.htaccess rule to redirect from 404 to search results

Question

When a user (or bot) request on non existing page, i want to redirect him to the search results. I Prefere to do it the .htaccess file.

Things like

ErrorDocument 404 /recherche?search_query=${REQUEST_URI} 

failled : the webbrowser is redirected to the url recherche?search_query=${REQUEST_URI} , ${REQUEST_URI} is not replaced, it is as you can read it here.

(Edited thanks to Aerik)

Answer 1

The variable replacement will not work in ErrorDocument directive -- it will pass URL as is with no changes (maybe there are some special module that will perform such replacement -- I do not know).

If you want to use ErrorDocument directive, then you will have to grab the originally requested URL in the script itself (e.g. $_SERVER['REQUEST_URI'] in PHP). You can pass some special parameter to tell your 404 handler to execute such look up, e.g. ErrorDocument 404 /recherche?special-search=yes.

Another approach would be to use mod_rewrite, where such replacement is possible. For example:

Options +FollowSymLinks
RewriteEngine On

# redirect all requests to non-existing resources to special handler
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule .* /recherche?search_query=%{REQUEST_URI} [L,R=404]

If you are using mod_rewrite already .. then such rule should be placed somewhere at the end of your rules list so it does not conflict with other rules.