.net - System.Net.Http.HttpClient 是否受到 HttpWebRequest.AllowWriteStreamBuffering 的影响？

Question

我一直在尝试使用 System.Net.Http.HttpClient发布一个更大的文件(+1GB)，但它抛出一个 SystemOutOfMemory异常(exception):

at System.Net.ScatterGatherBuffers.AllocateMemoryChunk(Int32 newSize)
at System.Net.ScatterGatherBuffers..ctor(Int64 totalSize)
at System.Net.ConnectStream.EnableWriteBuffering()
at System.Net.HttpWebRequest.SetRequestSubmitDone(ConnectStream submitStream)
at System.Net.Connection.CompleteStartRequest(Boolean onSubmitThread, HttpWebRequest request, TriState needReConnect)
at System.Net.Connection.SubmitRequest(HttpWebRequest request, Boolean forcedsubmit)
at System.Net.ServicePoint.SubmitRequest(HttpWebRequest request, String connName)
at System.Net.HttpWebRequest.SubmitRequest(ServicePoint servicePoint)
at System.Net.HttpWebRequest.BeginGetRequestStream(AsyncCallback callback, Object state)
at System.Net.Http.HttpClientHandler.StartGettingRequestStream(RequestState state)
at System.Net.Http.HttpClientHandler.PrepareAndStartContentUpload(RequestState state)

显然， HttpWebRequest 也出现了类似的问题。如此处所讨论: http://support.microsoft.com/kb/908573 .

有没有办法设置 AllowWriteStreamBuffering对 false 的底层 Web 请求?我找不到任何。

干杯，

Answer 1

为了节省其他感兴趣的人的时间，我正在回答我自己的问题。

经过几次测试，异常似乎归结为与 HttpWebRequest 相同的问题。正如问题中所讨论的那样。我使用 Microsoft.AspNet.WebApi 版本 4.0.20710.0。

下面是两段等效的代码；前者在大文件上失败，而后者工作正常。

顺便说一句，尽管 HttpClient 的整体利益问题变得非常明显:-)

使用 HttpClient

var clientRef = new System.Net.Http.HttpClient(
    new HttpClientHandler()
    {
        Credentials = new System.Net.NetworkCredential(MyUsername, MyPassword)
    });
clientRef.BaseAddress = new Uri(serverAddress);
clientRef.DefaultRequestHeaders.ExpectContinue = false;
clientRef.PostAsync(
    MyFavoriteURL,
    new System.Net.Http.StreamContent(inputStream)).ContinueWith(
        requestTask =>
        {
            HttpResponseMessage response = requestTask.Result;
            response.EnsureSuccessStatusCode();
        }, TaskContinuationOptions.LongRunning).Wait();

使用 HttpWebRequest

// Preauthenticate
var req  = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(MyFavoriteURL);
req.Credentials = new System.Net.NetworkCredential(MyUsername, MyPassword);
req.Method = "POST";
req.PreAuthenticate = true;
req.Timeout = 10000;
using (var resp = (System.Net.HttpWebResponse)req.GetResponse())
{
     if (resp.StatusCode != System.Net.HttpStatusCode.Accepted && resp.StatusCode != System.Net.HttpStatusCode.OK)
     {
         throw new Exception("Authentication error");
     }
}

// Upload
req = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(MyFavoriteURL);
req.Credentials = new System.Net.NetworkCredential(MyUsername, MyPassword);
req.Method = "POST";
req.PreAuthenticate = true;
req.Timeout = 1200000;
req.ContentLength = inputStream.Length;
req.ContentType = "application/binary";
req.AllowWriteStreamBuffering = false;
req.Headers.ExpectContinue = false;
using (var reqStream = req.GetRequestStream())
{
    inputStream.CopyTo(reqStream);
}

using (var resp = (System.Net.HttpWebResponse)req.GetResponse())
{
    if (resp.StatusCode != System.Net.HttpStatusCode.Accepted && resp.StatusCode != System.Net.HttpStatusCode.OK)
    {
        throw new Exception("Error uploading document");
    }
}