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wp-content/plugins/jetpack/_inc/lib/class-jetpack-podcast-feed-locator.php

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+<?php
+/**
+ * Extension of the SimplePie\Locator class, to detect podcast feeds
+ *
+ * @package automattic/jetpack
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit( 0 );
+}
+
+/**
+ * Class Jetpack_Podcast_Feed_Locator
+ */
+class Jetpack_Podcast_Feed_Locator extends SimplePie\Locator {
+
+	/**
+	 * Overrides the locator is_feed function to check for
+	 * appropriate podcast elements.
+	 *
+	 * @param SimplePie\HTTP\Response $file The file being checked.
+	 * @param boolean                 $check_html Adds text/html to the mimetypes checked.
+	 */
+	public function is_feed( $file, $check_html = false ) {
+		return parent::is_feed( $file, $check_html ) &&
+			$file instanceof SimplePie\File &&
+			$this->is_podcast_feed( $file );
+	}
+
+	/**
+	 * Checks the contents of the file for elements that make
+	 * it a podcast feed.
+	 *
+	 * @param SimplePie\File $file The file being checked.
+	 */
+	private function is_podcast_feed( $file ) {
+		// If we can't read the DOM assume it's a podcast feed, we'll work
+		// it out later.
+		if ( ! class_exists( 'DOMDocument' ) ) {
+			return true;
+		}
+
+		// @todo Drop is_callable check once Simple gets the SimplePie update that came with WordPress 6.9.
+		if ( is_callable( array( $file, 'get_body_content' ) ) ) {
+			$feed_dom = $this->safely_load_xml( $file->get_body_content() );
+		} else {
+			// @phan-suppress-next-line PhanDeprecatedProperty -- For compatibility only.
+			$feed_dom = $this->safely_load_xml( (string) $file->body );
+		}
+
+		// Do this as either/or but prioritise the itunes namespace. It's pretty likely
+		// that it's a podcast feed we've found if that namespace is present.
+		return $feed_dom && $this->has_itunes_ns( $feed_dom ) && $this->has_audio_enclosures( $feed_dom );
+	}
+
+	/**
+	 * Safely loads an XML file
+	 *
+	 * @param string $xml A string of XML to load.
+	 * @return DOMDocument|false A resulting DOM document or `false` if there is an error.
+	 */
+	private function safely_load_xml( $xml ) {
+		if ( empty( $xml ) ) {
+			return false;
+		}
+
+		$disable_entity_loader = PHP_VERSION_ID < 80000;
+
+		if ( $disable_entity_loader ) {
+			// This function has been deprecated in PHP 8.0 because in libxml 2.9.0, external entity loading
+			// is disabled by default, so this function is no longer needed to protect against XXE attacks.
+			// phpcs:ignore Generic.PHP.DeprecatedFunctions.Deprecated, PHPCompatibility.FunctionUse.RemovedFunctions.libxml_disable_entity_loaderDeprecated
+			$loader = libxml_disable_entity_loader( true );
+		}
+
+		$errors = libxml_use_internal_errors( true );
+
+		$return = new DOMDocument();
+		if ( ! $return->loadXML( $xml ) ) {
+			return false;
+		}
+
+		libxml_use_internal_errors( $errors );
+
+		if ( $disable_entity_loader && isset( $loader ) ) {
+			// phpcs:ignore Generic.PHP.DeprecatedFunctions.Deprecated, PHPCompatibility.FunctionUse.RemovedFunctions.libxml_disable_entity_loaderDeprecated
+			libxml_disable_entity_loader( $loader );
+		}
+
+		return $return;
+	}
+
+	/**
+	 * Checks the RSS feed for the presence of the itunes podcast namespace.
+	 * It's pretty loose and just checks the URI for itunes.com
+	 *
+	 * @param DOMDocument $dom The XML document to check.
+	 * @return boolean Whether the itunes namespace is defined.
+	 */
+	private function has_itunes_ns( $dom ) {
+		$xpath = new DOMXPath( $dom );
+		foreach ( $xpath->query( 'namespace::*' ) as $node ) {
+			// phpcs:disable WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
+			// nodeValue is not valid, but it's part of the DOM API that we don't control.
+			if ( strstr( $node->nodeValue, 'itunes.com' ) ) {
+				return true;
+			}
+			// phpcs:enable
+		}
+		return false;
+	}
+
+	/**
+	 * Checks the RSS feed for the presence of enclosures with an audio mimetype.
+	 *
+	 * @param DOMDocument $dom The XML document to check.
+	 * @return boolean Whether enclosures were found.
+	 */
+	private function has_audio_enclosures( $dom ) {
+		$xpath      = new DOMXPath( $dom );
+		$enclosures = $xpath->query( "//enclosure[starts-with(@type,'audio/')]" );
+		return ! $enclosures ? false : $enclosures->length > 0;
+	}
+}