Adding pagination to sub-wp_query within a singular post page

Question

So my custom wordpress theme/site has a number of venues, e.g. "foo" which has a number of events and reviews.

So a venue ends up with a URL like,

http://www.example.local/places/my-place-name/

But in addition to rendering the venue's content (the_content()... etc) I'm rendering the events and reviews at that venue (the venue is a 'parent' as the event and review post types have the venue as it's 'parent')

So for this I'm running a custom wp_query for these two post types. I'm running into trouble as I can't paginate the results from my custom wp_query. Even if I want to roll my own pagination routine by getting the page number off the URL and then setting the 'offset' on the wp_query, wordpress doesn't like the additional parameters on the end of the URL. For example if I go to:

http://www.example.local/places/my-place-name/mypage/2/

Simply renders a 404 not found. I'd like to avoid using a query string style URL such as

http://www.example.local/places/my-place-name/?mypage=2

As this looks a bit of a mess.

Any guidance on how to make pagination work for the custom wp_query within the post's page (or even how to get wordpress to allow me to add additional pagination parameters to my URL) would be great.

Answer 1

You need to add a query var and rewrite rule to make that work.

First, add the query var to WordPress query vars array in your theme's functions.php:

add_filter( 'query_vars', 'wpa58904_query_vars' );
function wpa58904_query_vars( $query_vars ){
    $query_vars[] = 'my_page';
    return $query_vars;
}

Then add a rewrite rule with your desired pattern that sets your custom page query var:

add_action( 'init', 'wpa58904_rewrites' );
function wpa58904_rewrites(){
    add_rewrite_rule(
        'places/([^/]+)/mypage/([0-9]+)/?$',
        'index.php?venue=$matches[1]&my_page=$matches[2]',
        'top'
    );
}

Then in your template you can access the value of my_page with

get_query_var( 'my_page' );

Be sure to visit your Permalinks Settings page after adding rewrite rules to flush the rewrites cache.