add_query_arg to compare and display events from a certain date

Question

I have archive-events.php file that sorts custom post type 'events' via WP_Query using custom field that is date formatted YYYYMMDD (20150215) like this:

$args = array(
    'post_type'     => 'events',
    'posts_per_page'=> 10,
    'meta_key'      => 'wpcf-sort-events',
    'orderby'       => 'meta_value_num',
    'order'         => 'ASC'
);
$wp_query = new WP_Query( $args );

Then I made a widget that displays custom calendar with date links to compare custom field dates via add_query_arg and display events archived from that date onwards like this:

$day = I get the day for the calendar before this... 01
$date = I get the full date (Ymd 20150501) from calendar widget to compare
$arrayargs = array(
    'meta_query' => array(
         'key'        => 'wpcf-sort-events',
         'value'      => $date,
         'compare'    => '>='
         ),
     );                                                                                                                                                         

$output = '<a href="' . add_query_arg( $arrayargs ) . '>' . $day . '</a> ';

This creates a link like this: http://mediterranean.life/events/?meta_query%5Bkey%5D=wpcf-sort-events&meta_query%5Bvalue%5D=20150501&meta_query%5Bcompare%5D=%3E

But I get all events (no matter the custom date) sorted ASC like query in archive-events.php, it ignores meta_query via link...

I have tried creating a link with a full query like this, but also failed...

$arrayargs = array(
            'post_type' => 'events',
            'meta_key' => 'wpcf-sort-events',
            'meta_query' => array(
                'key' => 'wpcf-sort-events',
                'value' => $date,
                'compare' => '>='
                ),
            'orderby' => 'meta_value_num',
            'order' => 'ASC'
        );                                                                                                                                                          

        $output = '<a href="' . add_query_arg( $arrayargs ). '>' . $day . '</a> ';

Lost in space... any ideas?

Answer 1

As you can see in your custom WP_Query, you pass hardcoded aguments, you are not evaluating the arguments passed in the URL, so they does not affect to the result.

In your case, it seems that using a custom query for the archive template is the bad way. When you request the archive template, the events for the archive have been already queried and you are refusing the results and making a new secondary query. Instead, you should use pre_get_posts action hook to alter the main query before it is executed, so you get the events you want in the archive template without the need of a secondary template.

add_action( 'pre_get_posts', function( $query) {

   if(isset($query->query_vars['action']) && $query->query_vars['action'] == 'search'){

       //Check that is the main query, not secondary, that we are not in admin side
       //and check that $query is the for the events archive

       if($query->is_main_query() && !is_admin() && is_post_type_archive('events') ) {

           //Get the values passed in the URL and pass them to the query
           if( ! empty( $_GET['meta_query'] ) ) {
               //You may need some validation/sanitization in $_GET['meta_query'] befor use it
               $query->set( 'meta_query', $_GET['meta_query'] );
           }


       }

   }


} );