class-jetpack-podcast-feed-locator.php — Jetpack – WP Security, Backup, Speed, & Growth 15.3.2

jetpack / _inc / lib / class-jetpack-podcast-feed-locator.php

jetpack / _inc / lib Last commit date

class-jetpack-podcast-feed-locator.php

116 lines

1	<?php
2	/**
3	* Extension of the SimplePie\Locator class, to detect podcast feeds
4	*
5	* @package automattic/jetpack
6	*/
7
8	if ( ! defined( 'ABSPATH' ) ) {
9	exit( 0 );
10	}
11
12	/**
13	* Class Jetpack_Podcast_Feed_Locator
14	*/
15	class Jetpack_Podcast_Feed_Locator extends SimplePie\Locator {
16	/**
17	* Overrides the locator is_feed function to check for
18	* appropriate podcast elements.
19	*
20	* @param SimplePie\File $file The file being checked.
21	* @param boolean $check_html Adds text/html to the mimetypes checked.
22	*/
23	public function is_feed( $file, $check_html = false ) {
24	return parent::is_feed( $file, $check_html ) && $this->is_podcast_feed( $file );
25	}
26
27	/**
28	* Checks the contents of the file for elements that make
29	* it a podcast feed.
30	*
31	* @param SimplePie\File $file The file being checked.
32	*/
33	private function is_podcast_feed( $file ) {
34	// If we can't read the DOM assume it's a podcast feed, we'll work
35	// it out later.
36	if ( ! class_exists( 'DOMDocument' ) ) {
37	return true;
38	}
39
40	$feed_dom = $this->safely_load_xml( (string) $file->body );
41
42	// Do this as either/or but prioritise the itunes namespace. It's pretty likely
43	// that it's a podcast feed we've found if that namespace is present.
44	return $feed_dom && $this->has_itunes_ns( $feed_dom ) && $this->has_audio_enclosures( $feed_dom );
45	}
46
47	/**
48	* Safely loads an XML file
49	*
50	* @param string $xml A string of XML to load.
51	* @return DOMDocument\|false A resulting DOM document or `false` if there is an error.
52	*/
53	private function safely_load_xml( $xml ) {
54	if ( empty( $xml ) ) {
55	return false;
56	}
57
58	$disable_entity_loader = PHP_VERSION_ID < 80000;
59
60	if ( $disable_entity_loader ) {
61	// This function has been deprecated in PHP 8.0 because in libxml 2.9.0, external entity loading
62	// is disabled by default, so this function is no longer needed to protect against XXE attacks.
63	// phpcs:ignore Generic.PHP.DeprecatedFunctions.Deprecated, PHPCompatibility.FunctionUse.RemovedFunctions.libxml_disable_entity_loaderDeprecated
64	$loader = libxml_disable_entity_loader( true );
65	}
66
67	$errors = libxml_use_internal_errors( true );
68
69	$return = new DOMDocument();
70	if ( ! $return->loadXML( $xml ) ) {
71	return false;
72	}
73
74	libxml_use_internal_errors( $errors );
75
76	if ( $disable_entity_loader && isset( $loader ) ) {
77	// phpcs:ignore Generic.PHP.DeprecatedFunctions.Deprecated, PHPCompatibility.FunctionUse.RemovedFunctions.libxml_disable_entity_loaderDeprecated
78	libxml_disable_entity_loader( $loader );
79	}
80
81	return $return;
82	}
83
84	/**
85	* Checks the RSS feed for the presence of the itunes podcast namespace.
86	* It's pretty loose and just checks the URI for itunes.com
87	*
88	* @param DOMDocument $dom The XML document to check.
89	* @return boolean Whether the itunes namespace is defined.
90	*/
91	private function has_itunes_ns( $dom ) {
92	$xpath = new DOMXPath( $dom );
93	foreach ( $xpath->query( 'namespace::*' ) as $node ) {
94	// phpcs:disable WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
95	// nodeValue is not valid, but it's part of the DOM API that we don't control.
96	if ( strstr( $node->nodeValue, 'itunes.com' ) ) {
97	return true;
98	}
99	// phpcs:enable
100	}
101	return false;
102	}
103
104	/**
105	* Checks the RSS feed for the presence of enclosures with an audio mimetype.
106	*
107	* @param DOMDocument $dom The XML document to check.
108	* @return boolean Whether enclosures were found.
109	*/
110	private function has_audio_enclosures( $dom ) {
111	$xpath = new DOMXPath( $dom );
112	$enclosures = $xpath->query( "//enclosure[starts-with(@type,'audio/')]" );
113	return ! $enclosures ? false : $enclosures->length > 0;
114	}
115	}
116