/// <summary>
/// Raise the QueryFinished event with the specified parameters
/// </summary>
/// <param name="response">Response to the query (success, failure, etc)</param>
/// <param name="queryType">Type of query that finished</param>
/// <param name="payload">Received data packet</param>
private void OnQueryFinished(UDPServerQueryState queryState, UDPPacket payload)
{
UDPServerQueryResponseHandler queryFinished = this.QueryFinished;
if (queryFinished != null)
{
queryFinished(this, queryState.QueryResponse, queryState.QueryType, payload);
}
}
/// <summary>
/// Start an asynchronous query operation
/// </summary>
/// <param name="timeout">Timeout (in seconds) to wait for a response from the server or zero for no timeout</param>
public void BeginQuery(int timeout, UDPServerQueryType queryType, IPAddress address, int queryPort)
{
remoteEndpoint = new IPEndPoint(address, queryPort);
// Start the query thread
UDPServerQueryState queryState = new UDPServerQueryState(new ParameterizedThreadStart(QueryThreadProc), new TimerCallback(QueryTimeoutCallback), queryType);
lock (activeQueryLock)
{
activeQueries.Add(queryState);
}
queryState.Start(timeout);
}
/// <summary>
/// Callback function for when the timeout timer expires
/// </summary>
/// <param name="state"></param>
private void QueryTimeoutCallback(object state)
{
UDPServerQueryState queryState = (UDPServerQueryState)state;
// Flag the timeout condition
queryState.QueryResponse = UDPServerQueryResponse.Timeout;
queryState.End();
OnQueryFinished(queryState, null);
lock (activeQueryLock)
{
activeQueries.Remove(queryState);
}
}
/// <summary>
/// Thread function where the query is actually executed. The call to Receive() is blocking and the
/// separate timer thread takes care of the timeout behaviour (if specified)
/// </summary>
private void QueryThreadProc(object oQueryState)
{
UDPServerQueryState queryState = (UDPServerQueryState)oQueryState;
try
{
// Send the query to the server
OutboundPacket query = new OutboundPacket(true);
query.Append((byte)queryState.QueryType);
Send(queryState.QueryClient, query);
// Wait for a response from the server
UDPPacket queryResponse = Receive(queryState.QueryClient);
// Stop the timeout timer
queryState.End();
if (queryState.QueryResponse == UDPServerQueryResponse.None)
{
queryState.QueryResponse = UDPServerQueryResponse.Success;
OnQueryFinished(queryState, queryResponse);
}
}
catch (ThreadAbortException) { }
catch (Exception)
{
if (queryState.QueryResponse != UDPServerQueryResponse.Timeout)
{
queryState.QueryResponse = UDPServerQueryResponse.Error;
// Stop the timeout timer
queryState.End();
OnQueryFinished(queryState, null);
}
}
lock (activeQueryLock)
{
activeQueries.Remove(queryState);
}
}
