通过HttpClient发送大文件

我需要通过HTTP协议上传大文件(约200MB)。我希望避免将文件加载到内存中,并希望直接发送它们。

多亏了这个 article 我能做到 HttpWebRequest .

HttpWebRequest requestToServer = (HttpWebRequest)WebRequest.Create("....");

requestToServer.AllowWriteStreamBuffering = false;
requestToServer.Method = WebRequestMethods.Http.Post;
requestToServer.ContentType = "multipart/form-data; boundary=" + boundaryString;
requestToServer.KeepAlive = false;
requestToServer.ContentLength = ......;

using (Stream stream = requestToServer.GetRequestStream())
{
    // write boundary string, Content-Disposition etc.
    // copy file to stream
    using (var fileStream = new FileStream("...", FileMode.Open, FileAccess.Read))
    {
        fileStream.CopyTo(stream);
    }

    // add some other file(s)
}

但是,我想通过 HttpClient . 我发现 article 其中描述了 HttpCompletionOption.ResponseHeadersRead 我尝试过这样的方法,但不幸的是,它不起作用。

WebRequestHandler handler = new WebRequestHandler();

using (var httpClient = new HttpClient(handler))
{
    httpClient.DefaultRequestHeaders.Add("ContentType", "multipart/form-data; boundary=" + boundaryString);
    httpClient.DefaultRequestHeaders.Add("Connection", "close");

    var httpRequest = new HttpRequestMessage(HttpMethod.Post, "....");

    using (HttpResponseMessage responseMessage = await httpClient.SendAsync(httpRequest, HttpCompletionOption.ResponseHeadersRead))
    {
        using (Stream stream = await responseMessage.Content.ReadAsStreamAsync())
        {
            // here I wanted to write content to the stream, but the stream is available only for reading
        }
    }
}

也许我忽略或错过了什么。。。

更新

除此之外,使用 StreamContent 具有适当的标题:

• Content-Disposition
• Content-Type