/// <summary>
/// Fully stops the polling loop.
/// </summary>
private void StopPolling()
{
lock (_stopLock)
{
if (Interlocked.Exchange(ref _running, 0) == 1)
{
_disconnectRegistration.Dispose();
// Complete any ongoing calls to Abort()
// If someone calls Abort() later, have it no-op
AbortHandler.CompleteAbort();
if (_currentRequest != null)
{
// This will no-op if the request is already finished
_currentRequest.Abort();
}
}
}
}
private void PollingSetup(IConnection connection,
string data,
CancellationToken disconnectToken,
PollingRequestHandler requestHandler,
Action onInitialized)
{
// reconnectInvoker is created new on each poll
var reconnectInvoker = new ThreadSafeInvoker();
var disconnectRegistration = disconnectToken.SafeRegister(state =>
{
reconnectInvoker.Invoke();
requestHandler.Stop();
}, null);
requestHandler.ResolveUrl = () =>
{
var url = connection.Url;
if (connection.MessageId == null)
{
url += "connect";
connection.Trace(TraceLevels.Events, "LP Connect: {0}", url);
}
else if (IsReconnecting(connection))
{
url += "reconnect";
connection.Trace(TraceLevels.Events, "LP Reconnect: {0}", url);
}
else
{
url += "poll";
connection.Trace(TraceLevels.Events, "LP Poll: {0}", url);
}
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,
onInitialized);
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 (disconnectedReceived)
{
connection.Trace(TraceLevels.Messages, "Disconnect command received from server.");
connection.Disconnect();
}
};
requestHandler.OnError += exception =>
{
reconnectInvoker.Invoke();
if (!TransportHelper.VerifyLastActive(connection))
{
return;
}
// 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
{
requestHandler.Stop();
}
};
requestHandler.OnPolling += () =>
{
// Capture the cleanup within a closure so it can persist through multiple requests
TryDelayedReconnect(connection, reconnectInvoker);
};
requestHandler.OnAfterPoll = exception =>
{
if (AbortHandler.TryCompleteAbort())
{
// Abort() was called, so don't reconnect
requestHandler.Stop();
}
else
{
reconnectInvoker = new ThreadSafeInvoker();
if (exception != null)
{
// Delay polling by the error delay
return(TaskAsyncHelper.Delay(ErrorDelay));
}
}
return(TaskAsyncHelper.Empty);
};
requestHandler.OnAbort += _ =>
{
disconnectRegistration.Dispose();
// Complete any ongoing calls to Abort()
// If someone calls Abort() later, have it no-op
AbortHandler.CompleteAbort();
};
}
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();
Action initializeInvoke = () =>
{
callbackInvoker.Invoke(initializeCallback);
};
var url = connection.Url + (reconnecting ? "reconnect" : "connect") + GetReceiveQueryString(connection, data);
connection.Trace(TraceLevels.Events, "SSE: GET {0}", url);
HttpClient.Get(url, req =>
{
_request = req;
_request.Accept = "text/event-stream";
connection.PrepareRequest(_request);
}, isLongRunning: true).ContinueWith(task =>
{
if (task.IsFaulted || task.IsCanceled)
{
Exception exception;
if (task.IsCanceled)
{
exception = new OperationCanceledException(Resources.Error_TaskCancelledException);
}
else
{
exception = task.Exception.Unwrap();
}
if (errorCallback != null)
{
callbackInvoker.Invoke((cb, ex) => cb(ex), errorCallback, exception);
}
else if (!_stop && reconnecting)
{
// Only raise the error event if we failed to reconnect
connection.OnError(exception);
Reconnect(connection, data, disconnectToken);
}
requestDisposer.Dispose();
}
else
{
// If the disconnect token is canceled the response to the task doesn't matter.
if (disconnectToken.IsCancellationRequested)
{
return;
}
var response = task.Result;
Stream stream = response.GetStream();
var eventSource = new EventSourceStreamReader(connection, stream);
var esCancellationRegistration = disconnectToken.SafeRegister(state =>
{
_stop = true;
((IRequest)state).Abort();
},
_request);
eventSource.Opened = () =>
{
// This will noop if we're not in the reconnecting state
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 shouldReconnect;
bool disconnected;
TransportHelper.ProcessResponse(connection, sseEvent.Data, out shouldReconnect, out disconnected, initializeInvoke);
if (disconnected)
{
_stop = true;
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 (_stop)
{
AbortHandler.CompleteAbort();
}
else if (AbortHandler.TryCompleteAbort())
{
// Abort() was called, so don't reconnect
}
else
{
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
cb(new OperationCanceledException(Resources.Error_ConnectionCancelled, token));
#else
cb(new OperationCanceledException(Resources.Error_ConnectionCancelled));
#endif
}, errorCallback, disconnectToken);
}
}, _request);
requestDisposer.Set(requestCancellationRegistration);
}
internal void OpenConnection(IConnection connection, string data, CancellationToken disconnectToken, bool reconnecting)
{
// If we're reconnecting add /connect to the url
var url = reconnecting
? UrlBuilder.BuildReconnect(connection, Name, data)
: UrlBuilder.BuildConnect(connection, Name, data);
connection.Trace(TraceLevels.Events, "SSE: GET {0}", url);
var getTask = HttpClient.Get(url, req =>
{
_request = req;
_request.Accept = "text/event-stream";
connection.PrepareRequest(_request);
}, isLongRunning: true);
var requestCancellationRegistration = disconnectToken.SafeRegister(state =>
{
_stop = true;
// This will no-op if the request is already finished.
((IRequest)state).Abort();
}, _request);
getTask.ContinueWith(task =>
{
if (task.IsFaulted || task.IsCanceled)
{
var exception = task.IsCanceled
? new OperationCanceledException(Resources.Error_TaskCancelledException)
: task.Exception.Unwrap();
if (!reconnecting)
{
// It shouldn't be possible for Start to have already succeeded at this point.
TryFailStart(exception);
}
else if (!_stop)
{
// Only raise the error event if the error wasn't raised from Start and we're reconnecting.
connection.OnError(exception);
Reconnect(connection, data, disconnectToken);
}
requestCancellationRegistration.Dispose();
}
else
{
// If the disconnect token is canceled the response to the task doesn't matter.
if (disconnectToken.IsCancellationRequested)
{
return;
}
var response = task.Result;
Stream stream = response.GetStream();
var eventSource = new EventSourceStreamReader(connection, stream);
eventSource.Opened = () =>
{
// This will noop if we're not in the reconnecting state
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 &&
!sseEvent.Data.Equals("initialized", StringComparison.OrdinalIgnoreCase))
{
ProcessResponse(connection, sseEvent.Data);
}
};
eventSource.Closed = exception =>
{
// Make sure to try to fail start even if the disconnectToken tripped and set _stop to true.
var startFailed = TryFailStart(exception);
if (exception != null && !startFailed)
{
// Check if the request is aborted
if (!ExceptionHelper.IsRequestAborted(exception))
{
// Don't raise exceptions if the request was aborted (connection was stopped).
connection.OnError(exception);
}
}
requestCancellationRegistration.Dispose();
response.Dispose();
if (_stop)
{
AbortHandler.CompleteAbort();
}
else if (!AbortHandler.TryCompleteAbort() && !startFailed)
{
// If Abort() was called or Start() failed, don't reconnect.
Reconnect(connection, data, disconnectToken);
}
};
eventSource.Start();
}
});
}