Add basic websocket redirect support

src/Discord.Net/API/Models/TextWebSocketCommands.cs

@@ -15,9 +15,11 @@ namespace Discord.API.Models
 		{
 			[JsonProperty(PropertyName = "op")]
 			public int Operation;
-			[JsonProperty(PropertyName = "t")]
+			[JsonProperty(PropertyName = "t", NullValueHandling = NullValueHandling.Ignore)]
 			public string Type;
-			[JsonProperty(PropertyName = "d")]
+			[JsonProperty(PropertyName = "s", NullValueHandling = NullValueHandling.Ignore)]
+			public int? Sequence;
+			[JsonProperty(PropertyName = "d", NullValueHandling = NullValueHandling.Ignore)]
 			public object Payload;
 		}
 		internal abstract class WebSocketMessage<T> : WebSocketMessage
@@ -78,5 +80,16 @@ namespace Discord.API.Models
 				public string SelfDeaf;
 			}
 		}
+		public sealed class Resume : WebSocketMessage<Resume.Data>
+		{
+			public Resume() : base(6) { }
+			public class Data
+			{
+				[JsonProperty(PropertyName = "session_id")]
+				public string SessionId;
+				[JsonProperty(PropertyName = "seq")]
+				public int Sequence;
+			}
+		}
 	}
 }

src/Discord.Net/API/Models/TextWebSocketEvents.cs

@@ -36,6 +36,12 @@ namespace Discord.API.Models
 			public int HeartbeatInterval;
 		}
 
+		public sealed class Redirect
+		{
+			[JsonProperty(PropertyName = "url")]
+			public string Url;
+		}
+
 		//Servers
 		public sealed class GuildCreate : ExtendedServerInfo { }
 		public sealed class GuildUpdate : ServerInfo { }

src/Discord.Net/DiscordDataSocket.cs

@@ -12,6 +12,8 @@ namespace Discord
 	internal sealed partial class DiscordDataSocket : DiscordWebSocket
 	{
 		private readonly ManualResetEventSlim _connectWaitOnLogin, _connectWaitOnLogin2;
+		private string _lastSession, _redirectServer;
+		private int _lastSeq;
 
 		public DiscordDataSocket(DiscordClient client, int timeout, int interval, bool isDebug)
 			: base(client, timeout, interval, isDebug)
@@ -20,10 +22,13 @@ namespace Discord
 			_connectWaitOnLogin2 = new ManualResetEventSlim(false);
         }
 
-		public override Task ConnectAsync(string url)
+		public override async Task ConnectAsync(string url)
 		{
-			BeginConnect();
+			_lastSeq = 0;
-			return base.ConnectAsync(url);
+			_lastSession = null;
+			_redirectServer = null;
+			await BeginConnect();
+			await base.ConnectAsync(url);
 		}
 		public async Task Login(string token)
 		{
@@ -65,6 +70,8 @@ namespace Discord
 		protected override Task ProcessMessage(string json)
 		{
 			var msg = JsonConvert.DeserializeObject<WebSocketMessage>(json);
+			if (msg.Sequence.HasValue)
+				_lastSeq = msg.Sequence.Value;
 			switch (msg.Operation)
 			{
 				case 0:
@@ -72,6 +79,7 @@ namespace Discord
 						if (msg.Type == "READY")
 						{
 							var payload = (msg.Payload as JToken).ToObject<TextWebSocketEvents.Ready>();
+							_lastSession = payload.SessionId;
 							_heartbeatInterval = payload.HeartbeatInterval;
 							QueueMessage(new TextWebSocketCommands.UpdateStatus());
 							//QueueMessage(GetKeepAlive());
@@ -82,6 +90,15 @@ namespace Discord
 							_connectWaitOnLogin2.Set(); //Post-Event
 					}
 					break;
+				case 7:
+					{
+						var payload = (msg.Payload as JToken).ToObject<TextWebSocketEvents.Redirect>();
+						if (_isDebug)
+							RaiseOnDebugMessage(DebugMessageType.Connection, $"Redirected to {payload.Url}.");
+						_host = payload.Url;
+						DisconnectInternal(new Exception("Server is redirecting."), true);
+					}
+					break;
 				default:
 					if (_isDebug)
 						RaiseOnDebugMessage(DebugMessageType.WebSocketUnknownOpCode, "Unknown Opcode: " + msg.Operation);
@@ -107,5 +124,17 @@ namespace Discord
 			var joinVoice = new TextWebSocketCommands.JoinVoice();
 			QueueMessage(joinVoice);
 		}
+
+		protected override void OnConnect()
+		{
+			if (_redirectServer != null)
+			{
+				var resumeMsg = new TextWebSocketCommands.Resume();
+				resumeMsg.Payload.SessionId = _lastSession;
+				resumeMsg.Payload.Sequence = _lastSeq;
+				SendMessage(resumeMsg, _disconnectToken.Token);
+			}
+			_redirectServer = null;
+		}
 	}
 }

src/Discord.Net/DiscordVoiceSocket.cs

@@ -128,7 +128,7 @@ namespace Discord
 
 		public new async Task BeginConnect()
 		{
-			base.BeginConnect();
+			await base.BeginConnect();
 			var cancelToken = _disconnectToken.Token;
 
 			await Task.Yield();

src/Discord.Net/DiscordWebSocket.cs

@@ -40,14 +40,15 @@ namespace Discord
 			_sendQueue = new ConcurrentQueue<byte[]>();
 		}
 
-		protected void BeginConnect()
+		protected virtual async Task BeginConnect()
 		{
+			await DisconnectAsync();
 			_disconnectToken = new CancellationTokenSource();
 			_disconnectReason = null;
 		}
 		public virtual async Task ConnectAsync(string url)
 		{
-			await DisconnectAsync();
+			//await DisconnectAsync();
 
 			var cancelToken = _disconnectToken.Token;
 
@@ -152,7 +153,7 @@ namespace Discord
                         try
 						{
 							result = await _webSocket.ReceiveAsync(new ArraySegment<byte>(buffer), cancelToken);
-						}
+                        }
 						catch (Win32Exception ex) 
 						when (ex.HResult == HR_TIMEOUT)
 						{