canonical-urls.php
| 1 | <?php |
| 2 | /** |
| 3 | * Module Name: Canonical URLs |
| 4 | * Module Description: Add canonical URL tags to archive pages to prevent duplicate content in search engines. |
| 5 | * Sort Order: 36 |
| 6 | * First Introduced: 15.6 |
| 7 | * Requires Connection: No |
| 8 | * Requires User Connection: No |
| 9 | * Auto Activate: No |
| 10 | * Module Tags: Traffic |
| 11 | * Feature: Traffic |
| 12 | * Additional Search Queries: canonical, seo, duplicate content, woocommerce, archive |
| 13 | * |
| 14 | * @package automattic/jetpack |
| 15 | */ |
| 16 | |
| 17 | if ( ! defined( 'ABSPATH' ) ) { |
| 18 | exit( 0 ); |
| 19 | } |
| 20 | |
| 21 | // Disable canonical URL output when a conflicting SEO plugin is active. |
| 22 | add_filter( 'jetpack_disable_canonical_urls', 'jetpack_canonical_urls_check_conflicts' ); |
| 23 | |
| 24 | /** |
| 25 | * Can be used to prevent the Canonical URLs module from outputting canonical tags. |
| 26 | * |
| 27 | * @module canonical-urls |
| 28 | * |
| 29 | * @since 15.6 |
| 30 | * |
| 31 | * @param bool $disabled Whether canonical URL output is disabled. Defaults to false. |
| 32 | */ |
| 33 | if ( ! apply_filters( 'jetpack_disable_canonical_urls', false ) ) { |
| 34 | require_once __DIR__ . '/canonical-urls/class-jetpack-canonical-urls-resolver.php'; |
| 35 | add_action( 'wp_head', 'jetpack_canonical_urls_output_tag' ); |
| 36 | } |
| 37 | |
| 38 | /** |
| 39 | * Check if a conflicting SEO plugin is active and disable canonical URL output. |
| 40 | * |
| 41 | * @since 15.6 |
| 42 | * |
| 43 | * @param bool $disabled Whether canonical URL output is already disabled. |
| 44 | * @return bool Whether canonical URL output should be disabled. |
| 45 | */ |
| 46 | function jetpack_canonical_urls_check_conflicts( $disabled ) { |
| 47 | if ( $disabled ) { |
| 48 | return $disabled; |
| 49 | } |
| 50 | |
| 51 | $conflicting_plugins = array( |
| 52 | 'wordpress-seo/wp-seo.php', |
| 53 | 'wordpress-seo-premium/wp-seo-premium.php', |
| 54 | 'all-in-one-seo-pack/all_in_one_seo_pack.php', |
| 55 | 'all-in-one-seo-pack-pro/all_in_one_seo_pack.php', |
| 56 | 'seo-by-rank-math/rank-math.php', |
| 57 | 'autodescription/autodescription.php', |
| 58 | 'slim-seo/slim-seo.php', |
| 59 | 'wp-seopress/seopress.php', |
| 60 | 'wp-seopress-pro/seopress-pro.php', |
| 61 | 'seo-key/seo-key.php', |
| 62 | 'seo-key-pro/seo-key.php', |
| 63 | ); |
| 64 | |
| 65 | foreach ( $conflicting_plugins as $plugin ) { |
| 66 | if ( Jetpack::is_plugin_active( $plugin ) ) { |
| 67 | return true; |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | return $disabled; |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Output the canonical link tag for non-singular pages. |
| 76 | * |
| 77 | * WordPress core handles singular posts/pages via rel_canonical(), |
| 78 | * so this function only outputs canonical tags for archive pages. |
| 79 | * |
| 80 | * @since 15.6 |
| 81 | */ |
| 82 | function jetpack_canonical_urls_output_tag() { |
| 83 | if ( is_singular() ) { |
| 84 | return; |
| 85 | } |
| 86 | |
| 87 | $url = Jetpack_Canonical_Urls_Resolver::get_canonical_url(); |
| 88 | |
| 89 | if ( ! empty( $url ) ) { |
| 90 | echo '<link rel="canonical" href="' . esc_url( $url ) . '" />' . "\n"; |
| 91 | } |
| 92 | } |
| 93 |