我有以下代码：

NSMutableURLRequest *apiRequest =
[self multipartFormRequestWithMethod:@"POST"
                                path: pathstr
                          parameters: params
           constructingBodyWithBlock: ^(id <AFMultipartFormData>formData)
           {
               //TODO: attach file if needed
           }];



AFJSONRequestOperation* operation = [[AFJSONRequestOperation alloc] initWithRequest: apiRequest];
[operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation,id responSEObject) {
    //success!
    completionBlock(responSEObject);
} failure:^(AFHTTPRequestOperation *operation,NSError *error) {
    //failure :(

    NSLog(@"%@",error);
    completionBlock([NSDictionary dictionaryWithObject:[error localizedDescription] forKey:@"error"]);
}];

[operation start];