Database Theory, Elasticsearch, Search, WordCamps, WordPress Plugins

ElasticPress at WordCamp Paris

This weekend I presented at WordCamp Paris 2015. My session was titled “Modernizing WordPress Search with Elasticsearch”. The talk ran through issues with WordPress search, what Elasticsearch is, setting up an Elasticsearch cluster, and configuring ElasticPress.

Elasticsearch is a very exciting technology and I am thrilled at the chance to spread information about it. I (and 10up in general) am very proud of the work we have done on ElasticPress. My hope is that more people will install the plugin and give us feedback as a result of the talk.

Here are my slides for the talk:

Don’t forget that comprehensive documentation for ElasticPress lives on Github.

Database Theory, WordPress Code Techniques

A Performant Way to Feature Posts

In a past blog post I explained why featuring posts using a taxonomy term is much more performant than using a meta query. The comment I get from people is “that’s awesome, but using tags to feature a post is not a good user experience”. I agree, attaching a “featured” tag to featured posts, while performant is not a good experience for users because it leaves room for error on the admin side and shows the “featured” tag to users on the front end (if you are listing your tags).

Thankfully, there is a much better way to do this. We can create a small meta box with a “Featured Post” checkbox. This checkbox will add/remove a term in a hidden taxonomy from the post. Here is what the meta box will look like in WordPress 3.9:

Featured post meta box

I will take you through the code necessary to set this up. First we need to register a private taxonomy for internal use:

function tl_register_taxonomy() {
  $args = array(
    'hierarchical' => false,
    'show_ui' => false,
    'show_admin_column' => false,
    'query_var' => false,
    'rewrite' => false,

  register_taxonomy( 'tl_post_options', array( 'post' ), $args );
add_action( 'init', 'tl_register_taxonomy' );

Now let’s write the code that actually associates the taxonomy term with featured posts. This will hook onto the “save_post” action.

function tl_save_post( $post_id ) {
  if ( ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) || ! current_user_can( 'edit_post', $post_id ) || 'revision' == get_post_type( $post_id ) )

  if ( ! empty( $_POST['additional_options'] ) && wp_verify_nonce( $_POST['additional_options'], 'additional_options_action' ) ) {
    if ( ! empty( $_POST['tl_featured'] ) ) {
      $featured = term_exists( 'tl_featured', 'tl_post_options' );
      if ( empty( $featured ) ) {
        $featured = wp_insert_term( 'tl_featured', 'tl_post_options' );
      wp_set_post_terms( $post_id, array( (int) $featured['term_id'] ), 'tl_post_options' );
    } else {
      wp_set_post_terms( $post_id, array(), 'tl_post_options' );
add_action( 'save_post', 'tl_save_post' );

Next, we need to output a meta box with a checkbox. If this checkbox is checked, the post is marked as featured and the appropriate information is sent to the “save_post” hook on POST.

function tl_meta_box_additional_options( $post ) {
  wp_nonce_field( 'additional_options_action', 'additional_options' );
  $featured = has_term( 'tl_featured', 'tl_post_options', $post );
  echo 'Featured: <input type="checkbox" name="tl_featured" value="1" ' . ( ( $featured ) ? 'checked="checked"' : '' ) . '>';

Don’t forget we need to actually register our new meta box:

function tl_add_meta_boxes() {
  add_meta_box( 'tl_additional_options', 'Additional Options', 'tl_meta_box_additional_options', 'post', 'side' );
add_action( 'add_meta_boxes', 'tl_add_meta_boxes' );

Querying for posts on the front end is super easy! Here is an example query:

$query = new WP_Query( array(
  'tl_post_options' => 'tl_featured'
  'post_status' => 'publish',
  'post_type' => 'post',
) );