wp_get_canonical_url() │ WP 4.6.0

Gets the canonical URL of a post.

For pagination pages, a separate link is created. For example, for the comment pagination page of a post, it will look like this: http://example.com/postname/comment-page-2.

Uses: get_permalink()
Used By: rel_canonical()
1 time — 0.000338 sec (fast) | 50000 times — 3.05 sec (fast) | PHP 7.0.8, WP 4.6
Hooks from the function

Returns

String|false. Canonical URL or false if the post does not exist or has not been published yet.

Usage

wp_get_canonical_url( $post );
$post(integer/WP_Post)
ID or post object.
Default: null (current post)

Examples

0

#1 Output the canonical URL of post 803 

echo wp_get_canonical_url( 803 );
// outputs: http://example.com/post-name/

Changelog

Since 4.6.0 Introduced.

wp_get_canonical_url() code WP 7.0

wp-includes/link-template.php 
function wp_get_canonical_url( $post = null ) {
	$post = get_post( $post );

	if ( ! $post ) {
		return false;
	}

	if ( 'publish' !== get_post_status( $post ) ) {
		return false;
	}

	$canonical_url = get_permalink( $post );

	// If a canonical is being generated for the current page, make sure it has pagination if needed.
	if ( get_queried_object_id() === $post->ID ) {
		$page = get_query_var( 'page', 0 );
		if ( $page >= 2 ) {
			if ( ! get_option( 'permalink_structure' ) ) {
				$canonical_url = add_query_arg( 'page', $page, $canonical_url );
			} else {
				$canonical_url = trailingslashit( $canonical_url ) . user_trailingslashit( $page, 'single_paged' );
			}
		}

		$cpage = get_query_var( 'cpage', 0 );
		if ( $cpage ) {
			$canonical_url = get_comments_pagenum_link( $cpage );
		}
	}

	/**
	 * Filters the canonical URL for a post.
	 *
	 * @since 4.6.0
	 *
	 * @param string  $canonical_url The post's canonical URL.
	 * @param WP_Post $post          Post object.
	 */
	return apply_filters( 'get_canonical_url', $canonical_url, $post );
}

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