public async Task <T> InvokeClientMethodAsync <T>(string socketId, string methodName, object[] arguments)
{
// create the method invocation descriptor.
InvocationDescriptor invocationDescriptor = new InvocationDescriptor {
MethodName = methodName, Arguments = arguments
};
// generate a unique identifier for this invocation.
invocationDescriptor.Identifier = Guid.NewGuid();
// add ourselves to the waiting list for return values.
TaskCompletionSource <InvocationResult> task = new TaskCompletionSource <InvocationResult>();
// after a timeout of 60 seconds we will cancel the task and remove it from the waiting list.
new CancellationTokenSource(1000 * 60).Token.Register(() => { _waitingRemoteInvocations.Remove(invocationDescriptor.Identifier); task.TrySetCanceled(); });
_waitingRemoteInvocations.Add(invocationDescriptor.Identifier, task);
// send the method invocation to the client.
var message = new Message()
{
MessageType = MessageType.MethodInvocation, Data = JsonConvert.SerializeObject(invocationDescriptor, _jsonSerializerSettings)
};
await SendMessageAsync(socketId, message).ConfigureAwait(false);
// wait for the return value elsewhere in the program.
InvocationResult result = await task.Task;
// ... we just got an answer.
// if we have completed successfully:
if (task.Task.IsCompleted)
{
// there was a remote exception so we throw it here.
if (result.Exception != null)
{
throw new Exception(result.Exception.Message);
}
// return the value.
// support null.
if (result.Result == null)
{
return(default(T));
}
// cast anything to T and hope it works.
return((T)result.Result);
}
// if we reach here we got cancelled or alike so throw a timeout exception.
throw new TimeoutException(); // todo: insert fancy message here.
}
public async Task SendClientErrorAsync(string socketId, string methodName, RemoteException error)
{
// create the method invocation descriptor.
InvocationResult invocationResult = new InvocationResult {
MethodName = methodName, Exception = error
};
WebSocketConnection socket = WebSocketConnectionManager.GetSocketById(socketId);
if (socket == null)
{
return;
}
invocationResult.Id = socket.NextCmdId();
var message = new Message()
{
MessageType = MessageType.MethodInvocation,
Data = JsonConvert.SerializeObject(invocationResult)
};
await SendMessageAsync(socketId, message).ConfigureAwait(false);
}
public async Task ReceiveAsync(WebSocket socket, WebSocketReceiveResult result, Message receivedMessage)
{
// method invocation request.
if (receivedMessage.MessageType == MessageType.MethodInvocation)
{
// retrieve the method invocation request.
InvocationDescriptor invocationDescriptor = null;
try
{
invocationDescriptor = JsonConvert.DeserializeObject <InvocationDescriptor>(receivedMessage.Data, _jsonSerializerSettings);
if (invocationDescriptor == null)
{
return;
}
}
catch { return; } // ignore invalid data sent to the server.
// if the unique identifier hasn't been set then the client doesn't want a return value.
if (invocationDescriptor.Identifier == Guid.Empty)
{
// invoke the method only.
try
{
await MethodInvocationStrategy.OnInvokeMethodReceivedAsync(socket, invocationDescriptor);
}
catch (Exception)
{
// we consume all exceptions.
}
}
else
{
// invoke the method and get the result.
InvocationResult invokeResult;
try
{
// create an invocation result with the results.
invokeResult = new InvocationResult()
{
Identifier = invocationDescriptor.Identifier,
Result = await MethodInvocationStrategy.OnInvokeMethodReceivedAsync(socket, invocationDescriptor),
Exception = null
};
}
// send the exception as the invocation result if there was one.
catch (Exception ex)
{
invokeResult = new InvocationResult()
{
Identifier = invocationDescriptor.Identifier,
Result = null,
Exception = new RemoteException(ex)
};
}
// send a message to the client containing the result.
var message = new Message()
{
MessageType = MessageType.MethodReturnValue,
Data = JsonConvert.SerializeObject(invokeResult, _jsonSerializerSettings)
};
await SendMessageAsync(socket, message).ConfigureAwait(false);
}
}
// method return value.
else if (receivedMessage.MessageType == MessageType.MethodReturnValue)
{
var invocationResult = JsonConvert.DeserializeObject <InvocationResult>(receivedMessage.Data, _jsonSerializerSettings);
// find the completion source in the waiting list.
if (_waitingRemoteInvocations.ContainsKey(invocationResult.Identifier))
{
// set the result of the completion source so the invoke method continues executing.
_waitingRemoteInvocations[invocationResult.Identifier].SetResult(invocationResult);
// remove the completion source from the waiting list.
_waitingRemoteInvocations.Remove(invocationResult.Identifier);
}
}
}
public async Task OnReceivedTextAsync(WebSocketConnection socket, string serializedMessage)
{
InvocationDescriptor invocationDescriptor = null;
try
{
invocationDescriptor = JsonConvert.DeserializeObject <InvocationDescriptor>(serializedMessage);
//invocationDescriptor = JsonConvert.DeserializeObject<InvocationDescriptor>(serializedMessage, _jsonSerializerSettings);
//invocationDescriptor = JsonConvert.DeserializeObject<InvocationDescriptor>(receivedMessage.Data, _jsonSerializerSettings);
if (invocationDescriptor == null)
{
return;
}
}
catch (Exception ex)
{
return;
} // ignore invalid data sent to the server.
// method invocation request.
if (invocationDescriptor.Params != null)
{
// retrieve the method invocation request.
// if the unique identifier hasn't been set then the client doesn't want a return value.
if (invocationDescriptor.Id == 0)
{
// invoke the method only.
try
{
await MethodInvocationStrategy.OnInvokeMethodReceivedAsync(socket.Id, invocationDescriptor);
}
catch (Exception)
{
// we consume all exceptions.
}
}
else
{
// invoke the method and get the result.
InvocationResult invokeResult;
try
{
// create an invocation result with the results.
invokeResult = new InvocationResult()
{
MethodName = invocationDescriptor.MethodName,
Id = invocationDescriptor.Id,
Result = await MethodInvocationStrategy.OnInvokeMethodReceivedAsync(socket.Id, invocationDescriptor),
Exception = null
};
}
// send the exception as the invocation result if there was one.
catch (Exception ex)
{
invokeResult = new InvocationResult()
{
MethodName = invocationDescriptor.MethodName,
Id = invocationDescriptor.Id,
Result = null,
Exception = new RemoteException(ex)
};
}
string json = JsonConvert.SerializeObject(invokeResult);
// send a message to the client containing the result.
var message = new Message()
{
MessageType = MessageType.MethodReturnValue,
Data = json
//Data = JsonConvert.SerializeObject(invokeResult, _jsonSerializerSettings)
};
await SendMessageAsync(socket, message).ConfigureAwait(false);
}
}
else
{
await OnResponseAsync(socket, serializedMessage);
}
}