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<?php |
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/** |
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* TOC Schema Module |
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* |
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* Generates JSON-LD SiteNavigationElement structured data and integrates with Yoast SEO schema graph. |
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* |
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* @package WPEXtra\Modules\Common\TOC |
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*/ |
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|
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namespace WPEXtra\Modules\Common\TOC; |
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|
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use WPEXtra\Helper; |
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|
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if ( ! defined( 'ABSPATH' ) ) { |
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exit; |
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} |
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|
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class Schema { |
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|
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/** |
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* Extracted heading nodes for current page request. |
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* |
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* @var array |
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*/ |
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private static $current_headings = array(); |
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|
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/** |
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* Initialize schema hooks. |
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*/ |
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public static function init() { |
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add_action( 'wp_footer', array( __CLASS__, 'output_json_ld' ), 20 ); |
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add_filter( 'wpseo_schema_graph', array( __CLASS__, 'integrate_yoast_schema' ), 10, 2 ); |
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} |
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|
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/** |
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* Store current headings for schema generation. |
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* |
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* @param array $headings |
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*/ |
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public static function set_headings( array $headings ) { |
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self::$current_headings = $headings; |
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} |
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|
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/** |
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* Flatten hierarchical tree into 1D list for schema items. |
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* |
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* @param array $tree |
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* @return array |
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*/ |
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private static function flatten_tree( array $tree ) { |
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$flat = array(); |
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foreach ( $tree as $item ) { |
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$flat[] = array( |
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'id' => $item['id'], |
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'title' => $item['title'], |
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); |
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if ( ! empty( $item['children'] ) ) { |
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$flat = array_merge( $flat, self::flatten_tree( $item['children'] ) ); |
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} |
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} |
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return $flat; |
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} |
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|
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/** |
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* Output JSON-LD SiteNavigationElement in wp_footer if Yoast is not active. |
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*/ |
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public static function output_json_ld() { |
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if ( empty( self::$current_headings ) || defined( 'WPSEO_VERSION' ) ) { |
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return; |
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} |
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|
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$permalink = get_permalink(); |
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if ( ! $permalink ) { |
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return; |
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} |
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|
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$items = self::flatten_tree( self::$current_headings ); |
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$elements = array(); |
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|
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foreach ( $items as $index => $item ) { |
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$elements[] = array( |
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'@context' => 'https://schema.org', |
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'@type' => 'SiteNavigationElement', |
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'id' => $permalink . '#' . $item['id'], |
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'name' => $item['title'], |
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'url' => $permalink . '#' . $item['id'], |
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); |
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} |
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|
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if ( ! empty( $elements ) ) { |
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echo "\n<!-- WP Extra Table of Contents Schema -->\n"; |
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echo '<script type="application/ld+json">' . wp_json_encode( $elements, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE ) . "</script>\n"; |
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} |
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} |
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|
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/** |
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* Integrate TOC items with Yoast SEO schema graph. |
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* |
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* @param array $graph |
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* @param object $context |
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* @return array |
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*/ |
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public static function integrate_yoast_schema( $graph, $context ) { |
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if ( empty( self::$current_headings ) ) { |
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return $graph; |
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} |
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|
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$permalink = get_permalink(); |
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if ( ! $permalink ) { |
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return $graph; |
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} |
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|
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$items = self::flatten_tree( self::$current_headings ); |
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|
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foreach ( $items as $item ) { |
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$graph[] = array( |
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'@context' => 'https://schema.org', |
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'@type' => 'SiteNavigationElement', |
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'@id' => $permalink . '#' . $item['id'], |
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'name' => $item['title'], |
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'url' => $permalink . '#' . $item['id'], |
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); |
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} |
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|
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return $graph; |
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} |
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} |
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|
