Kohana 3 -> Checking if page with (URI) exists

With Kohana 3, I would like to get to know if a page with a by the user entered URI exists. So basically the user enters an URI, and I will say if it will give a (404) error or not.

I already tried this, but it didn't work:

<?php
 public function action_test_uri()
 {
    $r = Request::factory('this/uri/is/not/leading/to/a/valid/page');
    $test = $r->status;
    $test = ($test == 404) ? 'THIS PAGE DOESN\'T EXISTS' : '开发者_StackOverflow中文版THIS PAGE EXISTS';
    die($test);
 }
?>

Unfortunately this outputs 'THIS PAGE EXISTS'.

Is there anyone who does know the solution?

Thanks

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Retrieve all routes and test if any of them matches the URI. However, this does not tell you how the controller handles the URI. The controller might as well generate a 404, so the only sure way is to actually retrieve the page referred to by the URI.