Using WebClient in C# is there a way to get the URL of a site after being redirected?

Question

Using the WebClient class I can get the title of a website easily enough:

WebClient x = new WebClient();    
string source = x.DownloadString(s);
string titl         


        

Answer 1

In case you are only interested in the redirect URI you can use this code:

public static string GetRedirectUrl(string url)
{
     HttpWebRequest request = (HttpWebRequest) HttpWebRequest.Create(url);
     request.AllowAutoRedirect = false;

     using (HttpWebResponse response = HttpWebResponse)request.GetResponse())
     {
         return response.Headers["Location"];
     }
}

The method will return

• null - in case of no redirect
• a relative url - in case of a redirect

Please note: The using statement (or a final response.close()) is essential. See MSDN Library for details. Otherwise you may run out of connections or get a timeout when executing this code multiple times.

Answer 2

Ok this is really hackish, but the key is to use the HttpWebRequest and then set the AllowAutoRedirect property to true.

Here's a VERY hacked together example

        HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://tinyurl.com/dbysxp");
        req.Method = "GET";
        req.AllowAutoRedirect = true;
        WebResponse response = req.GetResponse();

        response.GetResponseStream();
        Stream responseStream = response.GetResponseStream();

        // Content-Length header is not trustable, but makes a good hint.
        // Responses longer than int size will throw an exception here!
        int length = (int)response.ContentLength;

        const int bufSizeMax = 65536; // max read buffer size conserves memory
        const int bufSizeMin = 8192;  // min size prevents numerous small reads

        // Use Content-Length if between bufSizeMax and bufSizeMin
        int bufSize = bufSizeMin;
        if (length > bufSize)
            bufSize = length > bufSizeMax ? bufSizeMax : length;

        StringBuilder sb;
        // Allocate buffer and StringBuilder for reading response
        byte[] buf = new byte[bufSize];
        sb = new StringBuilder(bufSize);

        // Read response stream until end
        while ((length = responseStream.Read(buf, 0, buf.Length)) != 0)
            sb.Append(Encoding.UTF8.GetString(buf, 0, length));

        string source = sb.ToString();string title = Regex.Match(source, 
        @"\<title\b[^>]*\>\s*(?<Title>[\s\S]*?)\</title\>",RegexOptions.IgnoreCase).Groups["Title"].Value;

enter code here