Pagination problems with multiple custom post type archive pages

Question

I'm at the end of my tether now. Really need some help! Here's the setup...

I have 2 custom post types in my functions.php:

// Register the events post type
function events() {
    $labels = array(
        'name' => _x('Evenemang', ''),
        'singular_name' => _x('Evenemang', ''),
        'menu_name' => _x('Evenemang', ''),
        'name_admin_bar' => _x('Evenemang', ''),
        'add_new' => _x('Skapa ny', 'evenemang'),
        'add_new_item' => __('Skapa nyt evenemang'),
        'search_items' => __('Sök evenemang'),
        'not_found' => __('Hittade inga evenemang.'),
        'not_found_in_trash' => __('Inga evenemang hittades i papperskorgen.'),
    );
    $args = array(
        'labels' => $labels,
        'public' => true,
        'publicly_queryable' => true,
        'show_in_menu' => true,
        'has_archive' => true,
        'rewrite' => array('slug' => 'evenemang'),
        'query_var' => 'evenemang',
        'menu_icon' => 'dashicons-calendar-alt',
        'supports' => array('title', 'editor', 'thumbnail')
    );
    register_post_type('evenemang', $args);
}
add_action('init', 'events');

// Register the recipes post type
function recipes() {
    $labels = array(
        'name' => _x('Recept', ''),
        'singular_name' => _x('Recept', ''),
        'menu_name' => _x('Recept', ''),
        'name_admin_bar' => _x('Recept', ''),
        'add_new' => _x('Skapa ny', 'recept'),
        'add_new_item' => __('Skapa ny recept'),
        'search_items' => __('Sök recept'),
        'not_found' => __('Hittade inga recept.'),
        'not_found_in_trash' => __('Inga recept hittades i papperskorgen.'),
    );
    $args = array(
        'labels' => $labels,
        'public' => true,
        'publicly_queryable' => true,
        'show_in_menu' => true,
        'has_archive' => true,
        'rewrite' => array('slug' => 'recept'),
        'query_var' => 'recept',
            'menu_icon' => 'dashicons-carrot',
        'supports' => array('title', 'thumbnail')
    );
    register_post_type('recept', $args);
}
add_action('init', 'recipes');

For each of these 2 I have an archive-{post_type}.php, and i'm using <?php echo paginate_links(); ?> to spit out the pagination links, here's archive-evenemang.php:

<?php get_header(); ?>

    <div class="list">
        <?php
        $today = date('Ymd');
        $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
        $args = array(
            'posts_per_page' => 8,
            'post_type' => 'evenemang',
            'meta_key' => 'event_date',
            'orderby' => 'meta_value_num',
            'order' => 'ASC',
            'paged' => $paged,
            'meta_query' => array(
                array(
                    'key' => 'event_date',
                    'compare' => '>=',
                    'value' => $today
                )
            )
        );
        ?>
        <?php $posts = get_posts($args); foreach ($posts as $post) : setup_postdata($post); ?> 
            <h1><?php the_title(); ?></h1>
        <?php endforeach; wp_reset_postdata(); ?>
    </div>
    <div class="pagination">
        <?php echo paginate_links(); ?>
    </div>

<?php get_footer(); ?>

and here's archive-recept.php:

<?php get_header(); ?>

    <div class="list">
        <?php
        $today = date('Ymd');
        $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
        $args = array(
            'posts_per_page' => 8,
            'post_type' => 'recept',
            'orderby' => 'title',
            'order' => 'ASC',
            'paged' => $paged
        );
        ?>
        <?php $posts = get_posts($args); foreach ($posts as $post) : setup_postdata($post); ?> 
            <h1><?php the_title(); ?></h1>
        <?php endforeach; wp_reset_postdata(); ?>
    </div>
    <div class="pagination">
        <?php echo paginate_links(); ?>
    </div>

<?php get_footer(); ?>

As you can see they are set up exactly the same in functions.php, and use the basically the same archive template (with a minor adjustment to the $args in the query).

The "evenemang" page works perfectly, it shows the results, the pagination buttons and i can access mydomain.com/evenemang/page/2/.

The "recept" page also works, it shows the results, BUT no pagination buttons and if i try and access mydomain.com/recept/page/2/ it just goes to the front page.

Why does it work for one and not the other? Do i need to change some args inside the paginate_links() function? A problem with using get_query_var('paged') on multiple archives? Is it a .htaccess problem?

Answer 1

Your problem comes from a fundamental misunderstanding of how WordPress loads the main loop.

Here you have a main query that goes and grabs the posts to display in your post type archive. It then decides to load archive-recept.php based on that query.

The call to paginate_links then provides the pagination for that main query. However, the main query isn't being used.

Instead what you're doing is ignoring the main query, calling your own query ( doubling the DB work involved ), then expecting the pagination links to give you pagination for your get_posts query, rather than the main query.

This is functionally equivalent to calling query_posts, which as we know is bad practice.

Instead, use the pre_get_posts filter to modify the main query before it happens, e.g. something similar to:

function wpse182971( $query ) {
    if ( $query-> is_post_type_archive && $query->is_main_query() ) {
        $query->set( 'posts_per_page', '8' );
    }
}
add_action( 'pre_get_posts', 'wpse182971' );