add_rewrite_tag

Add a new rewrite tag (like %postname%).

Description

add_rewrite_tag( (string) $tag, (string) $regex, (string) $query = '' ); 

The $query parameter is optional. If it is omitted you must ensure that you call this on, or before, the hook. This is because $query defaults to $tag=,, and for this to work a new query var has to be added.

Parameters (3)

0. $tag (string)
Name of the new rewrite tag.
1. $regex (string)
Regular expression to substitute the tag for in rewrite rules.
2. $query — Optional. (string) => ''
String to append to the rewritten query. Must end in =.. Default empty.

Usage

  1. if ( !function_exists( 'add_rewrite_tag' ) ) { 
  2.     require_once ABSPATH . WPINC . '/rewrite.php'; 
  3. } 
  4.   
  5. // Name of the new rewrite tag. 
  6. $tag = ''; 
  7.   
  8. // Regular expression to substitute the tag for in rewrite rules. 
  9. $regex = ''; 
  10.   
  11. // Optional. String to append to the rewritten query. Must end in '='. Default empty. 
  12. $query = ''; 
  13.   
  14. // NOTICE! Understand what this does before running. 
  15. $result = add_rewrite_tag($tag, $regex, $query); 
  16.     

Defined (1)

The function is defined in the following location(s).

/wp-includes/rewrite.php  
  1. function add_rewrite_tag( $tag, $regex, $query = '' ) { 
  2.     // validate the tag's name 
  3.     if ( strlen( $tag ) < 3 || $tag[0] != '%' || $tag[ strlen($tag) - 1 ] != '%' ) 
  4.         return; 
  5.  
  6.     global $wp_rewrite, $wp; 
  7.  
  8.     if ( empty( $query ) ) { 
  9.         $qv = trim( $tag, '%' ); 
  10.         $wp->add_query_var( $qv ); 
  11.         $query = $qv . '='; 
  12.     } 
  13.  
  14.     $wp_rewrite->add_rewrite_tag( $tag, $regex, $query ); 
  15. }