/// <summary>
/// Receive request context from frontend and send request to service host
/// </summary>
/// <param name="request">indicating the request message</param>
/// <param name="callback">indicating the callback</param>
public void ReceiveRequest(Message request, IDuplexCallbackService callback)
{
// Try to get a dispatcher from the dispatcher list
// Put the loadbalancing logic here to choose a service host for dispatching messages
Dispatcher dispatcher;
while (true)
{
if (this.dispatcherList.Count > 0)
{
lock (this.dispatcherList)
{
if (this.dispatcherList.Count > 0)
{
// Randomly choose a service client as a sample dispatching tacitc
Random r = new Random();
int index = r.Next(this.dispatcherList.Count);
dispatcher = this.dispatcherList.Values[index];
break;
}
}
}
// Sleep 1 second to wait for service host ready
Thread.Sleep(1000);
}
dispatcher.ProcessRequest(request, callback);
}
/// <summary>
/// Callback raised when response is received
/// </summary>
/// <param name="result">indicating the async result</param>
private void ReceiveResponse(IAsyncResult result)
{
object[] objArr = result.AsyncState as object[];
UniqueId messageId = objArr[0] as UniqueId;
IDuplexCallbackService callback = objArr[1] as IDuplexCallbackService;
Message response;
try
{
lock (this.client)
{
response = this.client.EndProcessMessage(result);
}
}
catch (Exception e)
{
// Communication/Timeout/EndpointNotFound exception could throw here
// Build fault message instead and send back to client
Trace.TraceError("[ServiceClientManager] Failed to process the message: {0}", e);
response = this.BuildFaultMessage(messageId, e);
}
try
{
// Send back response to client side
callback.SendResponse(response);
}
catch (Exception e)
{
// Failed to send response
// Swallow the exception and log it
Trace.TraceError("[ServiceClientManager] Failed to send back response: {0}", e);
}
}
/// <summary>
/// Process request
/// </summary>
/// <param name="request">indicating the request message</param>
/// <param name="callback">indicating the callback</param>
public void ProcessRequest(Message request, IDuplexCallbackService callback)
{
// Send request to service host for processing
lock (this.client)
{
this.client.BeginProcessMessage(request, this.ReceiveResponse, new object[] { request.Headers.MessageId, callback });
}
}
