Objective C Socket Server does not receive Java Socket Client Messages

Question

I created server in Objective C, using CocoaAsyncTask , it works fine if I connect from telnet both localhost and on same network.

Now I have a client in Java, that works fine with another Java server and I cannot get to communicate; no messages are received on sever side.

For reference, here is the Java Client code:

    public class Client {
   public static void main(String[] args) {
       try {
           Socket socket = new Socket("192.168.0.106",4353);
           PrintWriter printWriter = new PrintWriter(socket.getOutputStream(),true);
           BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

           while (true) {
               System.out.println("Enter message: ");
               String msg = br.readLine();

               if (msg != null && !msg.equals("bye"))
               {
                   printWriter.println(msg);
               }
               else
               {
                   break;
               } } } catch (IOException e) {e.printStackTrace();} } }

And the server Objective C code:

    ...
    [newSocket readDataToData:[GCDAsyncSocket CRLFData] withTimeout:15.0 tag:0];
    ...

    (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag {
        dispatch_async(dispatch_get_main_queue(), ^{
            @autoreleasepool {
                DDLogInfo(@"data: %@", data);
                NSData *strData = [data subdataWithRange:NSMakeRange(0, [data length] - 2)];
                DDLogInfo(@"Info: %@", strData);
                NSString *msg = [[NSString alloc] initWithData:strData encoding:NSUTF8StringEncoding];
                DDLogInfo(@"Info: %@", msg);

We've tried appending \\n and \\r at the end, but no success.

What could cause this miss-communication?

Answer 1

The problem was on the server side, by receiving the data from socket using readDataToData , instead of readDataWithTimeout .

Most probable, the problem is in line ending, so the library does not process it as a line, thus not calling the method for the next data.