/inc/class-wpseo-replace-vars.php

<?php 
/** 
 * @package    WPSEO\Internals 
 * @since      1.5.4 
 */ 
 
// Avoid direct calls to this file. 
if ( ! defined( 'WPSEO_VERSION' ) ) { 
  header( 'Status: 403 Forbidden' ); 
  header( 'HTTP/1.1 403 Forbidden' ); 
  exit(); 
} 
 
/** 
 * Class: WPSEO_Replace_Vars 
 * 
 * This class implements the replacing of `%%variable_placeholders%%` with their real value based on the current 
 * requested page/post/cpt/etc in text strings. 
 */ 
class WPSEO_Replace_Vars { 
 
  /** 
   * @var    array    Default post/page/cpt information 
   */ 
  protected $defaults = array( 
      'ID' => '',  
      'name' => '',  
      'post_author' => '',  
      'post_content' => '',  
      'post_date' => '',  
      'post_excerpt' => '',  
      'post_modified' => '',  
      'post_title' => '',  
      'taxonomy' => '',  
      'term_id' => '',  
      'term404' => '',  
 ); 
 
  /** 
   * @var object    Current post/page/cpt information 
   */ 
  protected $args; 
 
  /** 
   * @var    array    Help texts for use in WPSEO -> Titles and Meta's help tabs 
   */ 
  protected static $help_texts = array(); 
 
  /** 
   * @var array    Register of additional variable replacements registered by other plugins/themes 
   */ 
  protected static $external_replacements = array(); 
 
 
  /** 
   * Constructor 
   * 
   * @return \WPSEO_Replace_Vars 
   */ 
  public function __construct() { 
  } 
 
 
  /** 
   * Setup the help texts and external replacements as statics so they will be available to all instances 
   */ 
  public static function setup_statics_once() { 
      if ( self::$help_texts === array() ) { 
          self::set_basic_help_texts(); 
          self::set_advanced_help_texts(); 
      } 
 
      if ( self::$external_replacements === array() ) { 
          /** 
           * Action: 'wpseo_register_extra_replacements' - Allows for registration of additional 
           * variables to replace 
           */ 
          do_action( 'wpseo_register_extra_replacements' ); 
      } 
  } 
 
 
  /** 
   * Register new replacement %%variables%% 
   * For use by other plugins/themes to register extra variables 
   * 
   * @see wpseo_register_var_replacement() for a usage example 
   * 
   * @param  string $var              The name of the variable to replace, i.e. '%%var%%' 
   *                                  - the surrounding %% are optional. 
   * @param  mixed  $replace_function Function or method to call to retrieve the replacement value for the variable 
   *                                  Uses the same format as add_filter/add_action function parameter and 
   *                                  should *return* the replacement value. DON'T echo it. 
   * @param  string $type             Type of variable: 'basic' or 'advanced', defaults to 'advanced'. 
   * @param  string $help_text        Help text to be added to the help tab for this variable. 
   * 
   * @return bool     Whether the replacement function was succesfully registered 
   */ 
  public static function register_replacement( $var, $replace_function, $type = 'advanced', $help_text = '' ) { 
      $success = false; 
 
      if ( is_string( $var ) && $var !== '' ) { 
          $var = self::remove_var_delimiter( $var ); 
 
          if ( preg_match( '`^[A-Z0-9_-]+$`i', $var ) === false ) { 
              trigger_error( __( 'A replacement variable can only contain alphanumeric characters, an underscore or a dash. Try renaming your variable.', 'wordpress-seo' ), E_USER_WARNING ); 
          } 
          elseif ( strpos( $var, 'cf_' ) === 0 || strpos( $var, 'ct_' ) === 0 ) { 
              trigger_error( __( 'A replacement variable can not start with "%%cf_" or "%%ct_" as these are reserved for the WPSEO standard variable variables for custom fields and custom taxonomies. Try making your variable name unique.', 'wordpress-seo' ), E_USER_WARNING ); 
          } 
          elseif ( ! method_exists( __CLASS__, 'retrieve_' . $var ) ) { 
              if ( ! isset( self::$external_replacements[ $var ] ) ) { 
                  self::$external_replacements[ $var ] = $replace_function; 
                  self::register_help_text( $type, $var, $help_text ); 
                  $success = true; 
              } 
              else { 
                  trigger_error( __( 'A replacement variable with the same name has already been registered. Try making your variable name unique.', 'wordpress-seo' ), E_USER_WARNING ); 
              } 
          } 
          else { 
              trigger_error( __( 'You cannot overrule a WPSEO standard variable replacement by registering a variable with the same name. Use the "wpseo_replacements" filter instead to adjust the replacement value.', 'wordpress-seo' ), E_USER_WARNING ); 
          } 
      } 
 
