/// <inheritdoc/>
public async Task <GatewayConnectionResult> DisconnectAsync
(
bool reconnectionIntended,
CancellationToken ct = default
)
{
if (_clientWebSocket is null)
{
return(GatewayConnectionResult.FromError("The transport service is not connected."));
}
switch (_clientWebSocket.State)
{
case WebSocketState.Open:
case WebSocketState.CloseReceived:
case WebSocketState.CloseSent:
{
try
{
// 1012 is used here instead of normal closure, because close codes 1000 and 1001 don't
// allow for reconnection. 1012 is referenced in the websocket protocol as "Service restart",
// which makes sense for our use case.
var closeCode = reconnectionIntended
? (WebSocketCloseStatus)1012
: WebSocketCloseStatus.NormalClosure;
await _clientWebSocket.CloseAsync
(
closeCode,
"Terminating connection by user request.",
ct
);
}
catch (WebSocketException)
{
// Most likely due to some kind of premature or forced disconnection; we'll live with it
}
break;
}
}
_clientWebSocket.Dispose();
_clientWebSocket = null;
this.IsConnected = false;
return(GatewayConnectionResult.FromSuccess());
}
/// <inheritdoc />
public async Task <GatewayConnectionResult> ConnectAsync(Uri endpoint, CancellationToken ct = default)
{
if (_clientWebSocket is not null)
{
return(GatewayConnectionResult.FromError("The transport service is already connected."));
}
var socket = _services.GetRequiredService <ClientWebSocket>();
try
{
await socket.ConnectAsync(endpoint, ct);
switch (socket.State)
{
case WebSocketState.Open:
case WebSocketState.Connecting:
{
break;
}
default:
{
socket.Dispose();
return(GatewayConnectionResult.FromError("Failed to connect to the endpoint."));
}
}
}
catch (Exception e)
{
socket.Dispose();
return(GatewayConnectionResult.FromError(e));
}
_clientWebSocket = socket;
this.IsConnected = true;
return(GatewayConnectionResult.FromSuccess());
}
/// <summary>
/// Starts and connects the gateway client.
/// </summary>
/// <remarks>
/// This task will not complete until cancelled (or faulted), maintaining the connection for the duration of it.
///
/// If the gateway client encounters a fatal problem during the execution of this task, it will return with a
/// failed result. If a shutdown is requested, it will gracefully terminate the connection and return a
/// successful result.
/// </remarks>
/// <param name="stopRequested">A token by which the caller can request this method to stop.</param>
/// <returns>A gateway connection result which may or may not have succeeded.</returns>
public async Task <GatewayConnectionResult> RunAsync(CancellationToken stopRequested)
{
try
{
if (_connectionStatus != GatewayConnectionStatus.Offline)
{
return(GatewayConnectionResult.FromError("Already connected."));
}
// Until cancellation has been requested or we hit a fatal error, reconnections should be attempted.
_disconnectRequestedSource.Dispose();
_disconnectRequestedSource = new CancellationTokenSource();
while (!stopRequested.IsCancellationRequested)
{
var iterationResult = await RunConnectionIterationAsync(stopRequested);
if (iterationResult.IsSuccess)
{
continue;
}
// Something has gone wrong. Close the socket, and handle it
// Terminate the send and receive tasks
_disconnectRequestedSource.Cancel();
// The results of the send and receive tasks are discarded here, because the iteration result will
// contain whichever of them failed if any of them did
_ = await _sendTask;
_ = await _receiveTask;
if (_transportService.IsConnected)
{
var disconnectResult = await _transportService.DisconnectAsync(stopRequested.IsCancellationRequested, stopRequested);
if (!disconnectResult.IsSuccess)
{
// Couldn't disconnect cleanly :(
return(disconnectResult);
}
}
// Finish up the responders
foreach (var runningResponder in _runningResponderDispatches)
{
await FinalizeResponderDispatchAsync(runningResponder);
}
if (stopRequested.IsCancellationRequested)
{
// The user requested a termination, and we don't intend to reconnect.
return(iterationResult);
}
if (ShouldReconnect(iterationResult, out var shouldTerminate, out var withNewSession))
{
if (withNewSession)
{
_sessionID = null;
_connectionStatus = GatewayConnectionStatus.Disconnected;
}
else
{
_connectionStatus = GatewayConnectionStatus.Disconnected;
}
}
else if (shouldTerminate)
{
return(iterationResult);
}
// This token's been cancelled, we'll need a new one to reconnect.
_disconnectRequestedSource.Dispose();
_disconnectRequestedSource = new();
}
