Better Dispose pattern for WebSocketConnection (#673)

Author: Shane32

src/Transports.Subscriptions.WebSockets/GraphQLWebSocketsMiddleware.cs

@@ -61,8 +61,9 @@ await socket.CloseAsync(
                 using (_logger.BeginScope($"GraphQL websocket connection: {context.Connection.Id}"))
                 {
                     var connectionFactory = context.RequestServices.GetRequiredService<IWebSocketConnectionFactory<TSchema>>();
-                    var connection = connectionFactory.CreateConnection(socket, context.Connection.Id);
+                    using var connection = connectionFactory.CreateConnection(socket, context.Connection.Id);
 
+                    // Wait until the websocket has disconnected (and all subscriptions ended)
                     await connection.Connect();
                 }
             }

src/Transports.Subscriptions.WebSockets/WebSocketConnection.cs

@@ -1,9 +1,10 @@
+using System;
 using System.Threading.Tasks;
 using GraphQL.Server.Transports.Subscriptions.Abstractions;
 
 namespace GraphQL.Server.Transports.WebSockets
 {
-    public class WebSocketConnection
+    public class WebSocketConnection : IDisposable
     {
         private readonly WebSocketTransport _transport;
         private readonly SubscriptionServer _server;
@@ -18,16 +19,14 @@ public WebSocketConnection(
 
         public virtual async Task Connect()
         {
-            try
-            {
-                await _server.OnConnect();
-                await _server.OnDisconnect();
-                await _transport.CloseAsync();
-            }
-            finally
-            {
-                _transport.Dispose();
-            }
+            await _server.OnConnect();
+            await _server.OnDisconnect();
+            await _transport.CloseAsync();
+        }
+
+        public void Dispose()
+        {
+            _transport.Dispose();
         }
     }
 }

tests/ApiApprovalTests/GraphQL.Server.Transports.Subscriptions.WebSockets.approved.txt

@@ -18,10 +18,11 @@ namespace GraphQL.Server.Transports.WebSockets
     {
         GraphQL.Server.Transports.WebSockets.WebSocketConnection CreateConnection(System.Net.WebSockets.WebSocket socket, string connectionId);
     }
-    public class WebSocketConnection
+    public class WebSocketConnection : System.IDisposable
     {
         public WebSocketConnection(GraphQL.Server.Transports.WebSockets.WebSocketTransport transport, GraphQL.Server.Transports.Subscriptions.Abstractions.SubscriptionServer subscriptionServer) { }
         public virtual System.Threading.Tasks.Task Connect() { }
+        public void Dispose() { }
     }
     public class WebSocketConnectionFactory<TSchema> : GraphQL.Server.Transports.WebSockets.IWebSocketConnectionFactory<TSchema>
         where TSchema : GraphQL.Types.ISchema