cocoa - NSURLConnection 的 didCancelAuthenticationChallenge 委托(delegate)方法从未被调用

Question

为什么 NSURLConnection 的 didCancelAuthenticationChallenge 委托(delegate)方法永远不会被调用，即使在手动取消身份验证质询之后(实际上按预期被取消)？

我在下面粘贴了一些相关代码，请记住，除了 - (void)connection:(NSURLConnection *)connection didCancelAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge 之外，所有其他委托(delegate)方法均按照假定进行调用

感谢您的帮助。//迭戈

...
NSURLConnection *serviceConnection = [NSURLConnection connectionWithRequest:serviceRequest delegate:self];
...
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
    if ([challenge previousFailureCount]) {
        NSLog(@"Invalid credentials... Cancelling.");
        [[challenge sender] cancelAuthenticationChallenge:challenge];
            // AT THIS POINT cancelAuthenticationChallenge HAS BEEN CALLED, YET, DELEGATE METHOD IS NOT CALLED.
    } else {
        if ([ud stringForKey:@"username"] && [ud stringForKey:@"password"]) {
            NSLog(@"Service is trying to login with locally stored user and password from NSUserDefaults");
            NSURLCredential *credential = [NSURLCredential credentialWithUser:[ud stringForKey:@"username"]
                                                                     password:[ud stringForKey:@"password"]
                                                                  persistence:NSURLCredentialPersistenceForSession];
            [[challenge sender]useCredential:credential forAuthenticationChallenge:challenge];
        } else {
            [delegate STServiceNeedsLoginInfo:self];
        }
    }
}




- (void)connection:(NSURLConnection *)connection didCancelAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {
    NSLog(@"Failed login with status code: %d", [(NSHTTPURLResponse*)[challenge failureResponse]statusCode]);
    // THIS METHOD IS NEVER CALLED. WHY ?
}

Answer 1

我相信如果连接取消身份验证，则提供委托(delegate)方法，而不是您。例如如果您响应挑战的时间过长，理论上连接可能会取消身份验证。