diff options
Diffstat (limited to 'plugins/jetpack/_inc/lib/class-jetpack-podcast-feed-locator.php')
| -rw-r--r-- | plugins/jetpack/_inc/lib/class-jetpack-podcast-feed-locator.php | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/plugins/jetpack/_inc/lib/class-jetpack-podcast-feed-locator.php b/plugins/jetpack/_inc/lib/class-jetpack-podcast-feed-locator.php new file mode 100644 index 00000000..82a2a766 --- /dev/null +++ b/plugins/jetpack/_inc/lib/class-jetpack-podcast-feed-locator.php @@ -0,0 +1,113 @@ +<?php +/** + * Extension of the SimplePie_Locator class, to detect podcast feeds + * + * @package automattic/jetpack + */ + +/** + * 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_File $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 ) && $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; + } + + $feed_dom = $this->safely_load_xml( $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 restulting DOM document or `false` if there is an error. + */ + private function safely_load_xml( $xml ) { + $disable_entity_loader = PHP_VERSION_ID < 80000; + + if ( $disable_entity_loader && ! function_exists( 'libxml_disable_entity_loader' ) ) { + return false; + } + + 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; + } + +} + |