// returns the response
public string Send(string theLocalPath, int theSequenceNumber, string theMessage)
{
ThreadSemaphore semaphore = null;
lock (this)
{
// we use a lock here, to prevent concurrent requests
// from getting mixed together on their way out
connection.Connect();
connection.LastActivity = DateTime.Now;
HttpRequest request = new HttpRequest(connection.Socket);
request.Post(theLocalPath, theSequenceNumber, theMessage);
semaphore = blockedRequests.Add(theSequenceNumber, theMessage);
}
// block until the response arrives, or a timeout occurs
if (!semaphore.Wait(rxTimeout))
{
throw new Exception("No response received");
}
// get the response from the semaphore
byte[] response = semaphore.response;
blockedRequests.Remove(theSequenceNumber);
return(Encoding.UTF8.GetString(response));
}
public void Remove(int theSequenceNumber)
{
lock (this)
{
ThreadSemaphore semaphore = blockedRequests[theSequenceNumber] as ThreadSemaphore;
blockedRequests.Remove(theSequenceNumber);
semaphore.inUse = false;
}
}
public RequestQueue()
{
// we support up to 500 concurrent requests. The value is arbitrary
semaphores = new ThreadSemaphore[500];
for (int i = 0; i < semaphores.Length; i++)
{
ThreadSemaphore semaphore = new ThreadSemaphore();
semaphore.requestEvent = new ManualResetEvent(false);
semaphores[i] = semaphore;
}
}
public ThreadSemaphore Add(int theSequenceNumber, string theRequest)
{
lock (this)
{
ThreadSemaphore semaphore = GetFirstAvailableSemaphore();
blockedRequests.Add(theSequenceNumber, semaphore);
semaphore.requestEvent.Reset();
semaphore.sequenceNumber = theSequenceNumber;
semaphore.request = theRequest;
semaphore.response = null;
semaphore.startTime = DateTime.Now;
return(semaphore);
}
}
void HandleResponse(Socket theSocket)
{
// read the response
HttpResponse response = new HttpResponse(theSocket);
response.Get();
// get the semaphore for the blocked request thread
ThreadSemaphore semaphore = blockedRequests.Get(response.SequenceNumber);
if (semaphore == null)
{
throw new Exception("No pending request found for response");
}
// save the response in the semaphore
semaphore.response = response.Body;
// unblock the request thread waiting for this response
semaphore.Signal();
}
