HTTP上传进度

本文关键字：HTTP | 更新日期: 2023-09-27 18:02:18

我正在上传一些表单数据，包括文件，到web服务器，需要跟踪上传进度。我通过将我的上传数据一点一点地复制到HttpWebRequest的请求流，并根据复制的字节数和总字节数更新进度条来做到这一点。根据另一个网站的说法，这将缓冲所有内容，之后实际的网络传输需要更长的时间。我应该设置request.AllowWriteStreamBuffering = false;来防止缓冲。不幸的是，当我这样做时，request.GetResponse()方法将永远阻塞。

下面是一些示例代码:

HttpWebRequest request = (HttpWebRequest) HttpWebRequest.Create(uri);
request.AllowAutoRedirect = false;
request.Method = "POST";
request.ContentType = "multipart/form-data; boundary=" + multipartBoundary;
Stream reqStream = request.GetRequestStream();
request.AllowWriteStreamBuffering = false;
postStream.Seek(0, SeekOrigin.Begin);
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = postStream.Read(buffer, 0, buffer.Length)) > 0)
{
    reqStream.Write(buffer, 0, bytesRead);
    int percentage = (int) (postStream.Position * 100 / postStream.Length);
    backgroundWorker.ReportProgress(percentage);
}
reqStream.Close();
HttpWebResponse response = (HttpWebResponse) request.GetResponse();

当我不设置AllowWriteStreamBuffering时，它都可以正常工作。这是怎么了?

HTTP上传进度

问题是设置AllowWriteStreamBuffering太晚了。

HttpWebRequest request = (HttpWebRequest) HttpWebRequest.Create(uri);
request.AllowWriteStreamBuffering = false;
request.SendChunked = true;
request.AllowAutoRedirect = false;
request.Method = "POST";
...

通过预先设置AllowWriteStreamBuffering，它还例外地告诉我必须设置SendChunked或指定内容长度(我现在手头没有)。

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