Martin Greenwood

The server logs were empty, bar a few notices about undefined Vars…

Weirdly, started working again fine this morning!

Turns out i had to add this to the functions.php file.

// MAKE API FILTERABLE
add_action( 'rest_api_init', 'post_meta_register' );
function post_meta_register() {
    register_api_field( 'post',
        'testing',
        array(
            'get_callback'    => 'get_post_meta',
            'update_callback' => null,
            'schema'          => null,
        )
    );
}

function get_post_meta( $object, $field_name, $request ) {
    return get_post_meta( $object[ 'id' ], $field_name, true );
}

add_filter( 'rest_query_vars', 'allow_meta' );
function allow_meta( $valid_vars ) {

        $valid_vars = array_merge( $valid_vars, array( 'meta_key', 'meta_value' ) );
        return $valid_vars;
}