Is Wordpress API visible from PHP file called in htaccess

Question

I'm trying to add some rewriterules in the .htaccess file to deal with hotlinked images - specifically I want to add the URL from the post where the image appeared to the header location information of the hotlinked image request.

I've got working htaccess & PHP code to add the header info, but in order to make it work, I need to be able to somehow look up the URL for the post from the image URL (this blog has a unique post for each image). I've got working code to do this, but it uses the Wordpress API, and when I try to call it none of the functions are recognized.

I'm thinking that maybe calling the API from htaccess isn't possible... like it's out of scope, or I'm calling from a place that can't see Wordpress or something? I'm wondering if there's a way to make Wordpress API calls accessible from htaccess - or if anybody has any suggestions for a workaround.

The only thing I can think of would be to try to query the database directly through MySQL, but I'm a bit nervous about doing that, and I'm not quite sure I understand the data structure fully.

Any suggestions would be welcomed!

Answer 1

The .htaccess is parsed before WordPress is loaded, so you don’t get access to WordPress data.

You can make the redirect in WordPress, in a plugin: Hook into 404_template and inspect $_SERVER['REQUEST_URI'] with parse_url(). You should be able to find the matching post for the image then.
You did not write how the permalinks for these posts are built, so we cannot offer a more specific solution.

Answer 2

To access your WordPress functions within a standalone PHP file, add the two following lines at the beginning of your PHP file:

define( 'WP_USE_THEMES', false );
require('wp-blog-header.php'); # or modify to match your current wp-blog-header.php file