Filter posts by custom field (Advanced Custom Fields)

Question

I'm using Advanced Custom Fields and have been following along with this tutorial on Creating a WP archive with Custom Field Filter. In their example, they're using Radio Button Field; I would like to use the Checkbox Field for a custom post type called 'book', as some of my books have more than one 'book_type' associated with them.

Field name: book_type

Field type: Checkbox Field

Choices: men, women, children, accessories

My functions.php page looks like this:

add_action('pre_get_posts', 'my_pre_get_posts');

function my_pre_get_posts( $query ) {
if( is_admin() ) {
    return;
}

$book_format = $query->get('meta_query');
    if( !empty($_GET['book_type']) ) {
        $book_format[] = array(
            'key'       => 'type',
            'value'     => $_GET['book_type'],
            'compare'   => 'LIKE',
        );
    }

$query->set('meta_query', $book_format);
return;
}

Now, when I manually add my 'book_type' to my url like this:

dev.com/books?=men

it successfully shows all books related to men. But when I add the '|' seperator, as you do with an array, I get a blank page.

dev.com/books?=men|women|accessories

Am I doing something wrong here?

Any help is appreciated. Thanks in advance!

Answer 1

If you're receiving an array, your meta_query is going to change. LIKE will no longer be valid, you'd need to do an IN comparison at that point.

Also I'm not entirely convinced you're correctly passing a $_GET array