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