      return $success; 
  } 
 
 
  /** 
   * Replace `%%variable_placeholders%%` with their real value based on the current requested page/post/cpt/etc 
   * 
   * @param string $string the string to replace the variables in. 
   * @param array  $args   the object some of the replacement values might come from,  
   *                       could be a post, taxonomy or term. 
   * @param array  $omit   variables that should not be replaced by this function. 
   * 
   * @return string 
   */ 
  public function replace( $string, $args, $omit = array() ) { 
 
      $string = strip_tags( $string ); 
 
      // Let's see if we can bail super early. 
      if ( strpos( $string, '%%' ) === false ) { 
          return WPSEO_Utils::standardize_whitespace( $string ); 
      } 
 
      $args = (array) $args; 
      if ( isset( $args['post_content'] ) && ! empty( $args['post_content'] ) ) { 
          $args['post_content'] = WPSEO_Utils::strip_shortcode( $args['post_content'] ); 
      } 
      if ( isset( $args['post_excerpt'] ) && ! empty( $args['post_excerpt'] ) ) { 
          $args['post_excerpt'] = WPSEO_Utils::strip_shortcode( $args['post_excerpt'] ); 
      } 
      $this->args = (object) wp_parse_args( $args, $this->defaults ); 
 
      // Clean $omit array. 
      if ( is_array( $omit ) && $omit !== array() ) { 
          $omit = array_map( array( __CLASS__, 'remove_var_delimiter' ), $omit ); 
      } 
 
      $replacements = array(); 
      if ( preg_match_all( '`%%([^%]+(%%single)?)%%?`iu', $string, $matches ) ) { 
          $replacements = $this->set_up_replacements( $matches, $omit ); 
      } 
 
      /** 
       * Filter: 'wpseo_replacements' - Allow customization of the replacements before they are applied 
       * 
       * @api array $replacements The replacements 
       */ 
      $replacements = apply_filters( 'wpseo_replacements', $replacements ); 
 
      // Do the actual replacements. 
      if ( is_array( $replacements ) && $replacements !== array() ) { 
          $string = str_replace( array_keys( $replacements ), array_values( $replacements ), $string ); 
      } 
 
      /** 
       * Filter: 'wpseo_replacements_final' - Allow overruling of whether or not to remove placeholders 
       * which didn't yield a replacement 
       * 
       * @example <code>add_filter( 'wpseo_replacements_final', '__return_false' );</code> 
       * 
       * @api     bool $final 
       */ 
      if ( apply_filters( 'wpseo_replacements_final', true ) === true && ( isset( $matches[1] ) && is_array( $matches[1] ) ) ) { 
          // Remove non-replaced variables. 
          $remove = array_diff( $matches[1], $omit ); // Make sure the $omit variables do not get removed. 
          $remove = array_map( array( __CLASS__, 'add_var_delimiter' ), $remove ); 
          $string = str_replace( $remove, '', $string ); 
      } 
 
      // Undouble separators which have nothing between them, i.e. where a non-replaced variable was removed. 
      if ( isset( $replacements['%%sep%%'] ) && ( is_string( $replacements['%%sep%%'] ) && $replacements['%%sep%%'] !== '' ) ) { 
          $q_sep = preg_quote( $replacements['%%sep%%'], '`' ); 
          $string = preg_replace( '`' . $q_sep . '(?:\s*' . $q_sep . ')*`u', $replacements['%%sep%%'], $string ); 
      } 
 
      // Remove superfluous whitespace. 
      $string = WPSEO_Utils::standardize_whitespace( $string ); 
 
      return trim( $string ); 
  } 
 
 
  /** 
   * Retrieve the replacements for the variables found. 
   * 
   * @param array $matches variables found in the original string - regex result. 
   * @param array $omit    variables that should not be replaced by this function. 
   * 
   * @return array retrieved replacements - this might be a smaller array as some variables 
   *               may not yield a replacement in certain contexts. 
   */ 
  private function set_up_replacements( $matches, $omit ) { 
 
      $replacements = array(); 
 
      // @todo -> figure out a way to deal with external functions starting with cf_/ct_. 
      foreach ( $matches[1] as $k => $var ) { 
 
          // Don't set up replacements which should be omitted. 
          if ( in_array( $var, $omit, true ) ) { 
              continue; 
          } 
 
