pre_get_posts filter using numeric meta_query comparison (from dates)

Question

I have an expiry date ACF field 'post_end_date' which has been applied to multiple post types, including 'post'.

I'm trying to filter out any posts, across the entire site, where today's date is greater than the value 'post_end_date'; in other words the post has expired. I've checked that 'post_end_date' value returns a number in the same format as date('Ymd'). e.g.

echo date('Ymd'); // returns 20161128 for today
echo get_field('post_end_date'); // returns 20161127 for yesterday

I figured the best way would be to just do a numerical comparison between today's date and 'post_end_date' value.

This is my code:

  function expiry_filter($query) {

    if( !is_admin() && $query->is_main_query() ) :

      $today = $expire = date('Ymd');

      if ( get_field('post_end_date') ) :
        $expire = get_field('post_end_date');
      endif;

      $query->set( 'meta_query', array(
        array(
         'key'     => $expire,
         'value'   => $today,
         'compare' => '<',
         'type'    => 'NUMERIC'
        )
      ));

    endif;
  }
  add_action( 'pre_get_posts', 'expiry_filter' );

At this point, I was just trying to get it to work for the 'post' post type. I have checked that I haven't used the wrong 'compare' operator. I've tried with and without the $query->is_main_query() conditional.

The result I'm getting with the code above is ALL posts are being filtered out.

Can someone suggest what I might be doing wrong here?

Thanks in advance.

Answer 1

As mentioned in the comments you an issue in your meta query, as you set the key to 20161126 or similar. Instead key should be filled with your meta key post_end_date. Meta query also support multiple arrays to combine your query to also include posts where the meta key is not set. The example would be something like the following:

function expiry_filter($query) {
  if( !is_admin() && $query->is_main_query() ) {
    $expire = get_field('post_end_date') ? : date('Ymd');
    $query->set( 'meta_query', [
      'relation' => 'OR',
      [
       'key'     => 'post_end_date',
       'value'   => $expire,
       'compare' => '>=',
       'type'    => 'NUMERIC',
      ],
      [
       'key'     => 'post_end_date',
       'compare' => 'NOT EXISTS',
      ],
    ]);
  }
}
add_action( 'pre_get_posts', 'expiry_filter' );

Answer 2

Have you tried using meta_key, meta_value and meta_compare?

function expiry_filter( $query ) {

    if ( ! is_admin() && $query->is_main_query() ) :

        $query->set( 'meta_key', 'post_end_date' );
        $query->set( 'meta_value', date('Ymd') );
        $query->set( 'meta_compare', '>' );

    endif;
}

add_action( 'pre_get_posts', 'expiry_filter' );

Or maybe trying to use the DATE type when using meta_query?

function expiry_filter( $query ) {

  if ( ! is_admin() && $query->is_main_query() ) :

      $query->set( 'meta_query', array(
          array(
              'key'     => 'post_end_date',
              'value'   => date( 'Ymd' ),
              'compare' => '>=',
              'type'    => 'DATE'
          )
      ) );

  endif;
}
add_action( 'pre_get_posts', 'expiry_filter' );

Or just using the cleaned up version of your function

function expiry_filter( $query ) {

  if ( ! is_admin() && $query->is_main_query() ) :

      $query->set( 'meta_query', array(
          array(
              'key'     => 'post_end_date',
              'value'   => date( 'Ymd' ),
              'compare' => '>',
              'type'    => 'NUMERIC'
          )
      ) );

  endif;
}
add_action( 'pre_get_posts', 'expiry_filter' );