Comparision between Response.Redirect, Response.RedirectParmanent and Server.Transfer

It is to be noted, .NET has lately introduced <code>Response.RedirectParmanent() after a long await. The main motive of this is to have permanent response redirection to the Search Engines.

Response.RedirectParmanent() is an extension function introduced in .NET 4.0.
The main motive of it is to indicate the Response Code to the Search Engine that the page is moved permanently. The Response.Redirect generates Response code as 302 whereas <code><code>RedirectParmanent returns 301.

Thus say you have a page, and which is included to search engine for a long time, if you use Response.Redirect() it will not change this effect to the search engine(taking this a temporary change), while if you use Response.RedirectParmanent() it will take it as permanent.

If you want to write Response.RedirectParmanent() yourself the code will look like :

public static class Extensions
{
   public static void RedirectPermanent(this HttpResponse Response, 
                                         string absoluteUri)
   {
       Response.Clear();
       Response.Status = "301";
       Response.RedirectLocation = absoluteUri;
       Response.End();
   }
}

In case of Server.Transfer() the actual response is actually been updated. There is no effect to the search engine, and search engine will think the output is coming from the same page that is called. Let us give an example :

Say you have 2 pages (Page1 and Page2) where Page1 redirects to Page2.
In case of

1. Response.Redirect() : Search Engine will take this redirection as Temporary(Status 301) and always keep Page1 in its cache.

2. Response.RedirectParmanent() : Search Engine will take this a permanent redirection(Status 302) and will remove Page1 from its database and include Page2 for better performance on search.

3. Server.Transfer() : Search Engine will be unaware of any redirection been took place (Status 200) and will keep Page1 to its database. It will think Page1 is producing the output response of Page2.

When to use:

• Response.Redirect is perfect when your page is temporarily changed and will again be reverted to original within a short span of time.

• Response.RedirectParmanent() when you are thinking of deleting the original page totally after the search engines changes its database. 

• Server.Transfer() when you are thinking of keeping the page for ever, and to let search engine unaware of this redirection.