          // Deal with variable variable names first. 
          if ( strpos( $var, 'cf_' ) === 0 ) { 
              $replacement = $this->retrieve_cf_custom_field_name( $var ); 
          } 
          elseif ( strpos( $var, 'ct_desc_' ) === 0 ) { 
              $replacement = $this->retrieve_ct_desc_custom_tax_name( $var ); 
          } 
          elseif ( strpos( $var, 'ct_' ) === 0 ) { 
              $single = ( isset( $matches[2][ $k ] ) && $matches[2][ $k ] !== '' ) ? true : false; 
              $replacement = $this->retrieve_ct_custom_tax_name( $var, $single ); 
          } // Deal with non-variable variable names. 
          elseif ( method_exists( $this, 'retrieve_' . $var ) ) { 
              $method_name = 'retrieve_' . $var; 
              $replacement = $this->$method_name(); 
          } // Deal with externally defined variable names. 
          elseif ( isset( self::$external_replacements[ $var ] ) && ! is_null( self::$external_replacements[ $var ] ) ) { 
              $replacement = call_user_func( self::$external_replacements[ $var ], $var, $this->args ); 
          } 
 
          // Replacement retrievals can return null if no replacement can be determined, root those outs. 
          if ( isset( $replacement ) ) { 
              $var = self::add_var_delimiter( $var ); 
              $replacements[ $var ] = $replacement; 
          } 
          unset( $replacement, $single, $method_name ); 
      } 
 
      return $replacements; 
  } 
 
 
 
  /** *********************** BASIC VARIABLES ************************** */ 
 
  /** 
   * Retrieve the post/cpt categories (comma separated) for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_category() { 
      $replacement = null; 
 
      if ( ! empty( $this->args->ID ) ) { 
          $cat = $this->get_terms( $this->args->ID, 'category' ); 
          if ( $cat !== '' ) { 
              $replacement = $cat; 
          } 
      } 
 
      if ( ( ! isset( $replacement ) || $replacement === '' ) && ( isset( $this->args->cat_name ) && ! empty( $this->args->cat_name ) ) ) { 
          $replacement = $this->args->cat_name; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the category description for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_category_description() { 
      return $this->retrieve_term_description(); 
  } 
 
  /** 
   * Retrieve the date of the post/page/cpt for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_date() { 
      $replacement = null; 
 
      if ( $this->args->post_date !== '' ) { 
          $replacement = mysql2date( get_option( 'date_format' ), $this->args->post_date, true ); 
      } 
      else { 
          if ( get_query_var( 'day' ) && get_query_var( 'day' ) !== '' ) { 
              $replacement = get_the_date(); 
          } 
          else { 
              if ( single_month_title( ' ', false ) && single_month_title( ' ', false ) !== '' ) { 
                  $replacement = single_month_title( ' ', false ); 
              } 
              elseif ( get_query_var( 'year' ) !== '' ) { 
                  $replacement = get_query_var( 'year' ); 
              } 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt excerpt for use as replacement string. 
   * The excerpt will be auto-generated if it does not exist. 
   * 
   * @return string|null 
   */ 
  private function retrieve_excerpt() { 
      $replacement = null; 
 
      if ( ! empty( $this->args->ID ) ) { 
          if ( $this->args->post_excerpt !== '' ) { 
              $replacement = strip_tags( $this->args->post_excerpt ); 
          } 
          elseif ( $this->args->post_content !== '' ) { 
              $replacement = wp_html_excerpt( strip_shortcodes( $this->args->post_content ), 155 ); 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt excerpt for use as replacement string (without auto-generation). 
   * 
   * @return string|null 
   */ 
  private function retrieve_excerpt_only() { 
      $replacement = null; 
 
      if ( ! empty( $this->args->ID ) && $this->args->post_excerpt !== '' ) { 
          $replacement = strip_tags( $this->args->post_excerpt ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the title of the parent page of the current page/cpt for use as replacement string. 
   * Only applicable for hierarchical post types. 
   * 
   * @todo - check: shouldn't this use $this->args as well ? 
   * 
   * @return string|null 
   */ 
  private function retrieve_parent_title() { 
      $replacement = null; 
 
      if ( ! isset( $replacement ) && ( ( is_singular() || is_admin() ) && isset( $GLOBALS['post'] ) ) ) { 
          if ( isset( $GLOBALS['post']->post_parent ) && 0 !== $GLOBALS['post']->post_parent ) { 
              $replacement = get_the_title( $GLOBALS['post']->post_parent ); 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current search phrase for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_searchphrase() { 
      $replacement = null; 
 
      if ( ! isset( $replacement ) ) { 
          $search = get_query_var( 's' ); 
          if ( $search !== '' ) { 
              $replacement = esc_html( $search ); 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the separator for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_sep() { 
      return WPSEO_Utils::get_title_separator(); 
  } 
 
