NSURLConnection hangs for server which is not available - iphone

Question

I'm using NSURLConnection initWithRequest to get some data from a server. This works fine when the server is available. However when the server is not available my app hangs and becomes totally unresponsive for at least 40-50 seconds. I've tried using a timeoutInterval, as well as a timer to cancel the request. However my app still hangs.
Whilst my app is hanging, none of the NSURLConnectionDelegate methods have been called. The onTimeExpire gets called but doesn't do anything. Once the app becomes responsive again (50 seconds later...), the NSURLConnectionDelegate delegate methods get called and all is good...
The server is a local server with ip 192.168.x.x which will pull data down to the app only when the server (and csv) file is available.
I thought of doing a simple check before firing off the NSURLConnection to see if the server is online first. But can't seem to work out how to do this? Any ideas?
-(id) loadCSVByURL:(NSString *)urlString
{
// Create the request.
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:urlString] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:30.0f];
self.timer = [NSTimer scheduledTimerWithTimeInterval:20 //for testing..
target:self
selector:#selector(onTimeExpired)
userInfo:nil
repeats:NO];
(void)[self.connection initWithRequest:request delegate:self];
//THE APP HANGS HERE!!!
return self;
}
-(void)onTimeExpired
{
NSLog(#"cancelling connection now!");
[self.connection cancel];
}

Answer 1

You are setting a timeout of 20 but a connection timeout of 30. That means that even if your setup were correct, the timer would fire before the unsuccessful connection fails.
More importantly, you are sending an init message to your connection object twice. This does not make sense.
You need instead to create the connection with the request and then start it.
self.connection = [[NSURLConnection alloc]
initWithRequest:request delegate:self];
[connection start];
You then react to the failure of the connection in the NSURLConnectionDelegate callback connection:didFailWithError: which should fire after the connection times out.