Question

NEW SIMPLER VERSION OF PROBLEM:

I’m trying to connect to and communicate with a Bonjour device using an Objective-C client and I’m having trouble resolving the service (server). Originally I tried to do a more complicated example, but I found the basic socket connection even with port/ip specified wasn’t working.

I have the most barebones possible code using the cocoaAsyncSocket library:

AsyncSocket *xxx = [[[AsyncSocket alloc] initWithDelegate:self] autorelease];
NSError **err;
[xxx connectToHost: @"localhost" onPort: 5000 error: err];
NSLog(@"err=%@",err);

And here’s the server I’m trying to connect to (Python script):

# TCP server with bonjour broadcast!    
import select
import sys
import pybonjour
import socket
from time import sleep

#name    = sys.argv[1]
#regtype = sys.argv[2]
#port    = int(sys.argv[3])

# Bonjour service parameters
name = "TEST"
regtype = "_xxx._tcp."
port = 5000
# Tcp socket stuff
server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(("", port))
server_socket.listen(5)


def register_callback(sdRef, flags, errorCode, name, regtype, domain):
    if errorCode == pybonjour.kDNSServiceErr_NoError:
        print 'Registered service:'
        print '  name    =', name
        print '  regtype =', regtype
        print '  domain  =', domain

sdRef = pybonjour.DNSServiceRegister(name = name,
                                     regtype = regtype,
                                     port = port,
                                     callBack = register_callback)


# register bonjour service
print "Registering Bonjour service"
ready = select.select([sdRef], [], [])
print "ready=",ready
if sdRef in ready[0]:
    pybonjour.DNSServiceProcessResult(sdRef)

def configLoop():
    data = "Entering configuration mode"
    client_socket.send (data)
    data = "1) Network SSID: "
    client_socket.send (data)
    ssid = client_socket.recv(512)
    print "Network SSID:",ssid
    data = "2) Login: "
    client_socket.send (data)
    login = client_socket.recv(512)
    print "Login:",login
    data = "3) Password: "
    client_socket.send (data)
    passw = client_socket.recv(512)
    print "Password:",passw
    data = "Restarting server and attempting to connect to "+ssid
    client_socket.send (data)
    sleep(1)
    sys.exit(0)



print "TCPServer Waiting for client on port",port
try:
    while 1:

        client_socket, address = server_socket.accept()
        print "I got a connection from ", address

        data = "connection!"
        client_socket.send (data)

        while 1:
            data = client_socket.recv(512)
            if ( data == 'q' or data == 'Q'):
                client_socket.close()
                break;
            elif (data == 'C' or data == 'config'): # Enter configuration mode
                configLoop();
            else:
                print "RECIEVED:" , data

finally:
    sdRef.close()

The server never sees an incoming connection. On the client side, the error var has the value or something- nothing what I’d expect. Help please?

OLD (more complicated version, uses the same server):

My debug output basically says the service is resolved… and then I get a socket disconnect immediately after. Meanwhile my server sits there and hasn’t seen incoming connections.

I’ve walked through with the debugger when I get the initial connection and print out the name of the service- and then it hangs until I press continue and then I get a socket disconnect immediately after???

I’m very new to Objective-C and event driven programming, so perhaps I’m handling something wrong? I appreciate any advice!

Client (Debugger) output:

Running…
2011-05-10 14:10:26.822 Client[34709:a0f] TEST
2011-05-10 14:10:26.850 Client[34709:a0f] Socket disconnected
2011-05-10 14:10:29.724 Client[34709:a0f] Could not resolve: {
    NSNetServicesErrorCode = -72003;
    NSNetServicesErrorDomain = 10;
} 

Server output:

Registering Bonjour service
ready= ([<DNSServiceRef object at 0x100583290>], [], [])
Registered service:
  name    = TEST
  regtype = _xxx._tcp.
  domain  = local.
TCPServer Waiting for client on port 5000

The client code (ClientController.m, basically lifted from http://www.macresearch.org/cocoa-scientists-part-xxix-message):

#import "ClientController.h"
#import "AsyncSocket.h"


@interface ClientController ()

@property (readwrite, retain) NSNetServiceBrowser *browser;
@property (readwrite, retain) NSMutableArray *services;
@property (readwrite, assign) BOOL isConnected;
@property (readwrite, retain) NSNetService *connectedService;
@property (readwrite, retain) MTMessageBroker *messageBroker;

@end


@implementation ClientController

@synthesize browser;
@synthesize services;
@synthesize isConnected;
@synthesize connectedService;
@synthesize socket;
@synthesize messageBroker;

-(void)awakeFromNib {
    services = [NSMutableArray new];
    self.browser = [[NSNetServiceBrowser new] autorelease];
    self.browser.delegate = self;
    self.isConnected = NO;
}

-(void)dealloc {
    self.connectedService = nil;
    self.browser = nil;
    self.socket = nil;
    self.messageBroker = nil;
    [services release];
    [super dealloc];
}

-(IBAction)search:(id)sender {
    [self.browser searchForServicesOfType:@"_xxx._tcp." inDomain:@""];
}

-(IBAction)connect:(id)sender {
    NSNetService *remoteService = servicesController.selectedObjects.lastObject;
    remoteService.delegate = self;
    [remoteService resolveWithTimeout:30];
    NSLog(@"%@",remoteService.name);
}

-(IBAction)send:(id)sender {
    NSData *data = [textView.string dataUsingEncoding:NSUTF8StringEncoding];
    NSLog(textView.string);
    // Use socket to send raw text data once connected
}

#pragma mark AsyncSocket Delegate Methods
-(void)onSocketDidDisconnect:(AsyncSocket *)sock {
    NSLog(@"Socket disconnected");
}

-(BOOL)onSocketWillConnect:(AsyncSocket *)sock {
    if ( messageBroker == nil ) {
        [sock retain];
        return YES;
    }
    return NO;
}

-(void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port {      
    //MTMessageBroker *newBroker = [[[MTMessageBroker alloc] initWithAsyncSocket:socket] autorelease];
    //[sock release];
    //newBroker.delegate = self;
    //self.messageBroker = newBroker;
    self.isConnected = YES;
}

#pragma mark Net Service Browser Delegate Methods
-(void)netServiceBrowser:(NSNetServiceBrowser *)aBrowser didFindService:(NSNetService *)aService moreComing:(BOOL)more {
    [servicesController addObject:aService];
}

-(void)netServiceBrowser:(NSNetServiceBrowser *)aBrowser didRemoveService:(NSNetService *)aService moreComing:(BOOL)more {
    [servicesController removeObject:aService];
    if ( aService == self.connectedService ) self.isConnected = NO;
}

-(void)netServiceDidResolveAddress:(NSNetService *)service {
    NSError *error;
    self.connectedService = service;
    self.socket = [[[AsyncSocket alloc] initWithDelegate:self] autorelease];
    [self.socket connectToAddress:service.addresses.lastObject error:&error];
}

-(void)netService:(NSNetService *)service didNotResolve:(NSDictionary *)errorDict {
    NSLog(@"Could not resolve: %@", errorDict);
}

@end

Answer 1

I am having the same issue. It seems the problem is that a connection is already in place : “Attempting to connect while connected or accepting connections. Disconnect first”. Unfortunately i haven’t been able to resolve it yet. Any idea ? It might a delay or ordering process problem.

EDIT :
Actually, changing connectToAddress to ConnectToHost made it for me ! 🙂