wp_robots()
- Since
- 5.7.0, 5.7.1
- Source
wp-includes/robots-template.php:20
Description
Gathers robots directives to include for the current context, using the 'wp_robots' filter. The directives are then sanitized, and the robots meta tag is output if there is at least one relevant directive.
Compatibility
- WordPress
- since 5.7.1
- 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.
Performance profile
How much work a call to wp_robots() 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
- Light
- Scaling
- Scales with input
- Instructions
- 11–19
- Plugin surface
- 1 hook
- Called by
- 1
Touches nothing outside its own arguments.
The body loops, so the work grows with how much data it finds.
Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 33.
Third-party callbacks on 'wp_robots' run inside this call, and their cost is not bounded by anything here.
1 place in core call this, so the cost is paid more often than your own code shows.
What it touches
- hookthird-party callbacks
apply_filters()called directly
Further down the call graph this can also reach option, cache, serialize, query and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.
What one call costs · 2 distinct outcomes
One number would be a lie: the work depends on which branch runs. These are every distinct cost wp_robots() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
empty($robots_strings) | 11–12 | apply_filters() |
!empty($robots_strings) | 18–19 | apply_filters(), esc_attr() |
Across PHP versions
| PHP | Compiled | Executed | Branches | Notes |
|---|---|---|---|---|
| 8.6-dev | 33 | 11–19 | 5 | |
| 8.5 | 33 | 11–19 | 5 | |
| 8.4 | 33 | 11–19 | 5 | 3 fewer instructions than PHP 8.3 |
| 8.3 | 36 | 11–22 | 5 | |
| 8.2 | 36 | 11–22 | 5 | |
| 8.1 | 36 | 11–22 | 5 | |
| 7.4 | 36 | 11–22 | 5 |
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.
Hooks and filters fired · 1
One hook fires while wp_robots() runs, in this order:
- apply_filters( wp_robots )filterline 32 (+12 into the body)
Filters the directives to be included in the 'robots' meta tag.
Uses · 2
- apply_filters()Calls the callback functions that have been added to a filter hook.
- esc_attr()Escaping for HTML attributes.
Used by · 1
- _default_wp_die_handler()Kills WordPress execution and displays HTML page with an error message.
Source code
function wp_robots() { /** * Filters the directives to be included in the 'robots' meta tag. * * The meta tag will only be included as necessary. * * @since 5.7.0 * * @param array $robots Associative array of directives. Every key must be the name of the directive, and the * corresponding value must either be a string to provide as value for the directive or a * boolean `true` if it is a boolean directive, i.e. without a value. */ $robots = apply_filters( 'wp_robots', array() ); $robots_strings = array(); foreach ( $robots as $directive => $value ) { if ( is_string( $value ) ) { // If a string value, include it as value for the directive. $robots_strings[] = "{$directive}:{$value}"; } elseif ( $value ) { // Otherwise, include the directive if it is truthy. $robots_strings[] = $directive; } } if ( empty( $robots_strings ) ) { return; } echo "<meta name='robots' content='" . esc_attr( implode( ', ', $robots_strings ) ) . "' />\n";}Changelog
Introduced in 5.7.0. 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 6.8.8 tag, from
src/wp-includes/robots-template.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.