public virtual string Start()
{
string ret = null;
LOG.Debug("Starting HTTP server listening on port {0}...", Port);
try
{
Listener.Start();
int timeoutSeconds = 3;
bool isListening = CheckIsListening(timeoutSeconds);
if (!isListening)
{
LOG.Error("Failed to start HTTP server listening on port {0}.", Port);
return("Failed to start HTTP server");
}
LOG.Debug("Calling Listener.BeginGetContext from main thread...");
RequestProcessorParameter arguments =
new RequestProcessorParameter(this.Listener, this.RequestHandler);
Listener.BeginGetContext(ProcessHttpRequest, arguments);
LOG.Debug("Continuing main thread after Listener.BeginGetContext...");
LOG.Debug("HTTP server listening on port {0} has started.", Port);
return("OK");
}
catch (Exception e)
{
LOG.Error(e, "Failed to start HTTP server listening on port {0}.", Port);
return("Failed to start HTTP server: " + e.Message);
}
}
void ProcessHttpRequest(IAsyncResult result)
{
RequestProcessorParameter arguments = (RequestProcessorParameter)result.AsyncState;
HttpListener listener = arguments.Listener;
IHttpRequestHandler requestHandler = arguments.RequestHandler;
LOG.Debug("Handling HTTP request...");
if (listener == null)
{
LOG.Error("Unable to handle HTTP request: No listener supplied.");
return;
}
if (requestHandler == null)
{
LOG.Error("Unable to handle HTTP request: No request handler supplied.");
// No point in calling listener.BeginGetContext since there is no request handler
// to pass in as argument.
return;
}
if (requestHandler.MethodHandlers == null || requestHandler.MethodHandlers.Count == 0)
{
LOG.Error("Unable to handle HTTP request: No HTTP method handlers supplied.");
// No point in calling listener.BeginGetContext since there is no method handler
// to pass in as argument.
return;
}
HttpListenerContext context = null;
try
{
context = listener.EndGetContext(result);
LOG.Debug("Listener.EndGetContext complete.");
}
catch (Exception ex)
{
LOG.Debug("{0}: {1}", ex.GetType().Name, ex.Message);
// If the main thread has closed the listener then Listener.EndGetContext throws
// an ObjectDisposedException or an HttpListenerException. There is no neat way
// around this, such as checking IsDisposed or IsDisposing, since HttpListener
// doesn't have any properties like that. So the only way to deal with it is to
// catch the exception and do nothing with it, allowing execution to continue.
if (ex is ObjectDisposedException || ex is HttpListenerException)
{
LOG.Debug("Exiting ProcessHttpRequest method.");
return;
}
}
LOG.Debug("Calling HttpRequestHandler to process request...");
requestHandler.ProcessHttpRequest(context);
LOG.Debug("Completed handling HTTP of request.");
LOG.Debug("Calling listener.BeginGetContext from within request handler...");
listener.BeginGetContext(ProcessHttpRequest, arguments);
LOG.Debug("Request handler finished.");
}
