gistfile1.c

- (void)postPath:(NSString *)path
      parameters:(NSDictionary *)parameters
         success:(void (^)(AFHTTPRequestOperation *operation, id responseObject))success
         failure:(void (^)(AFHTTPRequestOperation *operation, NSError *error))failure {
    
	NSURLRequest* request = [self requestWithMethod:@"POST" path:path parameters:parameters];
	AFHTTPRequestOperation* operation = [self HTTPRequestOperationWithRequest:request success:success failure:failure];
    
    void (^timeout)(void) = ^ {
        [operation cancel];
        
        // construct "request time out" error
        NSError* error = [NSError errorWithDomain:NSURLErrorDomain
                                             code:-1001
                                         userInfo:[NSDictionary dictionaryWithObjectsAndKeys:@"The request timed out.",
                                                   NSLocalizedDescriptionKey, nil]];
        
        dispatch_async(dispatch_get_main_queue(), ^{
            failure(operation, error);
        });
    };

    if (SYSTEM_VERSION_LESS_THAN(@"6.0")) {
        [NSTimer scheduledTimerWithTimeInterval:_interval target:self selector:@selector(timeOut:) userInfo:[timeout copy] repeats:NO];
    }
    
    [self enqueueHTTPRequestOperation:operation];
}

// called when a timeout occurs
- (void)timeOut:(NSTimer *)timer {
    void (^timeout)(void) = [timer userInfo];
    timeout();
}