Added checking if the handshake response is a Redirect

websocket-sharp/WebSocket.cs

@@ -587,7 +587,9 @@ namespace WebSocketSharp
     private string checkIfValidHandshakeResponse (HttpResponse response)
     {
       var headers = response.Headers;
-      return response.IsUnauthorized
+      return response.IsRedirect
+             ? "A Redirect response was received."
+             : response.IsUnauthorized
                ? "An HTTP authentication is required."
                : !response.IsWebSocketResponse
                  ? "Not a WebSocket connection response."
@@ -1235,6 +1237,13 @@ namespace WebSocketSharp
         }
       }
 
+      if (res.IsRedirect) {
+        var url = res.Headers["Location"];
+        _logger.Warn (
+          String.Format (
+            "Received a Redirect response that specifies the Location to '{0}'.", url));
+      }
+
       return res;
     }