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    <h3>Editing: class-wp-sitemaps-renderer.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php
/**
 * Sitemaps: WP_Sitemaps_Renderer class
 *
 * Responsible for rendering Sitemaps data to XML in accordance with sitemap protocol.
 *
 * @package WordPress
 * @subpackage Sitemaps
 * @since 5.5.0
 */

/**
 * Class WP_Sitemaps_Renderer
 *
 * @since 5.5.0
 */
#[AllowDynamicProperties]
class WP_Sitemaps_Renderer {
	/**
	 * XSL stylesheet for styling a sitemap for web browsers.
	 *
	 * @since 5.5.0
	 *
	 * @var string
	 */
	protected $stylesheet = '';

	/**
	 * XSL stylesheet for styling a sitemap for web browsers.
	 *
	 * @since 5.5.0
	 *
	 * @var string
	 */
	protected $stylesheet_index = '';

	/**
	 * WP_Sitemaps_Renderer constructor.
	 *
	 * @since 5.5.0
	 */
	public function __construct() {
		$stylesheet_url = $this-&gt;get_sitemap_stylesheet_url();

		if ( $stylesheet_url ) {
			$this-&gt;stylesheet = '&lt;?xml-stylesheet type=&quot;text/xsl&quot; href=&quot;' . esc_url( $stylesheet_url ) . '&quot; ?&gt;';
		}

		$stylesheet_index_url = $this-&gt;get_sitemap_index_stylesheet_url();

		if ( $stylesheet_index_url ) {
			$this-&gt;stylesheet_index = '&lt;?xml-stylesheet type=&quot;text/xsl&quot; href=&quot;' . esc_url( $stylesheet_index_url ) . '&quot; ?&gt;';
		}
	}

	/**
	 * Gets the URL for the sitemap stylesheet.
	 *
	 * @since 5.5.0
	 *
	 * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
	 *
	 * @return string The sitemap stylesheet URL.
	 */
	public function get_sitemap_stylesheet_url() {
		global $wp_rewrite;

		$sitemap_url = home_url( '/wp-sitemap.xsl' );

		if ( ! $wp_rewrite-&gt;using_permalinks() ) {
			$sitemap_url = home_url( '/?sitemap-stylesheet=sitemap' );
		}

		/**
		 * Filters the URL for the sitemap stylesheet.
		 *
		 * If a falsey value is returned, no stylesheet will be used and
		 * the &quot;raw&quot; XML of the sitemap will be displayed.
		 *
		 * @since 5.5.0
		 *
		 * @param string $sitemap_url Full URL for the sitemaps XSL file.
		 */
		return apply_filters( 'wp_sitemaps_stylesheet_url', $sitemap_url );
	}

	/**
	 * Gets the URL for the sitemap index stylesheet.
	 *
	 * @since 5.5.0
	 *
	 * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
	 *
	 * @return string The sitemap index stylesheet URL.
	 */
	public function get_sitemap_index_stylesheet_url() {
		global $wp_rewrite;

		$sitemap_url = home_url( '/wp-sitemap-index.xsl' );

		if ( ! $wp_rewrite-&gt;using_permalinks() ) {
			$sitemap_url = home_url( '/?sitemap-stylesheet=index' );
		}

		/**
		 * Filters the URL for the sitemap index stylesheet.
		 *
		 * If a falsey value is returned, no stylesheet will be used and
		 * the &quot;raw&quot; XML of the sitemap index will be displayed.
		 *
		 * @since 5.5.0
		 *
		 * @param string $sitemap_url Full URL for the sitemaps index XSL file.
		 */
		return apply_filters( 'wp_sitemaps_stylesheet_index_url', $sitemap_url );
	}

	/**
	 * Renders a sitemap index.
	 *
	 * @since 5.5.0
	 *
	 * @param array $sitemaps Array of sitemap URLs.
	 */
	public function render_index( $sitemaps ) {
		header( 'Content-Type: application/xml; charset=UTF-8' );

		$this-&gt;check_for_simple_xml_availability();

		$index_xml = $this-&gt;get_sitemap_index_xml( $sitemaps );

		if ( ! empty( $index_xml ) ) {
			// All output is escaped within get_sitemap_index_xml().
			echo $index_xml;
		}
	}

