C# 实现对微博短网址的重定向还原

private string GetOrignalLink(string link)
{
using (WebClient client = new MyWebClient())
{
client.Headers.Add("Referer", link);
Stream stream = null;
try
{
stream = client.OpenRead(link);
return client.ResponseHeaders["Location"];
}
catch (Exception)
{
throw;
}
finally
{
if (stream != null) stream.Close();
}
}
}

internal class MyWebClient : WebClient
{
protected override WebRequest GetWebRequest(Uri address)
{
HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
request.AllowAutoRedirect = false;
return request;
}
}