System.Net.HttpWebRequest.GetResponse() 错误"You must write ContentLength bytes to the request stream

Question

我有一个将文件上传到我们的服务器的方法。我在尝试上传大文件时看到标题中的错误。我尝试在 web.config 中从 35480 KB 增加 maxRequestLength，但我仍然看到错误。

<httpRuntime maxRequestLength="3548000" executionTimeout="1000" targetFramework="4.6.1"/>

我也尝试在 using 语句中发出请求，如这篇文章中所述 System.Net.ProtocolViolationException：在调用 [Begin]GetResponse 之前，您必须将 ContentLength 字节写入请求流，但无济于事。任何建议将不胜感激。

        HttpWebRequest webrequest = (HttpWebRequest)WebRequest.Create(uri);
        webrequest.CookieContainer = cookies;
        webrequest.ContentType = "multipart/form-data; boundary=" + boundary;
        webrequest.Method = "POST";
        // Build up the post message header
        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        sb.Append("--"); sb.Append(boundary); sb.Append("rn");
        sb.Append("Content-Disposition: form-data; name=""); sb.Append(fileFormName); 
        sb.Append(""; filename=""); sb.Append(Path.GetFileName(uploadfile)); sb.Append("""); sb.Append("rn");
        sb.Append("Content-Type: "); sb.Append("application/octet-stream"); sb.Append("rn");
        sb.Append("rn");            
        string postHeader = sb.ToString();
        byte[] postHeaderBytes = System.Text.Encoding.UTF8.GetBytes(postHeader);
        // Build the trailing boundary string as a byte array. ensuring the boundary appears on a line by itself
        byte[] boundaryBytes =  System.Text.Encoding.ASCII.GetBytes("rn--" + boundary + "rn");
        string strRead = "";
        FileStream fileStream = null;
        Stream requestStream = null;
        WebResponse responce = null;
        StreamReader responseStream = null;
        try
        {
            fileStream = new FileStream(uploadfile, FileMode.Open, FileAccess.Read);
            long length = postHeaderBytes.Length + fileStream.Length + boundaryBytes.Length;
            webrequest.ContentLength = length;
            using (requestStream = webrequest.GetRequestStream())
            {
                //requestStream = webrequest.GetRequestStream();
                // Write out our post header
                requestStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
                // Write out the file contents
                byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)fileStream.Length))];
                int bytesRead = 0;
                while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0) { requestStream.Write(buffer, 0, bytesRead); }
                // Write out the trailing boundary
                requestStream.Write(boundaryBytes, 0, boundaryBytes.Length);
                responce = webrequest.GetResponse();
            }
            responseStream = new StreamReader(responce.GetResponseStream());
            strRead = responseStream.ReadToEnd();
        }
        catch (Exception ex)
        {
                     // handle error
        }
        finally
        {
            if( fileStream != null ) fileStream.Close();
            if( requestStream != null ) requestStream.Close();
            if( responseStream != null ) responseStream.Close();
            if( responce != null ) responce.Close();
        }
        return strRead;

Answer 1

这是通过在system.webServer中设置maxAllowedContentLength来解决的。超出最大请求长度。