	/**
	 * Gets XML for a sitemap index.
	 *
	 * @since 5.5.0
	 *
	 * @param array $sitemaps Array of sitemap URLs.
	 * @return string|false A well-formed XML string for a sitemap index. False on error.
	 */
	public function get_sitemap_index_xml( $sitemaps ) {
		$sitemap_index = new SimpleXMLElement(
			sprintf(
				'%1$s%2$s%3$s',
				'&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; ?&gt;',
				$this-&gt;stylesheet_index,
				'&lt;sitemapindex xmlns=&quot;http://www.sitemaps.org/schemas/sitemap/0.9&quot; /&gt;'
			)
		);

		foreach ( $sitemaps as $entry ) {
			$sitemap = $sitemap_index-&gt;addChild( 'sitemap' );

			// Add each element as a child node to the &lt;sitemap&gt; entry.
			foreach ( $entry as $name =&gt; $value ) {
				if ( 'loc' === $name ) {
					$sitemap-&gt;addChild( $name, esc_url( $value ) );
				} elseif ( 'lastmod' === $name ) {
					$sitemap-&gt;addChild( $name, esc_xml( $value ) );
				} else {
					_doing_it_wrong(
						__METHOD__,
						sprintf(
							/* translators: %s: List of element names. */
							__( 'Fields other than %s are not currently supported for the sitemap index.' ),
							implode( ',', array( 'loc', 'lastmod' ) )
						),
						'5.5.0'
					);
				}
			}
		}

		return $sitemap_index-&gt;asXML();
	}

	/**
	 * Renders a sitemap.
	 *
	 * @since 5.5.0
	 *
	 * @param array $url_list Array of URLs for a sitemap.
	 */
	public function render_sitemap( $url_list ) {
		header( 'Content-Type: application/xml; charset=UTF-8' );

		$this-&gt;check_for_simple_xml_availability();

		$sitemap_xml = $this-&gt;get_sitemap_xml( $url_list );

		if ( ! empty( $sitemap_xml ) ) {
			// All output is escaped within get_sitemap_xml().
			echo $sitemap_xml;
		}
	}

	/**
	 * Gets XML for a sitemap.
	 *
	 * @since 5.5.0
	 *
	 * @param array $url_list Array of URLs for a sitemap.
	 * @return string|false A well-formed XML string for a sitemap index. False on error.
	 */
	public function get_sitemap_xml( $url_list ) {
		$urlset = new SimpleXMLElement(
			sprintf(
				'%1$s%2$s%3$s',
				'&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot; ?&gt;',
				$this-&gt;stylesheet,
				'&lt;urlset xmlns=&quot;http://www.sitemaps.org/schemas/sitemap/0.9&quot; /&gt;'
			)
		);

		foreach ( $url_list as $url_item ) {
			$url = $urlset-&gt;addChild( 'url' );

			// Add each element as a child node to the &lt;url&gt; entry.
			foreach ( $url_item as $name =&gt; $value ) {
				if ( 'loc' === $name ) {
					$url-&gt;addChild( $name, esc_url( $value ) );
				} elseif ( in_array( $name, array( 'lastmod', 'changefreq', 'priority' ), true ) ) {
					$url-&gt;addChild( $name, esc_xml( $value ) );
				} else {
					_doing_it_wrong(
						__METHOD__,
						sprintf(
							/* translators: %s: List of element names. */
							__( 'Fields other than %s are not currently supported for sitemaps.' ),
							implode( ',', array( 'loc', 'lastmod', 'changefreq', 'priority' ) )
						),
						'5.5.0'
					);
				}
			}
		}

		return $urlset-&gt;asXML();
	}

	/**
	 * Checks for the availability of the SimpleXML extension and errors if missing.
	 *
	 * @since 5.5.0
	 */
	private function check_for_simple_xml_availability() {
		if ( ! class_exists( 'SimpleXMLElement' ) ) {
			add_filter(
				'wp_die_handler',
				static function () {
					return '_xml_wp_die_handler';
				}
			);

			wp_die(
				sprintf(
					/* translators: %s: SimpleXML */
					esc_xml( __( 'Could not generate XML sitemap due to missing %s extension' ) ),
					'SimpleXML'
				),
				esc_xml( __( 'WordPress &amp;rsaquo; Error' ) ),
				array(
					'response' =&gt; 501, // &quot;Not implemented&quot;.
				)
			);
		}
	}
}
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