add_rewrite_tag( string $tag, string $regex, string $query = '' )
- Since
- 2.1.0
- Source
wp-includes/rewrite.php:162
Description
The $query parameter is optional. If it is omitted you must ensure that you call this on, or before, the 'init' hook. This is because $query defaults to $tag=, and for this to work a new query var has to be added.
Compatibility
- WordPress
- since 2.1.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$tagstring- Name of the new rewrite tag.
$regexstring- Regular expression to substitute the tag for in rewrite rules.
$querystringoptional- String to append to the rewritten query. Must end in '='. Default empty.Default:
''
Performance profile
How much work a call to add_rewrite_tag() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.
- Cost class
- Trivial
- Scaling
- Constant
- Instructions
- 7–30
- Plugin surface
- None
- Called by
- 3
Touches nothing outside its own arguments.
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 31.
Nothing here hands control to plugin code.
3 places in core call this, so the cost is paid more often than your own code shows.
What one call costs · 3 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost add_rewrite_tag() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 7–15 | none |
!empty($query) | 24 | ->add_rewrite_tag() |
empty($query) | 30 | ->add_query_var(), ->add_rewrite_tag() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 31 | 7–30 | 4 | |
| 8.5 | 31 | 7–30 | 4 | |
| 8.4 | 31 | 7–30 | 4 | 4 fewer instructions than PHP 8.3 |
| 8.3 | 35 | 7–34 | 4 | |
| 8.2 | 35 | 7–34 | 4 | |
| 8.1 | 35 | 7–34 | 4 | |
| 7.4 | 35 | 7–34 | 4 |
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Used by · 3
- WP_Post_Type::add_rewrite_rules()Adds the necessary rewrite rules for the post type.
- WP_Sitemaps::register_rewrites()Registers sitemap rewrite tags and routing rules.
- WP_Taxonomy::add_rewrite_rules()Adds the necessary rewrite rules for the taxonomy.
Source code
function add_rewrite_tag( $tag, $regex, $query = '' ) { // Validate the tag's name. if ( strlen( $tag ) < 3 || '%' !== $tag[0] || '%' !== $tag[ strlen( $tag ) - 1 ] ) { return; } global $wp_rewrite, $wp; if ( empty( $query ) ) { $qv = trim( $tag, '%' ); $wp->add_query_var( $qv ); $query = $qv . '='; } $wp_rewrite->add_rewrite_tag( $tag, $regex, $query );}Changelog
Introduced in 2.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 7.0.4 tag, from
src/wp-includes/rewrite.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it. - Corrections
- Something wrong on this page? Report it and it gets fixed in the next regeneration.