add_rewrite_rule not registering on Multisite

Question

I have a multisite install of WordPress. I have installed the plugin Monkeyman Rewrite Analyzer so I can see all the rules I have registered. The code below is how I am registering the rule:

 add_action( 'init', 'add_init_rules' );

 function add_init_rules() {
     add_rewrite_rule('^car/([^/]*)/([^/]*)/?','index.php?pagename=car&id=$matches[1]&make=$matches[2]','top');
 }

The rule I have added does not appear in the Monkeyman Rewrite Analyzer list and does not appear to make any difference to the site when trying to visit mysite.com/32423/testmake

Any suggestions?

Answer 1

Did you flush the rules after making this code?

Visit the Settings->Permalinks screen. This will cause a rule flush. Then check and see if your new rule appears.

Answer 2

The rule you added is a "non wp rule", that is, a rule added to htaccess. Sadly, with multisite these rules get completely ignored and don't get written to your htaccess. WordPress uses hardcoded htaccess rules when multisite is enabled. I've struggled with this myself and haven't found any solution yet (except editing htaccess directly).