WP::handle_404()

Description

Compatibility

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::handle_404() 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

Touches nothing outside its own arguments.

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

9–75

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 120.

Plugin surface

1 hook

Third-party callbacks on 'pre_handle_404' run inside this call, and their cost is not bounded by anything here.

Called by

1

1 place in core call this, so the cost is paid more often than your own code shows.

What it touches

• hookthird-party callbacksapply_filters()called directly

Further down the call graph this can also reach query, cache, serialize, option 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 · 92 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP::handle_404() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 1

One hook fires while WP::handle_404() runs, in this order:

1. 1
   apply_filters( pre_handle_404 )filterline 738 (+14 into the body)

   Filters whether to short-circuit default header status handling.

Uses · 21

• apply_filters()Calls the callback functions that have been added to a filter hook.
• is_404()Determines whether the query has resulted in a 404 (returns no results).
• is_admin()Determines whether the current request is for an administrative interface page.
• is_robots()Is the query for the robots.txt file?
• is_favicon()Is the query for the favicon.ico file?
• is_singular()Determines whether the query is for an existing single post of any post type (post, attachment, page, custom post types).
• str_contains()Polyfill for `str_contains()` function added in PHP 8.0.
• is_paged()Determines whether the query is for a paged result and not for the first page.
• get_query_var()Retrieves the value of a query variable in the WP_Query class.
• is_author()Determines whether the query is for an existing author archive page.
• is_user_member_of_blog()Finds out whether a user is a member of a given blog.
• is_tag()Determines whether the query is for an existing tag archive page.

Used by · 1

• WP::main()Sets up all of the variables required by the WordPress environment.

Source code

View on Trac ↗View on GitHub ↗

724	public function handle_404() {725		global $wp_query;726 727		/**728		 * Filters whether to short-circuit default header status handling.729		 *730		 * Returning a non-false value from the filter will short-circuit the handling731		 * and return early.732		 *733		 * @since 4.5.0734		 *735		 * @param bool     $preempt  Whether to short-circuit default header status handling. Default false.736		 * @param WP_Query $wp_query WordPress Query object.737		 */738		if ( false !== apply_filters( 'pre_handle_404', false, $wp_query ) ) {739			return;740		}741 742		// If we've already issued a 404, bail.743		if ( is_404() ) {744			return;745		}746 747		$set_404 = true;748 749		// Never 404 for the admin, robots, or favicon.750		if ( is_admin() || is_robots() || is_favicon() ) {751			$set_404 = false;752 753			// If posts were found, check for paged content.754		} elseif ( $wp_query->posts ) {755			$content_found = true;756 757			if ( is_singular() ) {758				$post = $wp_query->post ?? null;759				$next = '<!--nextpage-->';760 761				// Check for paged content that exceeds the max number of pages.762				if ( $post && ! empty( $this->query_vars['page'] ) ) {763					// Check if content is actually intended to be paged.764					if ( str_contains( $post->post_content, $next ) ) {765						$page          = trim( $this->query_vars['page'], '/' );766						$content_found = (int) $page <= ( substr_count( $post->post_content, $next ) + 1 );767					} else {768						$content_found = false;769					}770				}771			}772 773			// The posts page does not support the <!--nextpage--> pagination.774			if ( $wp_query->is_posts_page && ! empty( $this->query_vars['page'] ) ) {775				$content_found = false;776			}777 778			if ( $content_found ) {779				$set_404 = false;780			}781 782			// We will 404 for paged queries, as no posts were found.783		} elseif ( ! is_paged() ) {784			$author = get_query_var( 'author' );785 786			// Don't 404 for authors without posts as long as they matched an author on this site.787			if ( is_author() && is_numeric( $author ) && $author > 0 && is_user_member_of_blog( $author )788				// Don't 404 for these queries if they matched an object.789				|| ( is_tag() || is_category() || is_tax() || is_post_type_archive() ) && get_queried_object()790				// Don't 404 for these queries either.791				|| is_home() || is_search() || is_feed()792			) {793				$set_404 = false;794			}795		}796 797		if ( $set_404 ) {798			// Guess it's time to 404.799			$wp_query->set_404();800			status_header( 404 );801			nocache_headers();802		} else {803			status_header( 200 );

Changelog

Introduced in 2.0.0. Unchanged from 6.7.7 through 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/class-wp.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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