  /** 
   * Retrieve the site's tag line / description for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_sitedesc() { 
      static $replacement; 
 
      if ( ! isset( $replacement ) ) { 
          $description = trim( strip_tags( get_bloginfo( 'description' ) ) ); 
          if ( $description !== '' ) { 
              $replacement = $description; 
          } 
      } 
 
      return $replacement; 
  } 
 
 
  /** 
   * Retrieve the site's name for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_sitename() { 
      static $replacement; 
 
      if ( ! isset( $replacement ) ) { 
          $sitename = WPSEO_Utils::get_site_name(); 
          if ( $sitename !== '' ) { 
              $replacement = $sitename; 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current tag/tags for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_tag() { 
      $replacement = null; 
 
      if ( isset( $this->args->ID ) ) { 
          $tags = $this->get_terms( $this->args->ID, 'post_tag' ); 
          if ( $tags !== '' ) { 
              $replacement = $tags; 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the tag description for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_tag_description() { 
      return $this->retrieve_term_description(); 
  } 
 
  /** 
   * Retrieve the term description for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_term_description() { 
      $replacement = null; 
 
      if ( isset( $this->args->term_id ) && ! empty( $this->args->taxonomy ) ) { 
          $term_desc = get_term_field( 'description', $this->args->term_id, $this->args->taxonomy ); 
          if ( $term_desc !== '' ) { 
              $replacement = trim( strip_tags( $term_desc ) ); 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the term name for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_term_title() { 
      $replacement = null; 
 
      if ( ! empty( $this->args->taxonomy ) && ! empty( $this->args->name ) ) { 
          $replacement = $this->args->name; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the title of the post/page/cpt for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_title() { 
      $replacement = null; 
 
      if ( is_string( $this->args->post_title ) && $this->args->post_title !== '' ) { 
          $replacement = stripslashes( $this->args->post_title ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve primary category for use as replacement string. 
   * 
   * @return bool|int|null 
   */ 
  private function retrieve_primary_category() { 
      $primary_category = null; 
 
      if ( ! empty( $this->args->ID ) ) { 
          $wpseo_primary_category = new WPSEO_Primary_Term( 'category', $this->args->ID ); 
 
          $term_id = $wpseo_primary_category->get_primary_term(); 
          $term = get_term( $term_id ); 
 
          if ( ! is_wp_error( $term ) && ! empty( $term ) ) { 
              $primary_category = $term->name; 
          } 
      } 
 
      return $primary_category; 
  } 
 
 
  /** *********************** ADVANCED VARIABLES ************************** */ 
 
  /** 
   * Determine the page numbering of the current post/page/cpt 
   * 
   * @param string $request 'nr'|'max' - whether to return the page number or the max number of pages. 
   * 
   * @return int|null 
   */ 
  private function determine_pagenumbering( $request = 'nr' ) { 
      global $wp_query, $post; 
      $max_num_pages = null; 
      $page_number = null; 
 
      $max_num_pages = 1; 
 
      if ( ! is_singular() ) { 
          $page_number = get_query_var( 'paged' ); 
          if ( $page_number === 0 || $page_number === '' ) { 
              $page_number = 1; 
          } 
 
          if ( isset( $wp_query->max_num_pages ) && ( $wp_query->max_num_pages != '' && $wp_query->max_num_pages != 0 ) ) { 
              $max_num_pages = $wp_query->max_num_pages; 
          } 
      } 
      else { 
          $page_number = get_query_var( 'page' ); 
          if ( $page_number === 0 || $page_number === '' ) { 
              $page_number = 1; 
          } 
 
          if ( isset( $post->post_content ) ) { 
              $max_num_pages = ( substr_count( $post->post_content, '<!--nextpage-->' ) + 1 ); 
          } 
      } 
 
