, int colNo, Type colType, short colGroup)
+      {
+         myColName = colName;
+         myColNo = colNo;
+         myColType = colType;
+         myLookupTableGroup = colGroup;
+         myColValue = null;
+      }
+
+
+      public ColumnInfo (string colName, int colNo, object colValue)
+         : this (colName, colNo, colValue.GetType())  {myColValue = colValue == null ? DBNull.Value : colValue;}
+
+      public ColumnInfo (string colName, int colNo, Type colType, object colValue)
+         : this (colName, colNo, colType) 
+      {
+
+         myColValue = colValue == null ? DBNull.Value : colValue;
+      
+      }
+
+
+      public int CompareTo (object obj)
+      {
+         int otherColNo = ((ColumnInfo)(obj)).colNo;
+         if (myColNo < otherColNo)
+            return -1;
+         else if (myColNo > otherColNo)
+            return 1;
+         return 0;
+      }
+
+      //public bool isCalculated{get{return myExpression != null;}}
+
+      public bool isConstant {get{return myColValue != null;}}
+
+      private int myColNo;
+      private string myColName;
+      private Type myColType;
+      //private string myExpression;
+      private object myColValue;
+
+      //no table will ever have more than 65,536 columns
+      //if it does, we are in serious trouble
+      private short myLookupTableGroup;
+
+      [JsonPropertyName("colNo")]
+      public int colNo{get{return myColNo;}}
+
+      [JsonPropertyName("colName")]
+      public string colName {get{return myColName;}}
+
+      [JsonPropertyName("colType")]
+      public Type colType {get{return myColType;}}
+
+
+      //this value corresponds to how the data in the column is serialized. 
+      //if the group number is 0, the values are not stored in a table
+      //if the vlaue is non-zero, all columns with the the same lookup table group are stored in the same lookup table together
+      //are stored together in a lookup table
+
+      
+      [JsonIgnore]
+      public short lookupTableGroup
+      {
+         get { return myLookupTableGroup; }
+         set { myLookupTableGroup = value; }
+      }
+      //public string expression {get{return myExpression;}}
+      [JsonIgnore]
+      public object colValue {get{return myColValue;}}
+   }
+}
@@ -0,0 +1,11 @@
+namespace Bts.DataStreamCore;
+
+using BCG;
+
+using System;
+
+public static class BlueRowExtensions {
+   public static int Id(this IBlueRow row) =>
+      (int)(row["id"] ?? throw new ArgumentException(
+         "Row doesn't have an 'id' column", nameof(row)));
+}
@@ -0,0 +1,61 @@
+#nullable enable
+using BCG;
+
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Bts.DataStreamCore;
+
+class BlueRowJsonConverter : JsonConverter<IBlueRow> {
+   IBlueTableSchema? schema = null;
+
+   public override IBlueRow Read(
+      ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+      if (schema is null) {
+         throw new InvalidOperationException("Cannot read row from json because schema is null");
+      }
+      var mbr = new MutableBlueRow(schema);
+      int colNum = 0;
+      switch (reader.TokenType) {
+         case JsonTokenType.StartArray:
+            while (reader.Read() && reader.TokenType != JsonTokenType.EndArray) {
+               mbr.setValue(colNum++, readCellValue(ref reader));
+               colNum++;
+            }
+            break;
+         case JsonTokenType.StartObject:
+            while (reader.Read() && reader.TokenType != JsonTokenType.EndObject) {
+               if (reader.TokenType != JsonTokenType.PropertyName) {
+                  throw new InvalidOperationException(
+                     "Expected 'PropertyName' immediately after 'StartObject' token in row json");
+               }
+               var colName = reader.GetString();
+               if (!reader.Read()) {
+                  throw new InvalidOperationException(
+                     "Failed to read token immediately after 'PropertyName' token in row json");
+               }
+               mbr.setValue(colName, readCellValue(ref reader));
+            }
+            break;
+      }
+      if (mbr.Count != schema.columnInfo.Length) {
+         throw new InvalidOperationException(
+            $"Row json array length '{mbr.Count}' does not match the schema's " +
+            $"column length '{schema.columnInfo.Length}'.");
+      }
+      return mbr;
+
+      static object? readCellValue(ref Utf8JsonReader reader) =>
+         reader.TokenType switch {
+            JsonTokenType.String => reader.GetString(),
+            JsonTokenType.Number => reader.GetDouble(),
+            JsonTokenType.True or JsonTokenType.False => reader.GetBoolean(),
+            _ => throw new InvalidOperationException("Failed to read cell value"),
+         };
+   }
+
+   public override void Write(Utf8JsonWriter writer, IBlueRow value, JsonSerializerOptions options) {
+      throw new NotImplementedException();
+   }
+}
@@ -0,0 +1,155 @@
+#nullable enable
+using BCG;
+
+using Spark.Core.Json;
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace Bts.DataStreamCore;
+
+class DataPacketJsonConverter : JsonConverter<DataPacket> {
+   /// <summary>
+   /// Whether or not to include a field for current rows (i.e., snapshot of current state). By
+   /// default, only incremental changes are included ('added' and 'deleted').
