Can not get URL using GetPageContext().getRequest().getRequestURI()

Hi guys,

I am coding a web application using ColdFusion 8.

The situation is as follow:

- I type https://mypage.com/aaa/bbb.html on web browser where aaa and bbb.html does not exist in my web folder.

- And this will drive the error 404 PageNotFound occurred, in the code that processing error 404, I tried to get URL aaa/bbb.html by using GetPageContext().getRequest().getRequestURI() but the result of this command is my created 404 error page.

- I also tried to get URL by using CGI, but also couldn't get it.

Can you guys show me the way to get URL when no page is found error occurred?

Thank you very much in advanced!