HttpClient内容处置中的编码错误 [英] HttpClient wrong encoding in Content-Disposition

问题描述

我正在使用 HttpClient 发布图像，它对于带有拉丁名称的文件效果很好，但是一旦名称包含任何非ASCII字符，它将立即转换为问号序列.如果我创建一个html表单并使用浏览器发布该文件，则该文件名将以UTF8发送，并且目标服务器会完全接受它.

I am POST-ing an image with HttpClient and it works well for files with Latin names, but as soon as a name contains any non-ASCII characters it gets transformed to a sequence of question marks. If I create an html form and use a browser to post the file, the file name is sent in UTF8 and the target server perfectly accepts it.

using (var client = new HttpClient())
{
    var streamContent = new StreamContent(someImageFileStream);
    streamContent.Headers.Add(
        "Content-Disposition",
        "form-data; name=\"image\"; filename=\"Тест.jpg\"");

    var content = new MultipartFormDataContent();
    content.Add(streamContent);

    await client.PostAsync("http://localhost.fiddler/", content);
}

这将产生以下请求:

POST http://localhost/ HTTP/1.1
Content-Type: multipart/form-data; boundary="e6fe89be-e652-4fe3-8859-8c7a339c5550"
Host: localhost
Content-Length: 10556

--e6fe89be-e652-4fe3-8859-8c7a339c5550
Content-Disposition: form-data; name="image"; filename="????.jpg"

...here goes the contents of the file...

我了解 HttpClient 可以按照某些标准工作，但是无论如何，有什么解决方法吗?

I understand that HttpClient might work according to some standard, but anyway, is there any workaround?

更新:外部API不想接受 filename * =utf-8''Тест.jpg格式，它需要 filename ="Тест.jpg" .

UPDATE: The external API doesn't want to accept the format filename*=utf-8''Тест.jpg, it expects filename="Тест.jpg".

推荐答案

好的，我找到了一种方法来强制 MultipartFormDataContent 忘记古老的RFC，而改用UTF8.诀窍是使用反射来覆盖内部静态类 HttpRuleParser 中定义的 DefaultHttpEncoding .

OK, I've found a way to force MultipartFormDataContent to forget the ancient RFCs and use UTF8 instead. The trick is to use reflection to overwrite the DefaultHttpEncoding defined in the internal static class HttpRuleParser.

typeof(HttpClient)
  .Assembly
  .GetType("System.Net.Http.HttpRuleParser")
  .GetField("DefaultHttpEncoding", BindingFlags.Static | BindingFlags.NonPublic)
  .SetValue(null, System.Text.Encoding.UTF8);

不确定会导致哪些不良后果，但我想没有.

Not sure which bad consequences that might cause, but I suppose there are none.

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