在处理潜在的覆盖后，如何推迟ASP.NET MVC的“默认”HttpHandler？

I need to implement a custom handler for MVC that gives me the first look at URLs requests to determine if it should rewrite the urls before submitting the URL to the routing engine. Any pattern is a candidate for the redirect, so I need to intercept the URL request before the standard MVC routing engine takes a look at it. I need to implement a custom handler for MVC th