NSURLSession delegate methods not called

问题:

I have created a very simple app to download a text file from my web server. I have this working perfectly with NSURLConnection, but am trying to migrate over to NSURLSession instead.

The issue I am having is that none of the delegate methods are being called.

My server is password protected so I need to use the basic http authentication to access the file, but when the didReceiveChallenge method is never called.

The line of code [getFileTask resume] seems to have no effect on anything.

My setup is as follows:

@interface ViewController : UIViewController <NSURLSessionDelegate, NSURLSessionDownloadDelegate, NSURLSessionTaskDelegate>
{
   NSURLSession *session;
}

The following method is called from viewDidLoad:

-(void)setUpTheNetworking
{
    NSString *fileURL = @"www.mywebsite.com/utility/file.txt";

    NSURLSessionConfiguration *sessionConfig = [NSURLSessionConfiguration defaultSessionConfiguration];
    sessionConfig.allowsCellularAccess = YES;
    sessionConfig.timeoutIntervalForRequest = 10;
    sessionConfig.timeoutIntervalForResource = 10;
    sessionConfig.HTTPMaximumConnectionsPerHost = 1;

    session = [NSURLSession sessionWithConfiguration:sessionConfig delegate:self delegateQueue:nil];

    NSURLSessionDownloadTask *getFileTask = [session downloadTaskWithURL:[NSURL URLWithString:fileURL]];

    [getFileTask resume];
}

The delegate methods I have implemented are:

-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didWriteData:(int64_t)bytesWritten totalBytesWritten:(int64_t)totalBytesWritten totalBytesExpectedToWrite:(int64_t)totalBytesExpectedToWrite
{
    NSLog(@"Here we go");
}

-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didResumeAtOffset:(int64_t)fileOffset expectedTotalBytes:(int64_t)expectedTotalBytes
{
    NSLog(@"Here we go");
}

-(void)URLSession:(NSURLSession *)session downloadTask:(NSURLSessionDownloadTask *)downloadTask didFinishDownloadingToURL:(NSURL *)location
{
    NSLog(@"Here we go");
}

- (void)URLSession:(NSURLSession *)session didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler
{
   if (challenge.previousFailureCount == 0)
   {
       NSURLCredentialPersistence persistence = NSURLCredentialPersistenceForSession;
       NSURLCredential *credential = [NSURLCredential credentialWithUser:user password:@password persistence:persistence];
       completionHandler(NSURLSessionAuthChallengeUseCredential, credential);
   }
   else
   {
       // handle the fact that the previous attempt failed
       NSLog(@"%s: challenge.error = %@", __FUNCTION__, challenge.error);
       completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil);
   }
}

 - (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task
   didReceiveChallenge:(NSURLAuthenticationChallenge *)challenge
   completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition disposition, NSURLCredential *credential))completionHandler
{
    {
        if (challenge.previousFailureCount == 0)
        {
             NSURLCredential *credential = [NSURLCredential  credentialWithUser:user password:password persistence:NSURLCredentialPersistenceForSession];
        completionHandler(NSURLSessionAuthChallengeUseCredential, credential);
        }
        else
        {
            NSLog(@"%s; challenge.error = %@", __FUNCTION__, challenge.error);
            completionHandler(NSURLSessionAuthChallengeCancelAuthenticationChallenge, nil);
        }

    }
}

Thanks!

回答1:

SOLVED!

The following line of code was the culprit:

 NSString *fileURL = @"www.mywebsite.com/utility/file.txt";

Turns out it needed http:// in there as well, so this one works

 NSString *fileURL = @"http://www.mywebsite.com/utility/file.txt";

It still seems weird to me that it just didn't work. I would have expected an error to popup.