redirect_canonical( string $requested_url = null, bool $do_redirect = true ): string|void

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$requested_urlstringoptional

The URL that was requested, used to figure if redirect is needed.Default: null

$do_redirectbooloptional

Redirect to the new URL.Default: true

Return value

string|void

The string of the URL, if redirect needed.

Performance profile

How much work a call to redirect_canonical() 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

Heavy

Reaches the database via get_post().

Scaling

Constant

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

Instructions

17–270

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 1817.

Plugin surface

2 hooks

Third-party callbacks on 'wp_signup_location', 'redirect_canonical' 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

• querycontent queryget_post()called directly
• optionoption read or writeget_option()called directly
• hookthird-party callbacksapply_filters()called directly
• regexregular expression over the whole inputpreg_replace_callback()called directly
• cacheobject cachewp_cache_get()one call below redirect_canonical()
• serializeserialisationmaybe_unserialize()one call below redirect_canonical()

Further down the call graph this can also reach transient. That is the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 38 distinct outcomes

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

This body has more branch combinations than are worth enumerating, so the table covers the outcomes found first rather than every one that exists.

Hooks and filters fired · 2

2 hooks fire while redirect_canonical() runs, in this order:

1. 1
   apply_filters( wp_signup_location )filterline 540 (+498 into the body)

   Filters the Multisite sign up URL.

2. 2
   apply_filters( redirect_canonical )filterline 821 (+779 into the body)

   Filters the canonical redirect URL.

Uses · 70

• is_preview()Determines whether the query is for a post or page preview.
• get_query_var()Retrieves the value of a query variable in the WP_Query class.
• get_post_status()Retrieves the post status based on the post ID.
• wp_verify_nonce()Verifies that a correct security nonce was used with time limit.
• is_admin()Determines whether the current request is for an administrative interface page.
• is_search()Determines whether the query is for a search.
• is_trackback()Determines whether the query is for a trackback endpoint call.
• is_favicon()Is the query for the favicon.ico file?
• iis7_supports_permalinks()Checks if IIS 7+ supports pretty permalinks.
• is_ssl()Determines if SSL is used.
• remove_query_arg()Removes an item or items from a query string.
• is_feed()Determines whether the query is for a feed.

Used by · 1

• redirect_canonical()Redirects incoming links to the proper URL based on the site url.

Source code

View on Trac ↗View on GitHub ↗

42function redirect_canonical( $requested_url = null, $do_redirect = true ) {43	global $wp_rewrite, $is_IIS, $wp_query, $wpdb, $wp;44 45	if ( isset( $_SERVER['REQUEST_METHOD'] ) && ! in_array( strtoupper( $_SERVER['REQUEST_METHOD'] ), array( 'GET', 'HEAD' ), true ) ) {46		return;47	}48 49	/*50	 * If we're not in wp-admin and the post has been published and preview nonce51	 * is non-existent or invalid then no need for preview in query.52	 */53	if ( is_preview() && get_query_var( 'p' ) && 'publish' === get_post_status( get_query_var( 'p' ) ) ) {54		if ( ! isset( $_GET['preview_id'] )55			|| ! isset( $_GET['preview_nonce'] )56			|| ! wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . (int) $_GET['preview_id'] )57		) {58			$wp_query->is_preview = false;59		}60	}61 62	if ( is_admin() || is_search() || is_preview() || is_trackback() || is_favicon()63		|| ( $is_IIS && ! iis7_supports_permalinks() )64	) {65		return;66	}67 68	if ( ! $requested_url && isset( $_SERVER['HTTP_HOST'] ) ) {69		// Build the URL in the address bar.70		$requested_url  = is_ssl() ? 'https://' : 'http://';71		$requested_url .= $_SERVER['HTTP_HOST'];72		$requested_url .= $_SERVER['REQUEST_URI'];73	}74 75	$original = parse_url( $requested_url );76	if ( false === $original ) {77		return;78	}79 80	$redirect     = $original;81	$redirect_url = false;82	$redirect_obj = false;83 84	// Notice fixing.85	if ( ! isset( $redirect['path'] ) ) {86		$redirect['path'] = '';87	}88	if ( ! isset( $redirect['query'] ) ) {89		$redirect['query'] = '';90	}91 92	/*93	 * If the original URL ended with non-breaking spaces, they were almost94	 * certainly inserted by accident. Let's remove them, so the reader doesn't95	 * see a 404 error with no obvious cause.96	 */97	$redirect['path'] = preg_replace( '|(%C2%A0)+$|i', '', $redirect['path'] );98 99	// It's not a preview, so remove it from URL.100	if ( get_query_var( 'preview' ) ) {101		$redirect['query'] = remove_query_arg( 'preview', $redirect['query'] );102	}103 104	$post_id = get_query_var( 'p' );105 106	if ( is_feed() && $post_id ) {107		$redirect_url = get_post_comments_feed_link( $post_id, get_query_var( 'feed' ) );108		$redirect_obj = get_post( $post_id );109 110		if ( $redirect_url ) {111			$redirect['query'] = _remove_qs_args_if_not_in_url(112				$redirect['query'],113				array( 'p', 'page_id', 'attachment_id', 'pagename', 'name', 'post_type', 'feed' ),114				$redirect_url115			);116 117			$redirect['path'] = parse_url( $redirect_url, PHP_URL_PATH );118		}119	}120 121	if ( is_singular() && $wp_query->post_count < 1 && $post_id ) {

Changelog

Introduced in 2.3.0. One change between 6.7.7 and 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 6.7.7 tag, from src/wp-includes/canonical.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.