Add example of native client

.gitignore

@@ -113,4 +113,40 @@ dist
 .yarn/cache
 .yarn/unplugged
 .yarn/build-state.yml
-.pnp.*
+.pnp.*
+
+# dotnet
+*.swp
+*.*~
+project.lock.json
+.DS_Store
+*.pyc
+nupkg/
+
+# Visual Studio Code
+.vscode
+
+# Rider
+.idea
+
+# User-specific files
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+
+# Build results
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+build/
+bld/
+[Bb]in/
+[Oo]bj/
+[Oo]ut/
+msbuild.log
+msbuild.err
+msbuild.wrn

dotnet-client/Program.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using Newtonsoft.Json;
+using Websocket.Client;
+
+namespace dotnet_client
+{
+  static class Program
+  {
+    const string LoginEndpoint = "http://localhost:9000/login";
+    const string UserID = "1234";
+    static Uri WebSocketEndpoint = new Uri("ws://localhost:9001");
+
+    static async Task Main(string[] args)
+    {
+      HttpClient client = new HttpClient();
+
+      client.DefaultRequestHeaders.Add("user", UserID);
+      dynamic response = JsonConvert.DeserializeObject(await client.GetStringAsync(LoginEndpoint));
+      string sessionId = response.sessionId;
+      Console.WriteLine("Obtained session ID: " + sessionId);
+
+      using (var socket = new WebsocketClient(WebSocketEndpoint))
+      {
+        await socket.Start();
+
+        socket.MessageReceived.Subscribe(msg =>
+        {
+          dynamic payload = JsonConvert.DeserializeObject(msg.Text);
+          if (payload["event"] == "sessionInvalidated")
+          {
+            Console.WriteLine("You have logged in elsewhere. Exiting.");
+            Environment.Exit(0);
+          }
+        });
+
+        socket.Send(JsonConvert.SerializeObject(new
+        {
+          action = "subscribeToSessionInvalidation",
+          args = new
+          {
+            sessionId = sessionId
+          }
+        }));
+
+        Console.WriteLine("Press ENTER to exit.");
+        Console.ReadLine();
+      }
+    }
+  }
+}

dotnet-client/dotnet-client.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <RootNamespace>dotnet_client</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
+    <PackageReference Include="Websocket.Client" Version="4.3.12" />
+  </ItemGroup>
+
+</Project>