ios – 问题从AFNetworking 1.3迁移到AFNetworking 2.0

我正在尝试将项目从AFNetworking 1.3迁移到AFNetworking 2.0.

在AFNetworking 1.3项目中,我有以下代码：

- (void) downloadJson:(id)sender
{

    NSURLrequest *request = [NSURLrequest requestWithURL:[NSURL URLWithString:@"http://myServer/api/call?param1=String1&param2=String2"]];

    AFJSONrequestOperation *operation = [AFJSONrequestOperation JSONrequestOperationWithrequest:request success:^(NSURLrequest *request,NShttpURLResponse *response,id JSON) {

        // handle success

    } failure:^(NSURLrequest *request,NSError *error,id JSON) {
        NSLog(@"%ld",(long)[response statusCode]);

        NSDictionary *data = JSON;
        NSString *errorMsg = [data objectForKey:@"descriptiveError@R_@R_197_11248@_8798@ge"];
        // handle failure

    }];

    [operation start];

}

当客户端发送格式不正确或参数错误的网址时,服务器会发回400错误并包含JSON,其中包含我在故障块中读取的“descriptiveError@R_@R_197_11248@_8798@ge”.我使用这个“descriptiveError@R_@R_197_11248@_8798@ge”来确定url的错误,并在适当的时候向用户发送消息.

AFNetworking 2.0项目的代码如下所示：

- (void)downloadJson:(id)sender
{
 NSURLrequest *request = [NSURLrequest requestWithURL:[NSURL URLWithString:@"http://myServer/api/call?param1=String1&param2=String2"]];

    AFhttprequestOperation *operation = [[AFhttprequestOperation alloc] initWithrequest:request];

    operation.responseserializer = [AFJSONResponseserializer serializer];

    [operation setCompletionBlockWithsuccess:^(AFhttprequestOperation *operation,id responSEObject) {

        // handle success

    } failure:^(AFhttprequestOperation *operation,NSError *error) {

        // any way to get the JSON on a 400 error?

    }];

    [operation start];
}

在AFNetworking 2.0项目中,我没有看到任何方法让JSON读取服务器发送的“descriptiveError@R_@R_197_11248@_8798@ge”.我可以在操作中从NShttpURLResponse获取响应头,但就我而言,也许我错过了一些东西.

有没有办法在失败块中获取JSON？如果没有,任何人都可以提出更好的方法吗？

在此先感谢您对此问题的任何帮助.