NSFileHandle acceptConnectionInBackgroundAndNotify example ios

acceptConnectionInBackgroundAndNotify

Accepts a socket connection (for stream-type sockets only) in the background and creates a file handle for the “near” (client) end of the communications channel.

- (void)acceptConnectionInBackgroundAndNotify

Discussion of [NSFileHandle acceptConnectionInBackgroundAndNotify]

This method asynchronously creates a file handle for the other end of the socket connection and returns that object by posting a NSFileHandleConnectionAcceptedNotification notification in the current thread. The notification includes a userInfo dictionary with the created NSFileHandle object, which is accessible using theNSFileHandleNotificationFileHandleItem key.

You must call this method from a thread that has an active run loop.

Special Considerations of [NSFileHandle acceptConnectionInBackgroundAndNotify]

The receiver must be created by an initWithFileDescriptor: message that takes as an argument a stream-type socket created by the appropriate system routine, and that is being listened on. In other words, you must bind() the socket, and ensure that the socket has a connection backlog defined by listen().

The object that will write data to the returned file handle must add itself as an observer ofNSFileHandleConnectionAcceptedNotification.

Note that this method does not continue to listen for connection requests after it postsNSFileHandleConnectionAcceptedNotification. If you want to keep getting notified, you need to call acceptConnectionInBackgroundAndNotify again in your observer method.

Example of [NSFileHandle acceptConnectionInBackgroundAndNotify]

-(void)createSocket 

{

    // create socket and wait for events to come in

    NSSocketPort* serverSock = [[NSSocketPort alloc] initWithTCPPort: 1234];

    socketHandle = [[NSFileHandle alloc] initWithFileDescriptor: [serverSock socket]

                                                 closeOnDealloc: NO];

    [[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(newConnection:) 

                                                 name: NSFileHandleConnectionAcceptedNotification

                                               object: socketHandle];

    [socketHandle acceptConnectionInBackgroundAndNotify];

}

- (void)newConnection:(NSNotification*)notification

{

    NSLog(@"connection accepted");

    NSDictionary* userInfo = [notification userInfo];

    NSFileHandle* remoteFileHandle = [userInfo objectForKey:

                                      NSFileHandleNotificationFileHandleItem];

    if([[userInfo allKeys] containsObject:@"NSFileHandleError"]){

        NSNumber* errorNo = [userInfo objectForKey:@"NSFileHandleError"];

        if( errorNo ) {

            NSLog(@"NSFileHandle Error: %@", errorNo);

            return;

        }

    }

    [socketHandle acceptConnectionInBackgroundAndNotify];

    [[NSNotificationCenter defaultCenter] addObserver:self 

       selector: @selector(processSocketData:)

           name: NSFileHandleReadCompletionNotification

         object: remoteFileHandle];

    // Send a message to the client, acknowledging that the connection was accepted

    [remoteFileHandle writeData: [@"OK" dataUsingEncoding: NSASCIIStringEncoding]];

    [remoteFileHandle readInBackgroundAndNotify];

}