When a user (or a bot) request on non existing page, I want to redirect him to the search results. I prefere to do it with the .htaccess file using something like:
ErrorDocument 404 /recherche?search_query=${REQUEST_URI}
However, it fails; the web browser is redirected to the URL recherche?search_query=${REQUEST_URI} , ${REQUEST_URI} and is not replaced, it is as you can read it here.
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.
