Question

I press the button to connect to the server (TCP), but i don’t know whether it connected or not..
Here is that part of the code:

[self connectToServerUsingCFStream:msg portNo:50000];

    if(readStream && writeStream)
    {
        NSString *newText = [[NSString alloc] initWithFormat:@"Connected!! :)"]; 
        statusText.text = newText;
        [newText release];
        pingButton.hidden = NO;
    }
    else
    {
        NSString *newText = [[NSString alloc] initWithFormat:@"Connection unsuccessful :("]; 
        statusText.text = newText;
        [newText release];
    }

I always get the “Connected!! :)” even if the server is offline :s

Answer 1

The solution for people following the connection method:

CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, 
                                   (CFStringRef) urlStr, 
                                   portNo, 
                                   &readStream, 
                                   &writeStream);

if (readStream && writeStream) 
{
    CFReadStreamSetProperty(readStream, 
                            kCFStreamPropertyShouldCloseNativeSocket, 
                            kCFBooleanTrue);
    CFWriteStreamSetProperty(writeStream, 
                             kCFStreamPropertyShouldCloseNativeSocket, 
                             kCFBooleanTrue);

    iStream = (NSInputStream *)readStream;
    [iStream retain];
    [iStream setDelegate:self];
    [iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] 
                       forMode:NSDefaultRunLoopMode];
    [iStream open];

    oStream = (NSOutputStream *)writeStream;
    [oStream retain];
    [oStream setDelegate:self];
    [oStream scheduleInRunLoop:[NSRunLoop currentRunLoop] 
                       forMode:NSDefaultRunLoopMode];
    [oStream open];         
} 

is using the

-(void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent

like this:

-(void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent
{
NSString *io;
if (theStream == iStream) io = @">>";
else io = @"<<";

NSString *event;
switch (streamEvent)
{
    case NSStreamEventNone:
        event = @"NSStreamEventNone";
        statusText.text =  @"Can not connect to the host!";
        break;

    case NSStreamEventOpenCompleted:
        event = @"NSStreamEventOpenCompleted";
        pingButton.hidden = NO;
        statusText.text = @"Connected";
        break;

    case NSStreamEventHasBytesAvailable:
        event = @"NSStreamEventHasBytesAvailable";
        if (theStream == iStream)
        {
            //read data
            uint8_t buffer[1024];
            int len;
            while ([iStream hasBytesAvailable])
            {
                len = [iStream read:buffer maxLength:sizeof(buffer)];
                if (len > 0)
                {
                    NSString *output = [[NSString alloc] initWithBytes:buffer length:len encoding:NSASCIIStringEncoding];
                    NSData *theData = [[NSData alloc] initWithBytes:buffer length:len];
                    if (nil != output)
                    {
                        //do something with data
                    }
                }
            }
        }
        break;

    case NSStreamEventHasSpaceAvailable:
        event = @"NSStreamEventHasSpaceAvailable";
        if (theStream == oStream)
        {
            //send data
            uint8_t buffer[11] = "I send this";             
            int len;

            len = [oStream write:buffer maxLength:sizeof(buffer)];
            if (len > 0)
            {
                NSLog(@"Command send");
                [oStream close];
            }
        }

        break;

    case NSStreamEventErrorOccurred:
        event = @"NSStreamEventErrorOccurred";
        statusText.text = @"Can not connect to the host!";
        pingButton.hidden = YES;
        break;

    case NSStreamEventEndEncountered:
        event = @"NSStreamEventEndEncountered";
        statusText.text = @"Connection closed by the server.";
        pingButton.hidden = YES;
        [theStream close];
        [theStream removeFromRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        [theStream release];
        theStream = nil;
        break;

    default:
        event = @"** Unknown";
}

NSLog(@"%@ : %@", io, event);
}

(for all I know!) The credits go to deksa from this post (though i don’t know who was the creator, because i’ve seen this some times on the web, including here o SO). This code was slightly modified by me (pingButton, statusText), if you want the original one go to the link previously mentioned.

The Apple Developer Site has some info on this as well.

Like i’ve said, I had seen some stuff looking like this on the web, but now i understand that everything that happens after you connect is “automatic”; for instance, if the server is on hold with a read(), the case NSStreamEventHasSpaceAvailable: will be called automatically, and all the code in there will be run.

Now I consider this question answered.