Why is didReceiveData function not working - ios

Question

I have a class which is used to get data from my server. The data returned from my server is in JSON. For some reason the didReceiveData won't run at all. I have placed NSLogs inside it to test it but it doesn't do anything?
Here is my code:
+(NSJSONSerialization *) getTask:(id)task_id{
NSString *post = [NSString stringWithFormat:#"&task_id=%#", task_id];
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:#"%lu",(unsigned long)[postData length]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
[request setURL:[NSURL URLWithString:[NSString stringWithFormat:#"http://my-server.com/"]]];
[request setHTTPMethod:#"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Current-Type"];
[request setHTTPBody:postData];
NSURLConnection *conn = [[NSURLConnection alloc]initWithRequest:request delegate:self];
if(conn){
NSLog(#"Testing");
}
return json;
}
// Log the response for debugging
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data {
NSLog(#"test");
NSString *jsonString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
json = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:nil];
}
// Declare any connection errors
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
NSLog(#"Error: %#", error);
}
Thanks,
Peter

Answer 1

getTask: is a class method, which means the self is the class. Therefore the delegate methods must also be class methods.
But note that you cannot return the received JSON from the getTask: method, because NSURLConnection works asynchronously.

Answer 2

You need to start the connection. Try using the initWithRequest:delegate:startImmediately: method:
NSURLConnection *conn = [[NSURLConnection alloc]initWithRequest:request delegate:self startImmediately:YES];
or, just call the start method:
if(conn){
[conn start];
}