Provide server current state (CacheReady, IndexOk etc.) during the handshake operation

Author: Gencebay Demir

src/NetCoreStack.WebSockets.ProxyClient/ServiceCollectionExtensions.cs

@@ -1,5 +1,6 @@
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Options;
+using NetCoreStack.WebSockets.Common;
 using System;
 using System.Linq;
 
@@ -9,6 +10,7 @@ public static class ServiceCollectionExtensions
     {
         public static void AddProxyWebSockets(this IServiceCollection services, Action<ConnectorOptions> setup)
         {
+            services.AddTransient<IHandshakeStateTransport, DefaultHandshakeStateTransport>();
             services.AddSingleton<IWebSocketConnector, ClientWebSocketConnector>();
             services.AddSingleton<InvocatorRegistry>();
             var connectorOptions = new ConnectorOptions { };

src/NetCoreStack.WebSockets/DefaultHandshakeStateTransport.cs

@@ -0,0 +1,12 @@
+using System.Threading.Tasks;
+
+namespace NetCoreStack.WebSockets.Common
+{
+    public class DefaultHandshakeStateTransport : IHandshakeStateTransport
+    {
+        public Task<object> GetStateAsync()
+        {
+            return Task.FromResult<object>(0);
+        }
+    }
+}

src/NetCoreStack.WebSockets/IHandshakeStateTransport.cs

@@ -0,0 +1,9 @@
+using System.Threading.Tasks;
+
+namespace NetCoreStack.WebSockets.Common
+{
+    public interface IHandshakeStateTransport
+    {
+        Task<object> GetStateAsync();
+    }
+}

src/NetCoreStack.WebSockets/Internal/ConnectionManagerExtensions.cs

@@ -1,19 +1,21 @@
-using System.Net.WebSockets;
+using NetCoreStack.WebSockets.Common;
+using System.Net.WebSockets;
 using System.Threading.Tasks;
 
 namespace NetCoreStack.WebSockets.Internal
 {
     internal static class ConnectionManagerExtensions
     {
-        public static async Task Handshake(this IConnectionManager manager, WebSocket webSocket)
+        public static async Task Handshake(this IConnectionManager manager, 
+            WebSocket webSocket, 
+            IHandshakeStateTransport initState)
         {
             WebSocketTransport transport = new WebSocketTransport(webSocket);
 
-            var context = new WebSocketMessageContext
-            {
-                Command = WebSocketCommands.Handshake,
-                Value = transport.ConnectionId
-            };
+            var context = new WebSocketMessageContext();
+            context.Command = WebSocketCommands.Handshake;
+            context.Value = transport.ConnectionId;
+            context.State = await initState.GetStateAsync();            
 
             await manager.SendAsync(transport.ConnectionId, context, webSocket);
             await transport.Echo();

src/NetCoreStack.WebSockets/Internal/WebSocketMiddleware.cs

@@ -1,16 +1,19 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Logging;
+using NetCoreStack.WebSockets.Common;
 using System.Threading.Tasks;
 
 namespace NetCoreStack.WebSockets.Internal
 {
     public class WebSocketMiddleware
     {
-        private readonly RequestDelegate next;
+        private readonly IHandshakeStateTransport _initState;
+        private readonly RequestDelegate _next;
 
-        public WebSocketMiddleware(RequestDelegate next)
+        public WebSocketMiddleware(RequestDelegate next, IHandshakeStateTransport initState)
         {
-            this.next = next;
+            _next = next;
+            _initState = initState;
         }
 
         public async Task Invoke(HttpContext httpContext, 
@@ -20,11 +23,11 @@ public async Task Invoke(HttpContext httpContext,
             if (httpContext.WebSockets.IsWebSocketRequest)
             {
                 var webSocket = await httpContext.WebSockets.AcceptWebSocketAsync();
-                await manager.Handshake(webSocket);
+                await manager.Handshake(webSocket, _initState);
             }
             else
             {
-                await next(httpContext);
+                await _next(httpContext);
             }
         }
     }

src/NetCoreStack.WebSockets/SocketServiceCollectionExtensions.cs

@@ -1,4 +1,5 @@
 using Microsoft.Extensions.DependencyInjection;
+using NetCoreStack.WebSockets.Common;
 using NetCoreStack.WebSockets.Internal;
 using System;
 
@@ -13,6 +14,7 @@ public static void AddNativeWebSockets(this IServiceCollection services)
                 throw new ArgumentNullException(nameof(services));
             }
 
+            services.AddTransient<IHandshakeStateTransport, DefaultHandshakeStateTransport>();
             services.AddSingleton<IConnectionManager, ConnectionManager>();
         }
     }

src/NetCoreStack.WebSockets/WebSocketExtensions.cs

@@ -1,8 +1,7 @@
-using System;
+using Newtonsoft.Json;
+using System;
 using System.Net.WebSockets;
 using System.Text;
-using Newtonsoft.Json;
-using System.Threading.Tasks;
 
 namespace NetCoreStack.WebSockets
 {

src/NetCoreStack.WebSockets/WebSocketMessageContext.cs

@@ -4,6 +4,7 @@ public class WebSocketMessageContext
     {
         public WebSocketCommands? Command { get; set; }
         public object Value { get; set; }
+        public object State { get; set; }
 
         public string CommandText
         {