There are 2 points of attack to cover when you are adding custom post type rewrite rules:
Rewrite rules
This happens when the rewrite rules are being generated in wp-includes/rewrite.php in WP_Rewrite::rewrite_rules(). WordPress allows you to filter the rewrite rules for specific elements like posts, pages and various types of archive. Where you see posttype_rewrite_rules the posttype part should be the name of your custom post type. Alternatively you can use the post_rewrite_rules filter as long as you don't obliterate the standard post rules too.
Next we need the function to actually generate the rewrite rules:
// add our new permastruct to the rewrite rules
add_filter( 'posttype_rewrite_rules', 'add_permastruct' );
function add_permastruct( $rules ) {
global $wp_rewrite;
// set your desired permalink structure here
$struct = '/%category%/%year%/%monthnum%/%postname%/';
// use the WP rewrite rule generating function
$rules = $wp_rewrite->generate_rewrite_rules(
$struct, // the permalink structure
EP_PERMALINK, // Endpoint mask: adds rewrite rules for single post endpoints like comments pages etc...
false, // Paged: add rewrite rules for paging eg. for archives (not needed here)
true, // Feed: add rewrite rules for feed endpoints
true, // For comments: whether the feed rules should be for post comments - on a singular page adds endpoints for comments feed
false, // Walk directories: whether to generate rules for each segment of the permastruct delimited by '/'. Always set to false otherwise custom rewrite rules will be too greedy, they appear at the top of the rules
true // Add custom endpoints
);
return $rules;
}
The main thing to watch out for here if you decide to play around is the 'Walk directories' boolean. It generates rewrite rules for each segment of a permastruct and can cause rewrite rule mismatches. When a WordPress URL is requested the rewrite rules array is checked from top to bottom. As soon as a match is found it will load whatever it has come across so for example if your permastruct has a greedy match eg. for /%category%/%postname%/ and walk directories is on it will output rewrite rules for both /%category%/%postname%/ AND /%category%/ which will match anything. If that happens too early you're screwed.
Permalinks
This is the function that parses the post type permalinks and converts a permastruct (eg '/%year%/%monthnum%/%postname%/') into an actual URL.
The next part is a simple example of what would ideally be a version of the get_permalink() function found in wp-includes/link-template.php. Custom post permalinks are generated by get_post_permalink() which is a much watered down version of get_permalink(). get_post_permalink() is filtered by post_type_link so we're using that to make a custom permastructure.
// parse the generated links
add_filter( 'post_type_link', 'custom_post_permalink', 10, 4 );
function custom_post_permalink( $permalink, $post, $leavename, $sample ) {
// only do our stuff if we're using pretty permalinks
// and if it's our target post type
if ( $post->post_type == 'posttype' && get_option( 'permalink_structure' ) ) {
// remember our desired permalink structure here
// we need to generate the equivalent with real data
// to match the rewrite rules set up from before
$struct = '/%category%/%year%/%monthnum%/%postname%/';
$rewritecodes = array(
'%category%',
'%year%',
'%monthnum%',
'%postname%'
);
// setup data
$terms = get_the_terms($post->ID, 'category');
$unixtime = strtotime( $post->post_date );
// this code is from get_permalink()
$category = '';
if ( strpos($permalink, '%category%') !== false ) {
$cats = get_the_category($post->ID);
if ( $cats ) {
usort($cats, '_usort_terms_by_ID'); // order by ID
$category = $cats[0]->slug;
if ( $parent = $cats[0]->parent )
$category = get_category_parents($parent, false, '/', true) . $category;
}
// show default category in permalinks, without
// having to assign it explicitly
if ( empty($category) ) {
$default_category = get_category( get_option( 'default_category' ) );
$category = is_wp_error( $default_category ) ? '' : $default_category->slug;
}
}
$replacements = array(
$category,
date( 'Y', $unixtime ),
date( 'm', $unixtime ),
$post->post_name
);
// finish off the permalink
$permalink = home_url( str_replace( $rewritecodes, $replacements, $struct ) );
$permalink = user_trailingslashit($permalink, 'single');
}
return $permalink;
}
As mentioned this a very simplified case for generating a custom rewrite ruleset and permalinks, and is not particularly flexible but it should be enough to get you started.
Cheating
I wrote a plugin that lets you define permastructs for any custom post types, but like you can use %category% in the permalink structure for posts my plugin supports %custom_taxonomy_name% for any custom taxonomies you have too where custom_taxonomy_name is the name of your taxonomy eg. %club%.
It will work as you'd expect with hierarchical/non-hierarchical taxonomies.
http://wordpress.org/extend/plugins/wp-permastructure/
