Ios8 如何在AFNetworking 2.0中通过身份验证实现图像下载？

我有以下在AFNetworking 1.0中使用的图像下载功能。这是我为AF1.0实现HTTPClient的一部分

- (void)downloadImageWithCompletionBlock:(void (^)(UIImage *downloadedImage))completionBlock identifier:(NSString *)identifier {
NSString* urlString = identifier;

AFImageRequestOperation* operation = [AFImageRequestOperation imageRequestOperationWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:urlString]] imageProcessingBlock:nil
                                                                                       success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image)
                                      {
                                          //LogInfo(@"SUCCESS GETTING PHOTO: %@", response);
                                          completionBlock(image);
                                      }
                                                                                       failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {

                                                                                           LogInfo(@"ERROR GETTING PHOTO IN downloadImageWithCompletionBlock.");

                                                                                       }];
[operation setAuthenticationChallengeBlock:^(NSURLConnection *connection, NSURLAuthenticationChallenge *challenge) {
    NSURLCredential *newCredential = [NSURLCredential credentialWithUser:self.strSPUser password:self.strSPPW persistence:NSURLCredentialPersistenceForSession];
    [challenge.sender useCredential:newCredential forAuthenticationChallenge:challenge];
}];
[self enqueueHTTPRequestOperation:operation];
}

对于我为AFNetworking 1.0编写的HTTPClient自定义代码，我没有找到一个到AFNetworking 2.0的简单转换/升级。正如您在函数中所看到的，我正在向我的restful Web服务传递一个凭证以下载映像

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如何在AFNetworking 2.0中实现上述图像下载功能？

这与AFNetworking 2中的功能基本相同

AFHTTPRequestOperation

既有

credential

属性，又有

setWillSendRequestForAuthenticationChallengeBlock:

方法。

您确实需要我复制粘贴您的代码示例，并将

setAuthenticationChallengeBlock

替换为

setWillSendRequestForAuthenticationChallengeBlock

？这是相同的代码。