+   /// </summary>
+   public bool IncludeCurrent { get; set; }
+
+   /// <summary>
+   /// Whether to treat rows as objects (name/value pairs), or arrays (list of values). Arrays
+   /// result in smaller payloads, but aren't as easy to read as name/value pairs (for mere humans).
+   /// </summary>
+   public bool UseObjectRows { get; set; }
+
+   public override DataPacket? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) {
+      if (!reader.ReadObject()) {
+         return null;
+      }
+      if (!reader.ReadPropertyName(out var prop)) {
+         return null;
+      }
+      if (!reader.Read()) {
+         return null;
+      }
+      if (prop == "added") {
+         var added = new List<MutableBlueRow>();
+         if (reader.TokenType != JsonTokenType.StartArray) {
+            return null;
+         }
+         while (true) {
+            if (!reader.Read()) {
+               break;
+            }
+            if (reader.TokenType != JsonTokenType.StartArray || !reader.Read()) {
+               return null;
+            }
+            switch (reader.TokenType) {
+               case JsonTokenType.String:
+                  // DAMNIT! Need the schema.
+                  break;
+            }
+         }
+      }
+      return null;
+   }
+
+   public override void Write(Utf8JsonWriter writer, DataPacket value, JsonSerializerOptions options) {
+      using var _ = writer.WriteObject();
+      using (writer.WriteArray("schema")) {
+         foreach (var col in value.schema.columnInfo) {
+            using (writer.WriteObject()) {
+               writer.WriteString("name", col.colName);
+               writer.WriteNumber("index", col.colNo);
+               // TODO: use language agnostic type names (e.g., 'string', 'integer', 'float', 'date' etc.)
+               writer.WriteString("type", col.colType.ToString());
+            }
+         }
+      }
+
+      var cellWriters = value.schema.columnInfo.Select(getCellWriter).ToList();
+      using (writer.WriteArray("added")) {
+         foreach (IBlueRow row in value.addedRows) {
+            using (writer.WriteArray()) {
+               for (int i = 0; i < cellWriters.Count; i++) {
+                  cellWriters[i](row[i]);
+               }
+            }
+         }
+      }
+      using (writer.WriteArray("deleted")) {
+         foreach (IBlueRow row in value.deletedRows) {
+            using (writer.WriteArray()) {
+               for (int i = 0; i < cellWriters.Count; i++) {
+                  cellWriters[i](row[i]);
+               }
+            }
+         }
+      }
+      if (IncludeCurrent) {
+         using (writer.WriteArray("current")) {
+            foreach (IBlueRow row in value.newRows) {
+               using (writer.WriteArray()) {
+                  for (int i = 0; i < cellWriters.Count; i++) {
+                     cellWriters[i](row[i]);
+                  }
+               }
+            }
+         }
+      }
+
+      Action<object?> getCellWriter(ColumnInfo colInfo) {
+         var writeVal = getCellValueWriter(colInfo);
+         if (!UseObjectRows) {
+            return writeVal;
+         }
+         return v => {
+            writer.WritePropertyName(colInfo.colName);
+            writeVal(v);
+         };
+      }
+
+      Action<object?> getCellValueWriter(ColumnInfo colInfo) {
+         var t = colInfo.colType;
+         if (t == typeof(int)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((int)v));
+         }
+         if (t == typeof(uint)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((uint)v));
+         }
+         if (t == typeof(long)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((long)v));
+         }
+         if (t == typeof(ulong)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((ulong)v));
+         }
+         if (t == typeof(short)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((short)v));
+         }
+         if (t == typeof(ushort)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((ushort)v));
+         }
