AFNetworking提交多部分表格不起作用？

Question

所以我正在测试AFNetworking的多部分表单提交。我设置了参数，为了测试NSData，我创建了一个UIImage并将该图像转换为NSData。您可以想象，我希望用户填写并上传图片，并让AFNetworking负责发送我的帖子请求。

不知道这不起作用？我收到了400 Bad Request错误。

注意：假设我的“路径”参数正确，“params”都设置正确。

    UIImage *myImage = [UIImage imageNamed:@"pekkle"];
    NSData *imageData = UIImagePNGRepresentation(myImage);

    // Setup path and parameters
    NSDictionary *params                    = @{
                                                @"description": description,
                                                @"title": title,
                                                @"userId": userId,
                                                @"collectionId": collectionId
                                                };

    // Setup manager and perform action
    AFHTTPRequestOperationManager *manager  = [AFHTTPRequestOperationManager manager];

    [manager POST:path parameters:params constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
        [formData appendPartWithFormData: imageData name:@"title"];
    } success:^(AFHTTPRequestOperation *operation, id responseObject){
      NSLog(@"success");
    } failure:^(AFHTTPRequestOperation *operation, NSError *error){
NSLog(@"failure %@", error);
    }];

这是错误

AFNetworkingOperationFailingURLResponseErrorKey=<NSHTTPURLResponse: 0x8a9feb0> { URL: http://myurl.com/file? } { status code: 400, headers {
    "Content-Encoding" = gzip;
    "Content-Length" = 624;
    "Content-Type" = "application/json; charset=utf-8";
    Vary = "Accept-Encoding";
} }, NSLocalizedDescription=Request failed: bad request (400)}