objective-c - iOS 似乎绕过了基本的服务器身份验证

Question

我正在尝试让我的 iOS 应用程序使用基本身份验证从我的本地 apache 服务器访问文件。在浏览器中一切正常，我必须输入我的用户名和密码才能访问受限文件夹中的图像。然而，在应用程序中发生了一些奇怪的事情。

我创建了一个 NSURLConnection 到服务器(一切正常)，第一次我的请求是委托(delegate)方法 - (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge 被调用。出于测试目的，我用一个空的 NSURLCredential 响应，显然连接失败了。但是，当我再次发出请求时，不会调用委托(delegate)方法，并且会以某种方式下载并显示图像而无需任何身份验证。我真的很困惑这是怎么回事!

部分代码如下:

- (IBAction)loginPressed
{
    self.username = self.usernameField.text;
    self.password = self.passwordField.text;
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://192.168.0.2/secret/favicon.ico"]];
    self.connection = [NSURLConnection connectionWithRequest:request delegate:self];
}


- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)data
{
    [self.data appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    self.imageView.image = [UIImage imageWithData:self.data];
    self.errorLabel.text = @"";
}

- (void)connection:(NSURLConnection *)connection willSendRequestForAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
    if ([challenge previousFailureCount] == 0) {
        NSURLCredential *newCredential = [NSURLCredential credentialWithUser:self.username password:self.password persistence:NSURLCredentialPersistenceNone];
        [challenge.sender useCredential:newCredential forAuthenticationChallenge:challenge];
    } else {
        [challenge.sender cancelAuthenticationChallenge:challenge];
        self.errorLabel.text = @"Invalid Username and/or Password";
        self.imageView.image = [UIImage imageWithData:[[NSData alloc] init]];
    }
}

Answer 1

您应该使用不同的委托(delegate)回调，connection:didReceiveAuthenticationChallenge:。

- (void) connection:(NSURLConnection *)connection 
    didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge {

    if ([challenge previousFailureCount] > 0) {
        // Do something, like prompt for credentials or cancel the connection
    } else {
        NSURLCredential *creds = [NSURLCredential 
                          credentialWithUser:@"someUser" 
                                    password:@"somePassword"
                                 persistence:NSURLCredentialPersistenceForSession];

        [[challenge sender]  useCredential:creds forAuthenticationChallenge:challenge];
    }
}