+         if (t == typeof(double)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((double)v));
+         }
+         if (t == typeof(float)) {
+            return nullCheckWrapper(v => writer.WriteNumberValue((float)v));
+         }
+         if (t == typeof(bool)) {
+            return nullCheckWrapper(v => writer.WriteBooleanValue((bool)v));
+         }
+         return nullCheckWrapper(v => writer.WriteStringValue(v?.ToString()));
+
+         Action<object?> nullCheckWrapper(Action<object> writeNonNull) =>
+            v => {
+               if (v is null) {
+                  writer.WriteNullValue();
+               } else {
+                  writeNonNull(v);
+               }
+            };
+      }
+   }
+}
@@ -2,7 +2,7 @@

  <PropertyGroup>
    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <Nullable>disable</Nullable>
  </PropertyGroup>

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
@@ -0,0 +1,12 @@
+{
+  "user": "bts",
+  "prepublish_tables": {
+    "bbo": "bbo()",
+    "instruments": "instruments()",
+    "timesales": "timesales(10000)",
+    "books": "books()",
+    "seconds_1_10": "second(1,10)",
+    "literal_420": "literal(\"x\", \"420.0\")",
+    "mongodb_testcollection": "mongodb(\"mongodb+srv://johnc-dev:DMhDhP!g-TKeK.5@atlas-online-archive-5e18ab3c77c74d1cffa64c03-m7jkr.a.query.mongodb.net/?ssl=true&authSource=admin\",\"admin\",\"test_collection\")"
+  }
+}
@@ -0,0 +1,4 @@
+{
+  "user": "bts",
+  "simple_echo_client": true
+}
@@ -1,5 +1,16 @@
 <Project Sdk="Microsoft.NET.Sdk">

+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="CommandLineParser" Version="2.9.1" />
+  </ItemGroup>
+
  <ItemGroup>
    <ProjectReference Include="..\..\client\spark_api\spark_api.csproj" />
    <ProjectReference Include="..\..\client\spark_core\spark_core.csproj" />
@@ -9,11 +20,4 @@
    <ProjectReference Include="..\PubSub\PubSub.csproj" />
  </ItemGroup>

-  <PropertyGroup>
-    <OutputType>Exe</OutputType>
-    <TargetFramework>net7.0</TargetFramework>
-    <Nullable>enable</Nullable>
-    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-  </PropertyGroup>
-
 </Project>
@@ -0,0 +1,76 @@
+namespace Bts.DataStreamPublisher;
+
+using CommandLine;
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+public class DataStreamPublisherConfig {
+   /// <summary>
+   /// The login user for sparkd
+   /// </summary>
+   [JsonPropertyName("user")]
+   [Option("user", HelpText = "The sparkd login user")]
+   public string? User { get; set; }
+
+   /// <summary>
+   /// The login password for sparkd
+   /// </summary>
+   [JsonPropertyName("password")]
+   [Option("pass", HelpText = "The sparkd login password")]
+   public string? Password { get; set; }
+
+   /// <summary>
+   /// The config server url for sparkd
+   /// </summary>
+   [JsonPropertyName("sparkd")]
+   [Option("sparkd", HelpText = "The sparkd config server")]
+   public string? Sparkd { get; set; }
+
+   /// <summary>
+   /// The tables to publish on startup. Each key/value represents a table name/query to publish.
+   /// </summary>
+   [JsonPropertyName("prepublish_tables")]
+   public Dictionary<string, string>? PrepublishTables { get; set; }
+
+   [JsonPropertyName("simple_echo_client")]
+   [Option("simple-echo-client", HelpText = "Run a simple echo client (won't publish tables or connect to sparkd)")]
+   public bool? SimpleEchoClient { get; set; }
+
+   [Option(
+      "config",
+      MetaValue = "PATH",
+      HelpText = "Path to json file representing these options (DataStreamPublisherConfig)")]
+   [JsonIgnore]
+   public string? ConfigFile { get; set; }
+
+   public void MergeWith(DataStreamPublisherConfig other) {
+      User ??= other.User;
+      Password ??= other.Password;
+      Sparkd ??= other.Sparkd;
+      PrepublishTables ??= other.PrepublishTables;
+      SimpleEchoClient ??= other.SimpleEchoClient;
+      ConfigFile ??= other.ConfigFile;
+   }
+
+   /// <summary>
+   /// Merges options with those defined in `ConfigFile` (does not overwrite
+   /// non-null existing values).