      $return = null; 
 
      switch ( $request ) { 
          case 'nr': 
              $return = $page_number; 
              break; 
          case 'max': 
              $return = $max_num_pages; 
              break; 
      } 
 
      return $return; 
  } 
 
 
  /** 
   * Determine the post type names for the current post/page/cpt 
   * 
   * @param string $request 'single'|'plural' - whether to return the single or plural form. 
   * 
   * @return string|null 
   */ 
  private function determine_pt_names( $request = 'single' ) { 
      global $wp_query; 
      $pt_single = null; 
      $pt_plural = null; 
 
      if ( isset( $wp_query->query_vars['post_type'] ) && ( ( is_string( $wp_query->query_vars['post_type'] ) && $wp_query->query_vars['post_type'] !== '' ) || ( is_array( $wp_query->query_vars['post_type'] ) && $wp_query->query_vars['post_type'] !== array() ) ) ) { 
          $post_type = $wp_query->query_vars['post_type']; 
      } 
      elseif ( isset( $this->args->post_type ) && ( is_string( $this->args->post_type ) && $this->args->post_type !== '' ) ) { 
          $post_type = $this->args->post_type; 
      } 
      else { 
          // Make it work in preview mode. 
          $post_type = $wp_query->get_queried_object()->post_type; 
      } 
 
      if ( is_array( $post_type ) ) { 
          $post_type = reset( $post_type ); 
      } 
 
      if ( $post_type !== '' ) { 
          $pt = get_post_type_object( $post_type ); 
          $pt_plural = $pt_single = $pt->name; 
          if ( isset( $pt->labels->singular_name ) ) { 
              $pt_single = $pt->labels->singular_name; 
          } 
          if ( isset( $pt->labels->name ) ) { 
              $pt_plural = $pt->labels->name; 
          } 
      } 
 
      $return = null; 
 
      switch ( $request ) { 
          case 'single': 
              $return = $pt_single; 
              break; 
          case 'plural': 
              $return = $pt_plural; 
              break; 
      } 
 
      return $return; 
  } 
 
  /** 
   * Retrieve the attachment caption for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_caption() { 
      return $this->retrieve_excerpt_only(); 
  } 
 
 
  /** 
   * Retrieve a post/page/cpt's custom field value for use as replacement string 
   * 
   * @param string $var The complete variable to replace which includes the name of 
   *                    the custom field which value is to be retrieved. 
   * 
   * @return string|null 
   */ 
  private function retrieve_cf_custom_field_name( $var ) { 
      global $post; 
      $replacement = null; 
 
      if ( is_string( $var ) && $var !== '' ) { 
          $field = substr( $var, 3 ); 
          if ( ( is_singular() || is_admin() ) && ( is_object( $post ) && isset( $post->ID ) ) ) { 
              $name = get_post_meta( $post->ID, $field, true ); 
              if ( $name !== '' ) { 
                  $replacement = $name; 
              } 
          } 
      } 
 
      return $replacement; 
  } 
 
 
  /** 
   * Retrieve a post/page/cpt's custom taxonomies for use as replacement string 
   * 
   * @param string $var    The complete variable to replace which includes the name of 
   *                       the custom taxonomy which value(s) is to be retrieved. 
   * @param bool   $single Whether to retrieve only the first or all values for the taxonomy. 
   * 
   * @return string|null 
   */ 
  private function retrieve_ct_custom_tax_name( $var, $single = false ) { 
      $replacement = null; 
 
      if ( ( is_string( $var ) && $var !== '' ) && ! empty( $this->args->ID ) ) { 
          $tax = substr( $var, 3 ); 
          $name = $this->get_terms( $this->args->ID, $tax, $single ); 
          if ( $name !== '' ) { 
              $replacement = $name; 
          } 
      } 
 
      return $replacement; 
  } 
 
 
  /** 
   * Retrieve a post/page/cpt's custom taxonomies description for use as replacement string 
   * 
   * @param string $var The complete variable to replace which includes the name of 
   *                    the custom taxonomy which description is to be retrieved. 
   * 
   * @return string|null 
   */ 
  private function retrieve_ct_desc_custom_tax_name( $var ) { 
      global $post; 
      $replacement = null; 
 
      if ( is_string( $var ) && $var !== '' ) { 
          $tax = substr( $var, 8 ); 
          if ( is_object( $post ) && isset( $post->ID ) ) { 
              $terms = get_the_terms( $post->ID, $tax ); 
              if ( is_array( $terms ) && $terms !== array() ) { 
                  $term = current( $terms ); 
                  $term_desc = get_term_field( 'description', $term->term_id, $tax ); 
                  if ( $term_desc !== '' ) { 
                      $replacement = trim( strip_tags( $term_desc ) ); 
                  } 
              } 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current date for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_currentdate() { 
      static $replacement; 
 
      if ( ! isset( $replacement ) ) { 
          $replacement = date_i18n( get_option( 'date_format' ) ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current day for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_currentday() { 
      static $replacement; 
 
