最近作成されたYouTubeチュートリアルに従って、非同期でWebアドレスに接続してみてください。応答に対してnullを再調整しますが、データ長が0より大きいです。nullと長さの両方のチェックを行う他のコードを見ましたが、スローせず、NSLogしただけです。
@implementation ViewController
-(void)fetchAddress:(NSString *)address  {
NSLog(@"Loading Address: %@", address);
[iOSRequest requestToPath:address onCompletion:^(NSString *result, NSError *error)  {
    dispatch_async(dispatch_get_main_queue(), ^{
        if (error)  {
            [self stopFetching:@"Failed to Fetch"];
            NSLog(@"%@", error);
        } else  {
            [self stopFetching:result];
            NSLog(@"Good fetch:  %@", result);
        }
        });
    }];
}
- (IBAction)fetch:(id)sender {
    [self startFetching];
    [self fetchAddress:self.addressField.text];
    NSLog(@"Address: %@", self.addressField.text);
}
-(void)startFetching  {
    NSLog(@"Fetching...");
    [self.addressField resignFirstResponder];
    [self.loading startAnimating];
    self.fetchButton.enabled = NO;
}
-(void)stopFetching:(NSString *)result  {
    NSLog(@"Done Fetching  %@", result);
    self.outputLabel.text = result;
    [self.loading stopAnimating];
    self.fetchButton.enabled = YES;
}
@implementation iOSRequest
    +(void)requestToPath:(NSString *)
        path onCompletion:(RequestCompletionHandler)complete  {
    NSOperationQueue *backgroundQueue = [[NSOperationQueue alloc] init];
    NSURLRequest *request = [[NSURLRequest alloc] initWithURL:[NSURL URLWithString:path]
        cachePolicy:NSURLCacheStorageAllowedInMemoryOnly
        timeoutInterval:10];
    NSLog(@"path:  %@  %@", path, request);
    [NSURLConnection sendAsynchronousRequest:request
        queue:backgroundQueue
        completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)  {
        NSString *result = [[NSString alloc] initWithData:
            data encoding:NSUTF8StringEncoding];
        if (complete)  {
           complete(result, error);
           NSLog(@"result:  %@ %lu %@", result, (unsigned long)[data length], error);
        }
    }];
}
リクエストはhttp://www.google.com>レスポンスはnullデータ長は13644
何が悪いのかわからない...何か提案はありますか?