private void OpenConnection(IConnection connection,
string data,
CancellationToken disconnectToken,
Action initializeCallback,
Action <Exception> errorCallback)
{
// If we're reconnecting add /connect to the url
bool reconnecting = initializeCallback == null;
var callbackInvoker = new ThreadSafeInvoker();
var requestDisposer = new Disposer();
var url = (reconnecting ? connection.Url : connection.Url + "connect") + GetReceiveQueryString(connection, data);
connection.Trace(TraceLevels.Events, "SSE: GET {0}", url);
HttpClient.Get(url, req =>
{
_request = req;
connection.PrepareRequest(_request);
_request.Accept = "text/event-stream";
}).ContinueWith(task =>
{
if (task.IsFaulted)
{
Exception exception = task.Exception.Unwrap();
if (!ExceptionHelper.IsRequestAborted(exception))
{
if (errorCallback != null)
{
callbackInvoker.Invoke((cb, ex) => cb(ex), errorCallback, exception);
}
else if (reconnecting)
{
// Only raise the error event if we failed to reconnect
connection.OnError(exception);
Reconnect(connection, data, disconnectToken);
}
}
requestDisposer.Dispose();
}
else
{
var response = task.Result;
Stream stream = response.GetStream();
var eventSource = new EventSourceStreamReader(connection, stream);
bool retry = true;
var esCancellationRegistration = disconnectToken.SafeRegister(state =>
{
retry = false;
((IRequest)state).Abort();
},
_request);
eventSource.Opened = () =>
{
// If we're not reconnecting, then we're starting the transport for the first time. Trigger callback only on first start.
if (!reconnecting)
{
callbackInvoker.Invoke(initializeCallback);
}
else if (connection.ChangeState(ConnectionState.Reconnecting, ConnectionState.Connected))
{
// Raise the reconnect event if the connection comes back up
connection.OnReconnected();
}
};
eventSource.Message = sseEvent =>
{
if (sseEvent.EventType == EventType.Data)
{
if (sseEvent.Data.Equals("initialized", StringComparison.OrdinalIgnoreCase))
{
return;
}
bool timedOut;
bool disconnected;
TransportHelper.ProcessResponse(connection, sseEvent.Data, out timedOut, out disconnected);
if (disconnected)
{
retry = false;
connection.Disconnect();
}
}
};
eventSource.Closed = exception =>
{
if (exception != null)
{
// Check if the request is aborted
bool isRequestAborted = ExceptionHelper.IsRequestAborted(exception);
if (!isRequestAborted)
{
// Don't raise exceptions if the request was aborted (connection was stopped).
connection.OnError(exception);
}
}
requestDisposer.Dispose();
esCancellationRegistration.Dispose();
response.Dispose();
if (AbortResetEvent != null)
{
AbortResetEvent.Set();
}
else if (retry)
{
Reconnect(connection, data, disconnectToken);
}
};
eventSource.Start();
}
});
var requestCancellationRegistration = disconnectToken.SafeRegister(state =>
{
if (state != null)
{
// This will no-op if the request is already finished.
((IRequest)state).Abort();
}
if (errorCallback != null)
{
callbackInvoker.Invoke((cb, token) =>
{
#if NET35 || WINDOWS_PHONE
cb(new OperationCanceledException(Resources.Error_ConnectionCancelled));
#else
cb(new OperationCanceledException(Resources.Error_ConnectionCancelled, token));
#endif
}, errorCallback, disconnectToken);
}
}, _request);
requestDisposer.Set(requestCancellationRegistration);
if (errorCallback != null)
{
TaskAsyncHelper.Delay(ConnectionTimeout).Then(() =>
{
callbackInvoker.Invoke((conn, cb) =>
{
// Abort the request before cancelling
_request.Abort();
// Connection timeout occurred
cb(new TimeoutException());
},
connection,
errorCallback);
});
}
}
private void PollingSetup(IConnection connection,
string data,
CancellationToken disconnectToken,
PollingRequestHandler requestHandler)
{
// These are created new on each poll
var reconnectInvoker = new ThreadSafeInvoker();
var requestDisposer = new Disposer();
requestHandler.ResolveUrl = () =>
{
var url = connection.Url;
if (connection.MessageId == null)
{
url += "connect";
}
else if (IsReconnecting(connection))
{
url += "reconnect";
}
else
{
url += "poll";
}
url += GetReceiveQueryString(connection, data);
return(url);
};
requestHandler.PrepareRequest += req =>
{
connection.PrepareRequest(req);
};
requestHandler.OnMessage += message =>
{
var shouldReconnect = false;
var disconnectedReceived = false;
connection.Trace(TraceLevels.Messages, "LP: OnMessage({0})", message);
TransportHelper.ProcessResponse(connection,
message,
out shouldReconnect,
out disconnectedReceived);
if (IsReconnecting(connection))
{
// If the timeout for the reconnect hasn't fired as yet just fire the
// event here before any incoming messages are processed
TryReconnect(connection, reconnectInvoker);
}
if (shouldReconnect)
{
// Transition into reconnecting state
connection.EnsureReconnecting();
}
if (AbortResetEvent != null)
{
AbortResetEvent.Set();
}
else if (disconnectedReceived)
{
connection.Disconnect();
}
};
requestHandler.OnError += exception =>
{
reconnectInvoker.Invoke();
// Transition into reconnecting state
connection.EnsureReconnecting();
// Sometimes a connection might have been closed by the server before we get to write anything
// so just try again and raise OnError.
if (!ExceptionHelper.IsRequestAborted(exception) && !(exception is IOException))
{
connection.OnError(exception);
}
else
{
// If we aborted purposely then we need to stop the request handler
requestHandler.Stop();
}
};
requestHandler.OnPolling += () =>
{
// Capture the cleanup within a closure so it can persist through multiple requests
TryDelayedReconnect(connection, reconnectInvoker);
requestDisposer.Set(disconnectToken.SafeRegister(state =>
{
reconnectInvoker.Invoke();
requestHandler.Stop();
}, null));
};
requestHandler.OnAfterPoll = exception =>
{
requestDisposer.Dispose();
requestDisposer = new Disposer();
reconnectInvoker = new ThreadSafeInvoker();
if (exception != null)
{
// Delay polling by the error delay
return(TaskAsyncHelper.Delay(ErrorDelay));
}
return(TaskAsyncHelper.Empty);
};
}