Apache directory index on demand - apache

Question

Within Apache, how can I call the default directory index creator on-demand?
Here's the situation. Requirement is to display, say, a default image file for a URL that corresponds to a directory. That's easy to do, using mod_dir. But a further requirement is that, when the image is clicked (in the browser), display a directory listing. Now I realize that can be done by writing some directory-listing code (in PHP, say). But that seems like re-inventing the wheel. So ideally I'd like to invoke the code in mod_autoindex directly.

Answer 1

This may well not be possible at all.
One possible, untested approach that may be worth a try:
Set up DirectoryIndex as you have it now
Build a conditional URL rewrite that is fired on the directory index, but only if a certain GET parameter - let’s say showlist- is not set to yes. For how to write a RewriteCond that checks for GET parameters in URLs, see this question. To address only directories, use
RewriteCond %{REQUEST_FILENAME} !-d
If that condition is not met, have RewriteRule redirect to the page with your image. That way, when I open a directory on your server, I will be taken to that page.
On the page with the image, have a link to the directory with the GET parameter specified:
http://my.domain/directoryname/?showlist=yes
That should not redirect back to the file with the image, but display Apache’s directory listing.