+   /// </summary>
+   /// <exception cref="InvalidOperationException">
+   /// JsonSerializer.Deserialize returns null
+   /// </exception>
+   public void MergeWithConfigFile() {
+      if (ConfigFile is null) {
+         return;
+      }
+      var cfgString = File.ReadAllText(ConfigFile);
+      var parsedCfg = JsonSerializer.Deserialize<DataStreamPublisherConfig>(cfgString) ??
+         throw new InvalidOperationException($"Failed to parse json from {ConfigFile}");
+      MergeWith(parsedCfg);
+      ConfigFile = null;
+   }
+}
Author	SHA1	Message	Date
John Colvin	c80374579e	fix build: Add a few includes, suppress some werrors Not sure how this slipped through the cracks, but I'm guessing the build broke when we upgraded the cpp compilers (to clang 17 and gcc 13). * Include <cstdint> in a few places * Suppress -Wstringop-overflow in sparkd-gcc-release build * Change const char * param to explicit std::string for proper type deduction in call to 'std::make_tuple'. For some reason, the gcc build was failing with an array-bounds werror (changing the arg fixed it).	2024-03-18 19:14:48 +00:00
John Colvin	81cc0892f2	fix build: Remove version suffix from RuntimeIdentifiers in csprojs They aren't required (nor supported) in dotnet 8	2024-03-18 15:13:01 -04:00
John Colvin	88714bb4b5	cleanup: Remove unnused token in BooleanExpression lex	2024-03-18 15:09:49 -04:00
John Colvin	f39f1784a8	cleanup: Remove 'global.json' file This config file is an artifact leftover from dotnet 6. I'm pretty sure it's useless now.	2024-03-18 15:09:49 -04:00
John Colvin	b7c8e72a07	feat: Add [incremental] MongoCollectionStream	2024-03-18 15:09:27 -04:00
John Colvin	eea4af1f9b	refactor: Impl IDictionary<int, IBlueRow> in BlueTable	2024-03-13 13:43:35 -05:00
John Colvin	6a244fee35	Normalize indentation in MongoDBStream	2024-03-13 13:43:35 -05:00
John Colvin	d6a744e5ab	Add echoDelay param to SimpleTCPServer	2024-03-13 13:43:35 -05:00
John Colvin	6f86b41f02	Add IObservable ViewStream wrapper	2024-03-13 13:43:35 -05:00
John Colvin	faaa0ba8f1	refactor: Rename WebsocketServerConfig proto pkg 'bts.websocket_core' This matches the namespace used in spark_websocket csproj. Eventually, I'd like to use conventional capitalization (TitleCase namespaces/types, etc.), but let's shelf that until we have enough time/energy to do a more comprehensive refactoring.	2024-03-13 13:43:35 -05:00
John Colvin	be97879db0	Add json facilities for DataStream websocket api	2024-03-13 13:43:34 -05:00
John Colvin	b54d839aaf	refactor: Add handy WebsocketExtensions * IsSocketStateOpen * IsClosedProperly	2024-03-13 13:43:34 -05:00
John Colvin	3af79a239a	feat: Add Bts.DataStream.Websocket/Server	2024-03-13 13:43:34 -05:00
John Colvin	d6d5e1d292	Add bones for Bts.DataStreamWebApp.Client	2024-03-13 13:43:33 -05:00
John Colvin	e92e5d5039	Add bones for Bts.DataStreamWebApp.Server	2024-03-13 13:43:33 -05:00
John Colvin	c47226f965	feat: Add JsonRpc types for websocket paradigm	2024-03-13 13:43:33 -05:00
John Colvin	f19f2c7a81	cleanup: Remove empty file (clearly added by accident)	2024-03-13 13:43:33 -05:00
John Colvin	b92fac9e55	Add more descriptive logs (via stdout) during initialization The C++ configure/initialize routines were particularly opaque	2024-03-13 13:43:33 -05:00
John Colvin	a1fe672271	fix: Fix improper 'OfType' linq cast Previously, animations were expressed through polymorphism (derived from the base class CellAnimation), but the new impl uses composition. This 'OfType' call was leftover from the polymorphism implementation, an attempt to linq cast elements of base class (CellAnimation) to BackgroundAnimation.	2024-03-13 13:43:33 -05:00
