Download file through code that has a redirect?

Question

I have some urls in the database. The problem is there urls are urls that redirect to what I want.

I have something like this

http://www.mytestsite.com/test/

Answer 1

I think you are after the HttpWebRequest.AllowAutoRedirect Property. The property gets or sets a value that indicates whether the request should follow redirection responses.

Example taken from MSDN

HttpWebRequest myHttpWebRequest=(HttpWebRequest)WebRequest.Create("http://www.contoso.com");    
myHttpWebRequest.MaximumAutomaticRedirections=1;
myHttpWebRequest.AllowAutoRedirect=true;
HttpWebResponse myHttpWebResponse=(HttpWebResponse)myHttpWebRequest.GetResponse();

Answer 2

I had issues trying to get HttpWebRequest to always fully redirect when using it with SharePoint external URLs; I simply couldn't get it to work.

After a lot of faffing about I discovered that this can be done with WebClient too and that proved more reliable for me.

To get that to work with WebClient you seem to have to create a class that derives from WebClient so that you can manually force AllowAutoRedirect to true.

I wrote up a bit more on this in this answer, which borrows its code from this question.

The key code was:

class CustomWebclient: WebClient
{
  [System.Security.SecuritySafeCritical]
  public CustomWebclient(): base()
 {
 }
 public CookieContainer cookieContainer = new CookieContainer();


 protected override WebRequest GetWebRequest(Uri myAddress)
 {
       WebRequest request = base.GetWebRequest(myAddress);
       if (request is HttpWebRequest)
      {
           (request as HttpWebRequest).CookieContainer =   cookieContainer;
           (request as HttpWebRequest).AllowAutoRedirect = true;
      }
      return request;
  }
}