WordPress functions that I tend to write often

wordpress-missing-functions.php

<?php

/**
 * Get a WP_Post object by its slug ( post_name )
 * 
 * @param $post_name
 *
 * @return WP_Post|null
 */
function get_post_by_slug( $post_name ) {
  $post_id = get_post_id_by_slug( $post_name );

  if( $post_id ) {
    return get_post( $post_id );
  }

  return null;
}

/**
 * Get post ID by its slug (post_name)
 * @param $post_name
 *
 * @return int|null
 */
function get_post_id_by_slug( $post_name ) {
  global $wpdb;
  $post_id = $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE post_name = %s LIMIT 1", $post_name ));
  
  if ( $post_id ) {
    return $post_id;
  }
  
  return null;
}

/**
 * Get term object by its slug
 *
 * @param $term_slug
 *
 * @return WP_Term|null
 */
function get_term_by_slug( $term_slug ){
  $taxonomy = get_term_taxonomy_by_slug( $term_slug );
  if ( $taxonomy ){
    return get_term_by( 'slug', $term_slug, $taxonomy );
  }

  return null;
}

/**
 * Get a term's taxonomy by its slug
 *
 * @param string $term_slug
 *
 * @return string|null
 */
function get_term_taxonomy_by_slug($term_slug) {
  global $wpdb;
  $taxonomy = $wpdb->get_var( $wpdb->prepare( "SELECT term_taxonomy.taxonomy FROM $wpdb->term_taxonomy AS term_taxonomy LEFT JOIN $wpdb->terms AS terms ON term_taxonomy.term_id = terms.term_id WHERE terms.slug = %s LIMIT 1", $term_slug) );

  if ( $taxonomy ){
    return $taxonomy;
  }

  return null;
}

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