private void FinderDiscoveryCallback(IAsyncResult ar)
{
try
{
UdpClient udpClient = (UdpClient)ar.AsyncState;
IPEndPoint alpacaBroadcastResponseEndPoint = new IPEndPoint(IPAddress.Any, Constants.DEFAULT_DISCOVERY_PORT);
// Obtain the UDP message body and convert it to a string, with remote IP address attached as well
string ReceiveString = Encoding.ASCII.GetString(udpClient.EndReceive(ar, ref alpacaBroadcastResponseEndPoint));
LogMessage($"FinderDiscoveryCallback", $"Received {ReceiveString} from Alpaca device at {alpacaBroadcastResponseEndPoint.Address.ToString()}");
// Configure the UdpClient class to accept more messages, if they arrive
udpClient.BeginReceive(FinderDiscoveryCallback, udpClient);
//Only process Alpaca device responses
if (ReceiveString.ToLowerInvariant().Contains(Constants.DISCOVERY_RESPONSE_STRING))
{
// Extract the discovery response parameters from the device's JSON response
AlpacaDiscoveryResponse discoveryResponse = JsonConvert.DeserializeObject <AlpacaDiscoveryResponse>(ReceiveString);
IPEndPoint alpacaApiEndpoint = new IPEndPoint(alpacaBroadcastResponseEndPoint.Address, discoveryResponse.AlpacaPort); // Create
if (!CachedEndpoints.Contains(alpacaApiEndpoint))
{
CachedEndpoints.Add(alpacaApiEndpoint);
LogMessage("FinderDiscoveryCallback", $"Received new Alpaca API endpoint: {alpacaApiEndpoint.ToString()} from broadcast endpoint: {alpacaBroadcastResponseEndPoint.ToString()}");
callbackFunctionDelegate?.Invoke(alpacaApiEndpoint, discoveryResponse); // Moved inside the loop so that the callback is only called once per IP address
}
else
{
LogMessage("FinderDiscoveryCallback", $"Ignoring duplicate Alpaca API endpoint: {alpacaApiEndpoint.ToString()} from broadcast endpoint: {alpacaBroadcastResponseEndPoint.ToString()}");
}
}
}
catch (ObjectDisposedException)
{
// Ignore these, they can occur after the Finder is disposed
}
catch (Exception ex)
{
LogMessage("FinderDiscoveryCallback", $"Exception: " + ex.ToString());
}
}
/// <summary>
/// Handler for device responses coming from the Finder
/// </summary>
/// <param name="responderIPEndPoint">Responder's IP address and port</param>
/// <param name="alpacaDiscoveryResponse">Class containing the information provided by the device in its response.</param>
private void BroadcastResponseEventHandler(IPEndPoint responderIPEndPoint, AlpacaDiscoveryResponse alpacaDiscoveryResponse)
{
try
{
LogMessage("BroadcastResponseEventHandler", $"FOUND Alpaca device at {responderIPEndPoint.Address}:{responderIPEndPoint.Port}"); // Log reception of the broadcast response
// Add the new device or ignore this duplicate if it already exists
lock (deviceListLockObject) // Make sure that the device list dictionary can't change while being read and that only one thread can update it at a time
{
if (!alpacaDeviceList.ContainsKey(responderIPEndPoint))
{
alpacaDeviceList.Add(responderIPEndPoint, new AlpacaDevice(responderIPEndPoint, Constants.TRYING_TO_CONTACT_MANAGEMENT_API_MESSAGE));
RaiseAnAlpacaDevicesChangedEvent(); // Device was added so set the changed flag
}
}
// Create a task to query this device's DNS name, if configured to do so
if (tryDnsNameResolution)
{
LogMessage("BroadcastResponseEventHandler", $"Creating task to retrieve DNS information for device {responderIPEndPoint.ToString()}:{responderIPEndPoint.Port}");
Thread dnsResolutionThread = new Thread(ResolveIpAddressToHostName);
dnsResolutionThread.IsBackground = true;
dnsResolutionThread.Start(responderIPEndPoint);
}
// Create a task to query this device's Alpaca management API
LogMessage("BroadcastResponseEventHandler", $"Creating thread to retrieve Alpaca management description for device {responderIPEndPoint.ToString()}:{responderIPEndPoint.Port}");
Thread descriptionThread = new Thread(GetAlpacaDeviceInformation);
descriptionThread.IsBackground = true;
descriptionThread.Start(responderIPEndPoint);
}
catch (Exception ex)
{
LogMessage("BroadcastResponseEventHandler", $"AddresssFound Exception: {ex.ToString()}");
}
}
