301 redirect on sub domain

Question

To handle 301 redirect we have made changes in pipeline and written following class

public class CustomRedirect301 : PreprocessRequestProcessor
{
    public override void Process(PreprocessRequestArgs args)
    {
        var targeturl = objDB.GetTargetURL(args.Context.Request.Url.PathAndQuery.TrimEnd(new[] { '/' });)
        args.Context.Response.RedirectPermanent(targeturl, true);
    }
}

In GetTargetURL function we pass incoming URL part only after domain for example incoming request is www.mysite.com/healthcare we pass /healthcare and this function return actual url where user should redirect let's say www.mysite.com/part-1/part-2/healthcare

We maintain this mapping in database table with two column UrlFrom and UrlTo so in this case

UrlFrom is /healthcare

UrlTo is www.mysite.com/part-1/part-2/healthcare

But now we have one request where we have to redirect abc.mysite.com to www.mysite.com/part-1/part-2/part-3

In this case we don't have any URL part after domain to pass as input parameter in GetTargetURL function so how can we achieve this.

Environment: Sitecore 8.1 MVC / Multisite implementation

Answer 1

If you don't want to use URL Rewrite Module (and from your comment I see you don't want it), you need to change the code of your processor slightly.

Add an entry like

UrlFrom ://abc.mysite.com
UrlTo www.mysite.com/part-1/part-2/part-3

and call GetTargetURL as you do now:

var key = args.Context.Request.Url.PathAndQuery.TrimEnd(new[] { '/' });

// for "abc.mysite.com" key will be an empty string
if (string.IsNullOrEmpty(key))
{
    // for "abc.mysite.com" it will return "://abc.mysite.com"
    key = string.Format("://" + Request.Url.DnsSafeHost);
}
var targeturl = objDB.GetTargetURL(key);

If you do this like that, you don't need to write any custom code that will check if domain is abc.mysite.com. And you will be able to add more subdomain redirects without any code changes.

One important thing is: you need to make should that either your database call are really efficient or cached. You don't want to make a call to database for every home page request if it's not necessary.