      if ( ! isset( $replacement ) ) { 
          $replacement = date_i18n( 'j' ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current month for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_currentmonth() { 
      static $replacement; 
 
      if ( ! isset( $replacement ) ) { 
          $replacement = date_i18n( 'F' ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current time for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_currenttime() { 
      static $replacement; 
 
      if ( ! isset( $replacement ) ) { 
          $replacement = date_i18n( get_option( 'time_format' ) ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current year for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_currentyear() { 
      static $replacement; 
 
      if ( ! isset( $replacement ) ) { 
          $replacement = date_i18n( 'Y' ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt's focus keyword for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_focuskw() { 
      $replacement = null; 
 
      if ( ! empty( $this->args->ID ) ) { 
          $focus_kw = WPSEO_Meta::get_value( 'focuskw', $this->args->ID ); 
          if ( $focus_kw !== '' ) { 
              $replacement = $focus_kw; 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt ID for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_id() { 
      $replacement = null; 
 
      if ( ! empty( $this->args->ID ) ) { 
          $replacement = $this->args->ID; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt modified time for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_modified() { 
      $replacement = null; 
 
      if ( ! empty( $this->args->post_modified ) ) { 
          $replacement = mysql2date( get_option( 'date_format' ), $this->args->post_modified, true ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt author's "nice name" for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_name() { 
      $replacement = null; 
 
      $user_id = $this->retrieve_userid(); 
      $name = get_the_author_meta( 'display_name', $user_id ); 
      if ( $name !== '' ) { 
          $replacement = $name; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt author's users description for use as a replacement string. 
   * 
   * @return null|string 
   */ 
  private function retrieve_user_description() { 
      $replacement = null; 
 
      $user_id = $this->retrieve_userid(); 
      $description = get_the_author_meta( 'description', $user_id ); 
      if ( $description != '' ) { 
          $replacement = $description; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current page number with context (i.e. 'page 2 of 4') for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_page() { 
      $replacement = null; 
 
      $max = $this->determine_pagenumbering( 'max' ); 
      $nr = $this->determine_pagenumbering( 'nr' ); 
      $sep = $this->retrieve_sep(); 
 
      if ( $max > 1 && $nr > 1 ) { 
          $replacement = sprintf( $sep . ' ' . __( 'Page %1$d of %2$d', 'wordpress-seo' ), $nr, $max ); 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current page number for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_pagenumber() { 
      $replacement = null; 
 
      $nr = $this->determine_pagenumbering( 'nr' ); 
      if ( isset( $nr ) && $nr > 0 ) { 
          $replacement = (string) $nr; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the current page total for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_pagetotal() { 
      $replacement = null; 
 
      $max = $this->determine_pagenumbering( 'max' ); 
      if ( isset( $max ) && $max > 0 ) { 
          $replacement = (string) $max; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post type plural label for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_pt_plural() { 
      $replacement = null; 
 
      $name = $this->determine_pt_names( 'plural' ); 
      if ( isset( $name ) && $name !== '' ) { 
          $replacement = $name; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post type single label for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_pt_single() { 
      $replacement = null; 
 
      $name = $this->determine_pt_names( 'single' ); 
      if ( isset( $name ) && $name !== '' ) { 
          $replacement = $name; 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the slug which caused the 404 for use as replacement string. 
   * 
   * @return string|null 
   */ 
  private function retrieve_term404() { 
      $replacement = null; 
 
      if ( $this->args->term404 !== '' ) { 
          $replacement = sanitize_text_field( str_replace( '-', ' ', $this->args->term404 ) ); 
      } 
      else { 
          $error_request = get_query_var( 'pagename' ); 
          if ( $error_request !== '' ) { 
              $replacement = sanitize_text_field( str_replace( '-', ' ', $error_request ) ); 
          } 
          else { 
              $error_request = get_query_var( 'name' ); 
              if ( $error_request !== '' ) { 
                  $replacement = sanitize_text_field( str_replace( '-', ' ', $error_request ) ); 
              } 
          } 
      } 
 
      return $replacement; 
  } 
 
  /** 
   * Retrieve the post/page/cpt author's user id for use as replacement string. 
   * 
   * @return string 
   */ 
  private function retrieve_userid() { 
      $replacement = ! empty( $this->args->post_author ) ? $this->args->post_author : get_query_var( 'author' ); 
 
      return $replacement; 
  } 
 
 
 
