Downloading a file, and I get Content-Length header is Invalid

Question

I'm downloading a file, from a webserver, using the code below, and am recieving this error:

The Error: Error saving file from URL:The server committed a protocol violation.

Section=ResponseHeader Detail='Content-Length' header value is invalid

From running Fiddler while this is running, it says:

Content-Length response header is not a valid unsigned integer Content-Length: 13312583

The Code:

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;
        }

Update: If I pass the URL straight into a browser, the file is downloaded successfully, and the error is thrown on the GetResponse line.

Update 2: I get the same error with WebClient.Downloadfile:

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

    return true;
}

Update 3: Having retrieved the other headers in the message (using Fiddler), they are:

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

Are there other HTTP headers present?

It might have to do with the 'Transfer-Encoding' header or similar rules. For more specific information about these headers and their effect on the Content-Length header can be found at the W3C website and More W3C website

Hope this helps,

Answer 2

Could you not use WebClient.DownloadFile instead?

Answer 3

Can you get a tracelog of your application (http://ferozedaud.blogspot.com/2009/08/tracing-with-systemnet.html) and put it on pastebin? Then we can try to help.

The protocolviolationexception may be due to a number of things. One of them could be that the server is advertizing a content length of 100, and sending less (or more) data than that.