下载文件，我得到 Content-Length header is Invalid

Question

我正在使用以下代码从网络服务器下载文件，但收到此错误：

错误： 从 URL 保存文件时出错：服务器违反了协议。

Section=ResponseHeader Detail='Content-Length' 标头值无效

在运行时运行 Fiddler，它说：

Content-Length 响应标头不是有效的无符号整数 内容长度：13312583

代码：

public static bool SaveFileFromURL(string url, string destinationFileName, int timeoutInSeconds)
        {
            //SetAllowUnsafeHeaderParsing20();
            Configuration config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            SettingsSection section = (SettingsSection)config.GetSection("system.net/settings");
            section.HttpWebRequest.UseUnsafeHeaderParsing = false;
            config.Save();

            // Create a web request to the URL
            HttpWebRequest MyRequest = (HttpWebRequest)WebRequest.Create(url);
            MyRequest.UseDefaultCredentials = true;
            MyRequest.ContentLength = 0;

            MyRequest.Timeout = timeoutInSeconds * 1000;
            try
            {
                // Get the web response
                HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();

                // Make sure the response is valid
                if (HttpStatusCode.OK == MyResponse.StatusCode)
                {
                    // Open the response stream
                    using (Stream MyResponseStream = MyResponse.GetResponseStream())
                    {
                        // Open the destination file
                        using (FileStream MyFileStream = new FileStream(destinationFileName, FileMode.OpenOrCreate, FileAccess.Write))
                        {
                            // Create a 4K buffer to chunk the file
                            byte[] MyBuffer = new byte[4096];
                            int BytesRead;
                            // Read the chunk of the web response into the buffer
                            while (0 < (BytesRead = MyResponseStream.Read(MyBuffer, 0, MyBuffer.Length)))
                            {
                                // Write the chunk from the buffer to the file
                                MyFileStream.Write(MyBuffer, 0, BytesRead);
                            }
                        }
                    }
                }
            }
            catch (Exception err)
            {
                throw new Exception("Error saving file from URL:" + err.Message, err);
            }
            return true;
        }

更新：如果我将 URL 直接传递给浏览器，则文件下载成功，并在 GetResponse 行抛出错误。

更新 2：我收到与 WebClient.Downloadfile 相同的错误：

public static bool DL_Webclient(string url, string destinationFileName)
{
    WebClient myWebClient = new WebClient();
    myWebClient.UseDefaultCredentials = true;
    myWebClient.DownloadFile(url, destinationFileName);

    return true;
}

更新 3：检索到消息中的其他标头（使用 Fiddler）后，它们是：

HTTP/1.1 200 OK
Connection: close
Date: Wed, 03 Mar 2010 08:43:06 GMT
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
Content-Length: 13314320
Content-Type: application/x-evsaveset
Set-Cookie: ASPSESSIONIDQQCQSCRC=CFHHJHADOIBCFAFOHFJCDNEG; path=/
Cache-control: private

Answer 1

是否存在其他 HTTP 标头？

这可能与“Transfer-Encoding”标头或类似规则有关。有关这些标头及其对 Content-Length 标头的影响的更多具体信息，请参见 W3C website 和 More W3C website

希望这会有所帮助，

Answer 2

你能不改用WebClient.DownloadFile吗？