  /** *********************** HELP TEXT RELATED ************************** */ 
 
  /** 
   * Create a variable help text table 
   * 
   * @param    string $type Either 'basic' or 'advanced'. 
   * 
   * @return    string            Help text table 
   */ 
  private static function create_variable_help_table( $type ) { 
      if ( ! in_array( $type, array( 'basic', 'advanced' ), true ) ) { 
          return ''; 
      } 
 
      $table = ' 
          <table class="yoast_help yoast-table-scrollable"> 
          <thead> 
              <tr> 
                  <th scope="col">' . esc_html__( 'Variable', 'wordpress-seo' ) . '</th> 
                  <th scope="col">' . esc_html__( 'Description', 'wordpress-seo' ) . '</th> 
              </tr> 
          </thead> 
          <tbody>'; 
 
      foreach ( self::$help_texts[ $type ] as $replace => $help_text ) { 
          $table .= ' 
              <tr> 
                  <td class="yoast-variable-name">%%' . esc_html( $replace ) . '%%</td> 
                  <td class="yoast-variable-desc">' . $help_text . '</td> 
              </tr>'; 
      } 
 
      $table .= ' 
          </tbody> 
          </table>'; 
 
      return $table; 
  } 
 
  /** 
   * Create the help text table for the basic variables for use in a help tab 
   * 
   * @return string 
   */ 
  public static function get_basic_help_texts() { 
      return self::create_variable_help_table( 'basic' ); 
  } 
 
 
  /** 
   * Create the help text table for the advanced variables for use in a help tab 
   * 
   * @return string 
   */ 
  public static function get_advanced_help_texts() { 
      return self::create_variable_help_table( 'advanced' ); 
  } 
 
 
  /** 
   * Set the help text for a user/plugin/theme defined extra variable. 
   * 
   * @param  string $type      Type of variable: 'basic' or 'advanced'. 
   * @param  string $replace   Variable to replace, i.e. '%%var%%'. 
   * @param  string $help_text The actual help text string. 
   */ 
  private static function register_help_text( $type, $replace, $help_text = '' ) { 
      if ( is_string( $replace ) && $replace !== '' ) { 
          $replace = self::remove_var_delimiter( $replace ); 
 
          if ( ( is_string( $type ) && in_array( $type, array( 
                      'basic',  
                      'advanced',  
 ), true ) ) && ( $replace !== '' && ! isset( self::$help_texts[ $type ][ $replace ] ) ) 
 ) { 
              self::$help_texts[ $type ][ $replace ] = $help_text; 
          } 
      } 
  } 
 
 
  /** 
   * Set/translate the help texts for the WPSEO standard basic variables. 
   */ 
  private static function set_basic_help_texts() { 
      self::$help_texts['basic'] = array( 
          'date' => __( 'Replaced with the date of the post/page', 'wordpress-seo' ),  
          'title' => __( 'Replaced with the title of the post/page', 'wordpress-seo' ),  
          'parent_title' => __( 'Replaced with the title of the parent page of the current page', 'wordpress-seo' ),  
          'sitename' => __( 'The site\'s name', 'wordpress-seo' ),  
          'sitedesc' => __( 'The site\'s tag line / description', 'wordpress-seo' ),  
          'excerpt' => __( 'Replaced with the post/page excerpt (or auto-generated if it does not exist)', 'wordpress-seo' ),  
          'excerpt_only' => __( 'Replaced with the post/page excerpt (without auto-generation)', 'wordpress-seo' ),  
          'tag' => __( 'Replaced with the current tag/tags', 'wordpress-seo' ),  
          'category' => __( 'Replaced with the post categories (comma separated)', 'wordpress-seo' ),  
          'primary_category' => __( 'Replaced with the primary category of the post/page', 'wordpress-seo' ),  
          'category_description' => __( 'Replaced with the category description', 'wordpress-seo' ),  
          'tag_description' => __( 'Replaced with the tag description', 'wordpress-seo' ),  
          'term_description' => __( 'Replaced with the term description', 'wordpress-seo' ),  
          'term_title' => __( 'Replaced with the term name', 'wordpress-seo' ),  
          'searchphrase' => __( 'Replaced with the current search phrase', 'wordpress-seo' ),  
          'sep' => sprintf( 
              /** translators: %s: wp_title() function */ 
              __( 'The separator defined in your theme\'s %s tag.', 'wordpress-seo' ),  
              '<code>wp_title()</code>' 
 ),  
 ); 
  } 
 
