Custom rewrite rules for pages

Question

I'm trying to get WordPress to recognize a URL structure like this:

example.com/parent/page/{id}/{first_name}/{last_name}

The basic ideea is that I need to access the id, first_name and last_name in my page and they have to come via the URL. So I have to put rules like:

(/some_page/child_page/)/([0-9]+)/([^/]+)/([^/]+) =>
index.php?pagename=$matches[1]&id=$matches[2]&fname=$matches[3]&lname=$matches[4]

for every page, by using the page_rewrite_rules filter.

The question is: How to I get the "pagename" for every page? The /some_page/child_page/ part. I can get the post_name but then I miss the parent, grandfather page.

Answer 1

The pattern WordPress uses to recognize pages is (.+?), which will match anything, but is not greedy, so it allows you to put something at the end. The following code works for me in WordPress 3.0.1: it places the extra pattern at the second-to-last place of the list, because the final pattern is so generic it will match every URL:

add_filter( 'page_rewrite_rules', 'wpse7243_page_rewrite_rules' );
function wpse7243_page_rewrite_rules( $rewrite_rules )
{
    // The most generic page rewrite rule is at end of the array
    // We place our rule one before that
    end( $rewrite_rules );
    $last_pattern = key( $rewrite_rules );
    $last_replacement = array_pop( $rewrite_rules );
    $rewrite_rules +=  array(
        '(.+?)/([0-9]+)/([^/]+)/([^/]+)/?$' => 'index.php?pagename=$matches[1]&id=$matches[2]&fname=$matches[3]&lname=$matches[4]',
        $last_pattern => $last_replacement,
    );
    return $rewrite_rules;
}

Be aware that pages, like any post, can also be split into multiple pages with the <!--nextpage--> snippet, and the normal URL for that is /pagename/2/, which might be confusing when you also have /pagename/3/jan/fabry/ where the 3 is an ID. You can change the pattern to include an optional page number at the end, so this can become /pagename/3/jan/fabry/2/ where the final 2 is the page number, and the first 3 is the ID.

If you are changing the rewrite rules I recommend my rewrite analyzer plugin (soon in the repository, but get the current version via Dropbox), it helps you debug these things.