ios - セマフォを使用して非同期呼び出しから値を返す

Question

NSURLSessionネットワーク通話を行うために使用する必要があります。特定の事柄に基づいて、応答を受け取った後、NSErrorオブジェクトを返す必要があります。

セマフォを使用して、非同期呼び出しを同期的に動作させています。問題は、エラーが呼び出し内で適切に設定されることですが、セマフォが終了するとすぐに (

dispatch_semaphore_wait(セマフォ, DISPATCH_TIME_FOREVER);

)、 はerrゼロになります。

助けてください

コード：

-(NSError*)loginWithEmail:(NSString*)email Password:(NSString*)password
{
    NSError __block *err = NULL;

        // preparing the URL of login
        NSURL *Url              =       [NSURL URLWithString:urlString];

        NSData *PostData        =       [Post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

        // preparing the request object
        NSMutableURLRequest *Request = [[NSMutableURLRequest alloc] init];
        [Request setURL:Url];
        [Request setHTTPMethod:@"POST"];
        [Request setValue:postLength forHTTPHeaderField:@"Content-Length"];
        [Request setHTTPBody:PostData];

        NSMutableDictionary __block *parsedData = NULL; // holds the data after it is parsed

        dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

        NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
        config.TLSMinimumSupportedProtocol = kTLSProtocol11;

        NSURLSession *session = [NSURLSession sessionWithConfiguration:config delegate:nil delegateQueue:nil];

        NSURLSessionDataTask *task = [session dataTaskWithRequest:Request completionHandler:^(NSData *data, NSURLResponse *response1, NSError *err){
                if(!data)
                {
                    err = [NSError errorWithDomain:@"Connection Timeout" code:200 userInfo:nil];
                }
                else
                {
                    NSString *formattedData = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

                    NSLog(@"%@", formattedData);

                    if([formattedData rangeOfString:@"<!DOCTYPE"].location != NSNotFound || [formattedData rangeOfString:@"<html"].location != NSNotFound)
                    {
                        loginSuccessful = NO;
                        //*errorr = [NSError errorWithDomain:@"Server Issue" code:201 userInfo:nil];
                        err = [NSError errorWithDomain:@"Server Issue" code:201 userInfo:nil];
                    }
                    else
                    {
                        parsedData = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&err];
                        NSMutableDictionary *dict = [parsedData objectForKey:@"User"];

                        loginSuccessful = YES;
                }
            dispatch_semaphore_signal(semaphore);
        }];
        [task resume];

        // but have the thread wait until the task is done

        dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);

    return err;
}