  /** 
   * Set/translate the help texts for the WPSEO standard advanced variables. 
   */ 
  private static function set_advanced_help_texts() { 
      self::$help_texts['advanced'] = array( 
          'pt_single' => __( 'Replaced with the post type single label', 'wordpress-seo' ),  
          'pt_plural' => __( 'Replaced with the post type plural label', 'wordpress-seo' ),  
          'modified' => __( 'Replaced with the post/page modified time', 'wordpress-seo' ),  
          'id' => __( 'Replaced with the post/page ID', 'wordpress-seo' ),  
          'name' => __( 'Replaced with the post/page author\'s \'nicename\'', 'wordpress-seo' ),  
          'user_description' => __( 'Replaced with the post/page author\'s \'Biographical Info\'', 'wordpress-seo' ),  
          'userid' => __( 'Replaced with the post/page author\'s userid', 'wordpress-seo' ),  
          'currenttime' => __( 'Replaced with the current time', 'wordpress-seo' ),  
          'currentdate' => __( 'Replaced with the current date', 'wordpress-seo' ),  
          'currentday' => __( 'Replaced with the current day', 'wordpress-seo' ),  
          'currentmonth' => __( 'Replaced with the current month', 'wordpress-seo' ),  
          'currentyear' => __( 'Replaced with the current year', 'wordpress-seo' ),  
          'page' => __( 'Replaced with the current page number with context (i.e. page 2 of 4)', 'wordpress-seo' ),  
          'pagetotal' => __( 'Replaced with the current page total', 'wordpress-seo' ),  
          'pagenumber' => __( 'Replaced with the current page number', 'wordpress-seo' ),  
          'caption' => __( 'Attachment caption', 'wordpress-seo' ),  
          'focuskw' => __( 'Replaced with the posts focus keyword', 'wordpress-seo' ),  
          'term404' => __( 'Replaced with the slug which caused the 404', 'wordpress-seo' ),  
          'cf_<custom-field-name>' => __( 'Replaced with a posts custom field value', 'wordpress-seo' ),  
          'ct_<custom-tax-name>' => __( 'Replaced with a posts custom taxonomies, comma separated.', 'wordpress-seo' ),  
          'ct_desc_<custom-tax-name>' => __( 'Replaced with a custom taxonomies description', 'wordpress-seo' ),  
 ); 
  } 
 
 
 
 
  /** *********************** GENERAL HELPER METHODS ************************** */ 
 
  /** 
   * Remove the '%%' delimiters from a variable string 
   * 
   * @param  string $string Variable string to be cleaned. 
   * 
   * @return string 
   */ 
  private static function remove_var_delimiter( $string ) { 
      return trim( $string, '%' ); 
  } 
 
  /** 
   * Add the '%%' delimiters to a variable string 
   * 
   * @param  string $string Variable string to be delimited. 
   * 
   * @return string 
   */ 
  private static function add_var_delimiter( $string ) { 
      return '%%' . $string . '%%'; 
  } 
 
  /** 
   * Retrieve a post's terms, comma delimited. 
   * 
   * @param int    $id            ID of the post to get the terms for. 
   * @param string $taxonomy      The taxonomy to get the terms for this post from. 
   * @param bool   $return_single If true, return the first term. 
   * 
   * @return string either a single term or a comma delimited string of terms. 
   */ 
  public function get_terms( $id, $taxonomy, $return_single = false ) { 
 
      $output = ''; 
 
      // If we're on a specific tag, category or taxonomy page, use that. 
      if ( is_category() || is_tag() || is_tax() ) { 
          $term = $GLOBALS['wp_query']->get_queried_object(); 
          $output = $term->name; 
      } 
      elseif ( ! empty( $id ) && ! empty( $taxonomy ) ) { 
          $terms = get_the_terms( $id, $taxonomy ); 
          if ( is_array( $terms ) && $terms !== array() ) { 
              foreach ( $terms as $term ) { 
                  if ( $return_single ) { 
                      $output = $term->name; 
                      break; 
                  } 
                  else { 
                      $output .= $term->name . ', '; 
                  } 
              } 
              $output = rtrim( trim( $output ), ', ' ); 
          } 
      } 
      unset( $terms, $term ); 
 
      /** 
       * Allows filtering of the terms list used to replace %%category%%, %%tag%% and %%ct_<custom-tax-name>%% variables 
       * 
       * @api    string    $output    Comma-delimited string containing the terms 
       */ 
      return apply_filters( 'wpseo_terms', $output ); 
  } 
} /** End of class WPSEO_Replace_Vars */ 
 
 
/** 
 * Setup the class statics when the file is first loaded 
 */ 
WPSEO_Replace_Vars::setup_statics_once();