AFNetworking：从 CGI 脚本中检索大图像，跟踪服务器响应

Question

我确定我是颠倒过来的。我正在调用 CGI 脚本以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给用户一些反馈（我避免下载，因为从本地磁盘恢复图像需要更多时间）。

uploadProgress 跟踪发送到服务器的数据。有没有什么方法可以监控服务器的响应？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];

Answer 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 "Content-Length" 出现在响应 header 中时才会更新 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
}

AFNetworking：从 CGI 脚本中检索大图像，跟踪服务器响应

AFNetworking: retrieve large image from CGI script, tracking server response

objective-c

afnetworking

nsurlsession