/// <summary>
/// Searches for an available devices of specified type.
/// </summary>
/// <param name="searchTarget">
/// The type of the devices to search for.
/// </param>
/// <param name="timeForResponse">
/// The time (in seconds) of a search.
/// </param>
/// <returns>
/// An observable collection which contains search results.
/// </returns>
public IObservable <SearchResponseMessage> Search(string searchTarget, int timeForResponse)
{
return(Observable.Create <SearchResponseMessage>(async observer =>
{
var searchSocket = new DatagramSocket();
// Handling responses from found devices
searchSocket.MessageReceived += async(sender, args) =>
{
var dataReader = args.GetDataReader();
dataReader.InputStreamOptions = InputStreamOptions.Partial;
if (dataReader.UnconsumedBufferLength == 0)
{
await dataReader.LoadAsync(1024);
}
var message = dataReader.ReadString(dataReader.UnconsumedBufferLength);
try
{
var response = SearchResponseMessage.Create(message);
observer.OnNext(response);
}
catch (ArgumentException ex)
{
logger.Instance().Warning(ex, "The received M-Search response has been ignored.", "Message".As(message));
}
};
await searchSocket.BindServiceNameAsync("0");
searchSocket.JoinMulticastGroup(this.multicastHost);
var request = MSearchRequestFormattedString.F(searchTarget, timeForResponse);
var buffer = Encoding.UTF8.GetBytes(request).AsBuffer();
// Sending the search request to a multicast group
var outputStream = await searchSocket.GetOutputStreamAsync(this.multicastHost, MulticastPort.ToString());
await outputStream.WriteAsync(buffer);
await outputStream.WriteAsync(buffer);
// Stop listening for a devices when timeout for responses is expired
Observable.Timer(TimeSpan.FromSeconds(timeForResponse)).Subscribe(s =>
{
observer.OnCompleted();
searchSocket.Dispose();
});
logger.Instance().Debug("M-Search request has been sent. [multicastHost={0}, searchTarget={1}]".F(multicastHost.DisplayName, searchTarget));
return searchSocket.Dispose;
}));
}
private static void HandleSearchResponseMessage(string message, IObserver <SearchResponseMessage> observer)
{
logger.Instance().Trace("Received search response message", "Message".As(message));
try
{
var responseMessage = SearchResponseMessage.Create(message);
observer.OnNext(responseMessage);
}
catch (ArgumentException ex)
{
logger.Instance().Warning(ex, "The received M-Search response has been ignored.", "Message".As(message));
}
}
