Wait before returning value iPhone

Question

I found some classes on the internet to establish a tcp connection. The link is in here . I want to customize a class and so far I am able to establish a connection send data and receive data which is great. Once I have created and imported the classes used by the first link that I provided I am able to establish a connection using the following method:

-(void) connectToServerUsingCFStream:(NSString *) urlStr portNo: (uint) portNo {

    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];    

    }
}

Since I am going to use this class a lot on my application I am creating my own class and I want to create a -(BOOL) connect{} method. I want to return yes is the connection is establish and no otherwise. The problem is that the way I am able to tell if I establish a connection is by creating a connection attempting to send data and then on the server side I have created a method that whenever I receive that I send a string back. If in the next 2 seconds I receive data I know that the connection was establish.

so in my connection method I want to wait 2 seconds and then return a value depending if the BOOL variable didReciveData = YES.

Answer 1

Since you use a NSOutputStream a better approach could be to check the return value of [oStream write:] : if it returns -1 no data has been sent, so there's no connection.

However, if you want to wait two seconds you can use NSTimer to create a timeout. If you receive a response before the timer fires you can invalidate the timer, otherwise the timer will call the related method that will notify the end of the two seconds.

Answer 2

You could try pausing the main run loop.

- (void)test
{
    NSLog(@"Test starting.");

    BOOL wasSuccessful = [self connect];
    NSLog(@"Success: %d", wasSuccessful);
}

- (BOOL)connect
{
    // try to connect here, make sure to get a callback on success/failure

    // fake callback
    [self performSelector:@selector(callback:) withObject:[NSNumber numberWithBool:NO] afterDelay:2.0];

    // wait for callback
    CFRunLoopRun();
    return self.success;
}

- (void)callback:(NSNumber *)successful
{
    self.success = [successful boolValue];

    CFRunLoopStop(CFRunLoopGetCurrent()); // now we want -connect to return!
}