HttpClient和PushStreamContent

Question

我将PushStreamContent与我的REST API(ASP.NET Web API)一起使用并且效果很好.HttpClient可以请求一个ressource并在服务器处理完整请求之前获取HTTP响应(服务器仍然写入推送流).

作为HttpClient,你必须做一件小事:使用HttpCompletionOption.ResponseHeadersRead.

现在我的问题:是否有可能以另一种方式？从HttpClient - >通过push-stream将数据上传到web api？

我实现了如下所示,但是web api在客户端关闭流之前不会收到请求.

         var asyncStream = new AsyncStream(fs);
         PushStreamContent streamContent = new PushStreamContent(asyncStream.WriteToStream);
         content.Add(streamContent);

         HttpResponseMessage response = await c.SendAsync(new HttpRequestMessage(new HttpMethod("POST"), "http://localhost/...") { Content = content }, HttpCompletionOption.ResponseHeadersRead);

         response.EnsureSuccessStatusCode();

AsyncStream是我的代表类:

public async void WriteToStream(Stream outputStream, HttpContent content, TransportContext context)

这对于Push-Stream是必要的.

这有可能吗？HttpClient不会将请求发送到Web api,直到最后一个字节写入流...

我需要做什么？问题出在客户端还是在服务器/ asp.net web api端？

编辑:这是WriteToStream的实现(但我不使用磁盘中的文件,使用内存流'myMemoryStream'(在构造函数中传递):

public void WriteToStream(Stream outputStream, HttpContent content, TransportContext context)
{
    try
    {
        var buffer = new byte[4096];

        using (var stream = myMemoryStream)
        {
            var bytesRead = 1;

            while (bytesRead > 0)
            {
                bytesRead = video.Read(buffer, 0, buffer.Length);
                outputStream.Write(buffer, 0, bytesRead);
            }
        }
    }
    catch (HttpException ex)
    {
        return;
    }
    finally
    {
        outputStream.Close();
    }
}

也许我必须做一些事情:HttpContent内容,TransportContext上下文？

Answer 1

我找到了解决问题的方法:

我想设置:httpWebRequest.AllowReadStreamBuffering = false;

HttpClient 4.0默认执行缓冲,您无法访问属性AllowReadStreamBuffering,因此您必须直接使用HttpWebRequest.(或者你可以使用HttpClinet 4.5,默认行为'流''):http://www.strathweb.com/2012/09/dealing-with-large-files-in-asp-net-web-api / 6.使用HttpClient)

第二个问题是fiddler:Fiddler目前只支持响应流而不是请求(Fiddler使HttpWebRequest/HttpClient行为意外)

对我有用的解决方案:

HttpWebRequest httpWebRequest = HttpWebRequest.Create(...)
httpWebRequest.Method = "POST";
         httpWebRequest.Headers["Authorization"] = "Basic " + ...;
         httpWebRequest.PreAuthenticate = true;
         httpWebRequest.AllowWriteStreamBuffering = false;
         httpWebRequest.AllowReadStreamBuffering = false;
         httpWebRequest.ContentType = "application/octet-stream";
         Stream st = httpWebRequest.GetRequestStream();
st.Write(b, 0, b.Length);
st.Write(b, 0, b.Length);
//...
         Task<WebResponse> response = httpWebRequest.GetResponseAsync();

         var x = response.Result;
         Stream resultStream = x.GetResponseStream();
//... read result-stream ...