auto upgrade transport protocol

Author: doghappy

src/SocketIOClient.UnitTest/RouterTest.cs

@@ -0,0 +1,44 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using SocketIOClient.UriConverters;
+using SocketIOClient.Routers;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using SocketIOClient.Transport;
+using RichardSzalay.MockHttp;
+
+namespace SocketIOClient.UnitTest
+{
+    [TestClass]
+    public class RouterTest
+    {
+        [TestMethod]
+        public async Task V2_Server_Only_Support_Polling_ReturnsPolling()
+        {
+            string uri = "ws://localhost:11002/socket.io/?token=V2&EIO=3&transport=polling";
+            var mockHttp = new MockHttpMessageHandler();
+            mockHttp
+                .When(uri)
+                .Respond("application/json", "85:0{\"sid\":\"LvT3j_n54ltd7NtZAAAA\",\"upgrades\":[],\"pingInterval\":10000,\"pingTimeout\":5000}");
+            var httpClient = mockHttp.ToHttpClient();
+            TransportProtocol protocol = await Router.GetProtocolAsync(httpClient, new Uri(uri));
+            Assert.AreEqual(TransportProtocol.Polling, protocol);
+        }
+
+        [TestMethod]
+        public async Task V2_Server_Support_Polling_And_WebSocket_ReturnsWebSocket()
+        {
+            string uri = "ws://localhost:11002/socket.io/?token=V2&EIO=3&transport=polling";
+            var mockHttp = new MockHttpMessageHandler();
+            mockHttp
+                .When(uri)
+                .Respond("application/json", "85:0{\"sid\":\"LvT3j_n54ltd7NtZAAAA\",\"upgrades\":[\"websocket\"],\"pingInterval\":10000,\"pingTimeout\":5000}");
+            var httpClient = mockHttp.ToHttpClient();
+
+            TransportProtocol protocol = await Router.GetProtocolAsync(httpClient, new Uri(uri));
+            Assert.AreEqual(TransportProtocol.WebSocket, protocol);
+        }
+    }
+}

src/SocketIOClient/Routers/Router.cs

@@ -27,6 +27,7 @@ public Router(HttpClient httpClient, Func<IClientWebSocket> clientWebSocketProvi
         protected SocketIOOptions Options { get; }
 
         protected OpenedMessage OpenedMessage { get; set; }
+
         CancellationTokenSource _pingTokenSource;
         DateTime _pingTime;
 
@@ -254,5 +255,15 @@ public virtual void Dispose()
         {
             _messageQueue.Clear();
         }
+
+        public static async Task<TransportProtocol> GetProtocolAsync(HttpClient httpClient, Uri uri)
+        {
+            string text = await httpClient.GetStringAsync(uri);
+            if (text.Contains("websocket"))
+            {
+                return TransportProtocol.WebSocket;
+            }
+            return TransportProtocol.Polling;
+        }
     }
 }

src/SocketIOClient/SocketIO.cs

@@ -9,6 +9,7 @@
 using SocketIOClient.Messages;
 using SocketIOClient.Routers;
 using SocketIOClient.Transport;
+using SocketIOClient.UriConverters;
 
 namespace SocketIOClient
 {
@@ -162,10 +163,16 @@ private void Initialize()
             };
         }
 
-        private void CreateRouterIfNull()
+        private async Task CreateRouterAsync()
         {
             if (Router == null)
             {
+                if (Options.AutoUpgrade && Options.Transport == TransportProtocol.Polling)
+                {
+                    var uriConverter = new UriConverter();
+                    Uri uri = uriConverter.GetServerUri(false, ServerUri, Options.EIO, Options.Path, Options.Query);
+                    Options.Transport = await Routers.Router.GetProtocolAsync(HttpClient, uri);
+                }
                 if (Options.Transport == TransportProtocol.Polling)
                 {
                     Router = new HttpRouter(HttpClient, ClientWebSocketProvider, Options);
@@ -183,7 +190,7 @@ private void CreateRouterIfNull()
 
         public async Task ConnectAsync()
         {
-            CreateRouterIfNull();
+            await CreateRouterAsync();
             _reconnectionDelay = Options.ReconnectionDelay;
             while (true)
             {

src/SocketIOClient/SocketIOOptions.cs

@@ -15,8 +15,9 @@ public SocketIOOptions()
             Path = "/socket.io";
             ConnectionTimeout = TimeSpan.FromSeconds(20);
             Reconnection = true;
-            Transport = TransportProtocol.WebSocket;
+            Transport = TransportProtocol.Polling;
             EIO = 4;
+            AutoUpgrade = true;
         }
 
         public string Path { get; set; }
@@ -56,5 +57,7 @@ public double RandomizationFactor
         public TransportProtocol Transport { get; set; }
 
         public int EIO { get; set; }
+
+        public bool AutoUpgrade { get; set; }
     }
 }