AFNetworking：从 CGI 脚本中检索大图像，跟踪服务器响应

Posted 2023-02-23

【中文标题】AFNetworking：从 CGI 脚本中检索大图像，跟踪服务器响应

【英文标题】：AFNetworking: retrieve large image from CGI script, tracking server response

【发布时间】：2016-10-11 03:31:23

【问题描述】：

我确定我是颠倒过来的。我正在调用 CGI 脚本从服务器上的私有目录中获取大图像。在下面的代码中，我从服务器响应中检索图像。

一切正常，但我想监控响应进度以向用户提供一些反馈（我正在避免下载，因为从本地磁盘恢复图像需要额外的时间）。

uploadProgress 跟踪发送到服务器的数据。有什么方法可以监控服务器的响应吗？看起来 responseObject 只能在完成处理程序中访问。

NSMutableURLRequest *request = [[AFHTTPRequestSerializer serializer] multipartFormRequestWithMethod:@"POST"      URLString:@"http://www.myurl.com/redirect.html" parameters:nil constructingBodyWithBlock:^(id<AFMultipartFormData> formData) 
        NSLog(@"Calling server");

        [formData appendPartWithFormData:[user_id dataUsingEncoding:NSUTF8StringEncoding] name:@"user"];
        [formData appendPartWithFormData:[_imageURL dataUsingEncoding:NSUTF8StringEncoding] name:@"filename"];
     error:nil];

AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];

    manager.responseSerializer = [AFHTTPResponseSerializer serializer];

    NSURLSessionUploadTask *uploadTask;
    uploadTask = [manager uploadTaskWithStreamedRequest:request progress:^(NSProgress * _Nonnull uploadProgress) 

           dispatch_async(dispatch_get_main_queue(), ^
                          NSLog(@"SERVER UPLOAD FRACTION COMPLETED: %f", uploadProgress.fractionCompleted);
                      );

                   completionHandler:^(NSURLResponse * _Nonnull response, id  _Nullable responseObject, NSError * _Nullable error) 

                      NSLog(@"Error: %@", error);
                      NSLog(@"RESPONSE: %@", response);
                      NSLog(@"responseObject: %@", responseObject);

                       if (error) 
                           NSLog(@"Error: %@", error); 
                        else 

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),^

                      UIImage *image = [UIImage imageWithData:responseObject];

                               dispatch_sync(dispatch_get_main_queue(), ^

                                   [myImageView setImage:image];

                               );
                           );
                       

                  ];
    [uploadTask resume];

【参考方案1】：

事实证明，AFNetworking 有一个很好的数据任务方法，可以监控上传和下载任务的进度：

dataTaskWithRequest:uploadProgress:downloadProgress:completionHandler:

唯一需要注意的是，仅当响应标头中存在“Content-Length”时才会更新 downloadProgress 块。

NSMutableURLRequest *request = [[AFHTTPRequestSerializer serializer] multipartFormRequestWithMethod:@"POST" URLString:urlString parameters:nil constructingBodyWithBlock:^(id<AFMultipartFormData> formData) 
        [formData appendPartWithFormData:[imageURL dataUsingEncoding:NSUTF8StringEncoding] name:@"filename"];
     error:nil];

AFURLSessionManager *manager = [[AFURLSessionManager alloc] initWithSessionConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
    manager.responseSerializer = [AFHTTPResponseSerializer serializer];

NSURLSessionDataTask *uploadTask = [manager dataTaskWithRequest:request uploadProgress:^(NSProgress * _Nonnull uploadProgress) 
        dispatch_async(dispatch_get_main_queue(), ^
            NSLog(@"SERVER UPLOAD FRACTION COMPLETED: %f", uploadProgress.fractionCompleted);
        );

     downloadProgress:^(NSProgress * _Nonnull downloadProgress) 

        dispatch_async(dispatch_get_main_queue(), ^
            NSLog(@"SERVER DOWNLOAD FRACTION COMPLETED: %f", downloadProgress.fractionCompleted);
        );

     completionHandler:^(NSURLResponse * _Nonnull response, id  _Nullable responseObject, NSError * _Nullable error) 
       // retrieve the image from the responseObject here