algolia_save_post.php

<?php

add_action('save_post', 'algolia_save_post', 10, 3);

function algolia_save_post($id, $post, $update) {
    global $algolia;

    $post_type = $post->post_type;
    $post_status = $post->post_status;

    $searchable_post_types = get_post_types(
        array(
            'public' => true,
            'exclude_from_search' => false
        )
    );

    if (in_array($post_type, $searchable_post_types)) {
        // Only reindex posts that have been published or trashed
        $is_invalid_status = $post_status != 'publish' && $post_status != 'trash';

        if (wp_is_post_revision($id) || wp_is_post_autosave($id) || $is_invalid_status) {
            return $post;
        }

        // Serialize post
        $filter_name = $post_type.'_to_record';
        $records = (array) apply_filters($filter_name, $post);

        // Get global index
        $canonical_index_name = apply_filters('get_algolia_index_name', 'global_search');
        $global_index = $algolia->initIndex($canonical_index_name);

        // Delete all records using the distinct_key attribute
        $filter_to_delete = 'distinct_key:'.$records[0]['distinct_key'];

        // Make sure to delete split records if they exist
        $global_index->deleteBy(['filters' => $filter_to_delete]);

        if ($post_status == 'publish') {
            $global_index->saveObjects($records);
        }
    }

    return $post;
}