John Colvin	99d01fd25d	cleanup: Remove static service Locator class It relied on a static singleton 'ServiceContext'. Replace references with a properly scoped (i.e., non-static) ServiceContext	2024-03-13 13:43:32 -05:00
John Colvin	ae1a420d5f	refactor: Reduce code (simplify) in BTS.init Remove the 'args' parameter, since the cmd line can be obtained from Environment.GetCommandLine anyways	2024-03-13 13:43:32 -05:00
John Colvin	a162640b5e	Dispose connections in SimpleTCPServer.Dispose	2024-03-13 13:43:32 -05:00
John Colvin	61db677c2a	improvement: Polish clis in DataStreamSuite Namely, PubSubServer and DataStreamPublisher * Use CommandLineParser (nuget pkg) * Clean up csproj files a bit while we're at it	2024-03-13 13:43:32 -05:00
John Colvin	c1ebb1f7c5	editorconfig: Use standard c# capitalization rules * Use 'PascalCase' for public members (instead of 'snake_case') * Use 'camelCase' for private members (instead of '_snake_case')	2024-03-13 13:43:32 -05:00
John Colvin	96cb88505d	refactor: Change WebsocketServerConfig.port to uint32 It should always be a number between 1-65535	2024-03-13 13:43:32 -05:00
John Colvin	ed31ea8c67	refactor: Add WebsocketClient class Basically an ISubject (I/O) wrapper for IWebsocketConnectionGateway	2024-03-13 13:43:31 -05:00
John Colvin	82e9939343	refactor: Remove nullability constraint in GetValueOrDefault	2024-03-13 13:43:31 -05:00
John Colvin	8021cb49cc	refactor: Use events to avoid circular deps for ws sync/gateway	2024-03-13 13:43:31 -05:00
John Colvin	a7eb58311d	refactor: Let caller specify nullability of T in json parse fn	2024-03-13 13:43:31 -05:00
John Colvin	45ea54bdde	refactor: Reorganize NumericComparer, support all types Get rid of redundant UniversalNumericComparer while we're at it	2024-03-13 13:43:31 -05:00
John Colvin	0266d09e20	docker: Update and clean up Dockerfile * Upgrade dotnet 7 -> 8 * Upgrade clang (13, 15) -> 17 * Upgrade gcc (11, 12) -> 13 * Remove kitware release candidate apt repo (probably shouldn't have been added in the first place). * Install gdb for c++ debugging (VS Code debugger depends on this) * Use explicit release ubuntu:22.04 (not 'latest'). We don't want the distro to automatically upgrade one day, when 'latest' suddenly points to a new release. Upgrades like that need to be done deliberately. * Use more granular RUN cmds to reduce rebuild times. When a Dockerfile is built, the RUN cmds are executed in the order in which they were written (duh!). Checkpoints called "cache layers" are saved for each RUN cmd, so if the Dockerfile is later modified, the image can be rebuilt from the most recent layer that wasn't invalidated by the modifications.	2024-03-13 13:43:31 -05:00
John Colvin	b6fa2bd1c2	cleanup: Remove leftover legacy files	2024-03-13 13:43:30 -05:00
John Colvin	d43fd5bce7	build: Upgrade c# to net8.0	2024-03-13 13:43:30 -05:00
John Colvin	60df5b2a68	refactor: Move OrderDataHelper to spark_api.csproj So it can be called from the websocket api server to parse CustomOrderDefinitions	2024-03-13 12:45:17 -05:00
Taha Afzal	bada5dc961	Fixing SimExecution for CME	2024-03-06 14:11:02 -05:00
Taha Afzal	4510e120ab	enabling some streams like max, that were dependent on AddCOlumns (thta John fixed in the last commit)	2024-02-12 13:21:28 -05:00
Taha Afzal	da2af06ee6	Merging	2024-02-08 15:48:51 -05:00
Taha Afzal	8c1342230b	RowDiff added	2024-02-08 14:11:10 -05:00
Taha Afzal	8dd2775092	Added volatility to trade bars	2024-02-04 23:22:52 -05:00
Taha Afzal	8966b73ac9	Merge branch 'development' of bitbucket.org:bluetradesys/spark into development	2024-02-04 18:04:06 -05:00
Taha Afzal	ddb2a91763	Adding TradBar stream	2024-02-04 18:03:51 -05:00
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