Robots: Introduce Robots API.
This changeset introduces a filter-based Robots API, providing central control over the robots meta tag.
- Introduces
wp_robots() function which should be called anywhere a robots meta tag should be included.
- Introduces
wp_robots filter which allows adding or modifying directives for the robots meta tag. The wp_robots() function is entirely filter-based, i.e. if no filter is added to wp_robots, no directives will be present, and therefore the entire robots meta tag will be omitted.
- Introduces the following
wp_robots filter functions which replace similar existing functions that were manually rendering a robots meta tag:
wp_robots_noindex() replaces noindex(), which has been deprecated.
wp_robots_no_robots() replaces wp_no_robots(), which has been deprecated.
wp_robots_sensitive_page() replaces wp_sensitive_page_meta(), which has been deprecated. Its rendering of the referrer meta tag has been moved to another new function wp_strict_cross_origin_referrer().
Migration to the new functions is straightforward. For example, a call to add_action( 'wp_head', 'wp_no_robots' ) should be replaced with add_filter( 'wp_robots', 'wp_robots_no_robots' ).
Plugins and themes that render their own robots meta tags are encouraged to switch to rely on the wp_robots filter in order to use the central management layer now provided by WordPress core.
Props adamsilverstein, flixos90, timothyblynjacobs, westonruter.
See #51511.