private void CloseConnection(HttpResponseSender clientContext)
{
using (EneterTrace.Entering())
{
if (!clientContext.IsDisposed)
{
try
{
// Send close connection message.
object anEncodedMessage = myProtocolFormatter.EncodeCloseConnectionMessage(clientContext.ResponseReceiverId);
clientContext.SendResponseMessage(anEncodedMessage);
}
catch (Exception err)
{
EneterTrace.Warning("failed to send the close message.", err);
}
// Note: the client context will be removed by the timer.
// The reason is the client can still poll for messages which are stored in the HttpResponseSender.
clientContext.Dispose();
}
}
}
private void HandleConnection(HttpListenerContext httpRequestContext)
{
using (EneterTrace.Entering())
{
// If polling. (when client polls to get response messages)
if (httpRequestContext.Request.HttpMethod.ToUpperInvariant() == "GET")
{
// Get responseReceiverId.
string[] aQueryItems = httpRequestContext.Request.Url.Query.Split('&');
if (aQueryItems.Length > 0)
{
string aResponseReceiverId = aQueryItems[0].Substring(4);
// Find the client.
HttpResponseSender aClientContext;
using (ThreadLock.Lock(myConnectedClients))
{
aClientContext = myConnectedClients.FirstOrDefault(x => x.ResponseReceiverId == aResponseReceiverId);
}
if (aClientContext != null)
{
// Response collected messages.
byte[] aMessages = aClientContext.DequeueCollectedMessages();
if (aMessages != null)
{
httpRequestContext.SendResponseMessage(aMessages);
}
}
else
{
// Note: This happens when the polling runs and the connection is not open yet.
// It is a normal situation because the polling thread on the client starts
// slightly before the connection is open.
}
}
else
{
EneterTrace.Warning("Incorrect query format detected for HTTP GET request.");
// The request was not processed.
httpRequestContext.Response.StatusCode = 404;
}
}
else
// Client sends a request message.
{
byte[] aMessage = httpRequestContext.GetRequestMessage();
IPEndPoint anEndPoint = httpRequestContext.Request.RemoteEndPoint;
string aClientIp = (anEndPoint != null) ? anEndPoint.Address.ToString() : "";
ProtocolMessage aProtocolMessage = myProtocolFormatter.DecodeMessage(aMessage);
bool anIsProcessingOk = true;
if (aProtocolMessage != null && !string.IsNullOrEmpty(aProtocolMessage.ResponseReceiverId))
{
MessageContext aMessageContext = new MessageContext(aProtocolMessage, aClientIp);
if (aProtocolMessage.MessageType == EProtocolMessageType.OpenConnectionRequest)
{
using (ThreadLock.Lock(myConnectedClients))
{
HttpResponseSender aClientContext = myConnectedClients.FirstOrDefault(x => x.ResponseReceiverId == aProtocolMessage.ResponseReceiverId);
if (aClientContext != null && aClientContext.IsDisposed)
{
// The client with the same id exists but was closed and disposed.
// It is just that the timer did not remove it. So delete it now.
myConnectedClients.Remove(aClientContext);
// Indicate the new client context shall be created.
aClientContext = null;
}
if (aClientContext == null)
{
aClientContext = new HttpResponseSender(aProtocolMessage.ResponseReceiverId, aClientIp);
myConnectedClients.Add(aClientContext);
// If this is the only sender then start the timer measuring the inactivity to detect if the client is disconnected.
// If it is not the only sender, then the timer is already running.
if (myConnectedClients.Count == 1)
{
myResponseReceiverInactivityTimer.Change(myResponseReceiverInactivityTimeout, -1);
}
}
else
{
EneterTrace.Warning(TracedObject + "could not open connection for client '" + aProtocolMessage.ResponseReceiverId + "' because the client with same id is already connected.");
anIsProcessingOk = false;
}
}
}
else if (aProtocolMessage.MessageType == EProtocolMessageType.CloseConnectionRequest)
{
using (ThreadLock.Lock(myConnectedClients))
{
HttpResponseSender aClientContext = myConnectedClients.FirstOrDefault(x => x.ResponseReceiverId == aProtocolMessage.ResponseReceiverId);
if (aClientContext != null)
{
// Note: the disconnection comes from the client.
// It means the client closed the connection and will not poll anymore.
// Therefore the client context can be removed.
myConnectedClients.Remove(aClientContext);
aClientContext.Dispose();
}
}
}
if (anIsProcessingOk)
{
NotifyMessageContext(aMessageContext);
}
}
if (!anIsProcessingOk)
{
// The request was not processed.
httpRequestContext.Response.StatusCode = 404;
}
}
}
}