class-jetpack-podcast-feed-locator.php — Jetpack – WP Security, Backup, Speed, & Growth 16.1-a.5

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

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class-jetpack-podcast-feed-locator.php

125 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	/**
18	* Overrides the locator is_feed function to check for
19	* appropriate podcast elements.
20	*
21	* @param SimplePie\HTTP\Response $file The file being checked.
22	* @param boolean $check_html Adds text/html to the mimetypes checked.
23	*/
24	public function is_feed( $file, $check_html = false ) {
25	return parent::is_feed( $file, $check_html ) &&
26	$file instanceof SimplePie\File &&
27	$this->is_podcast_feed( $file );
28	}
29
30	/**
31	* Checks the contents of the file for elements that make
32	* it a podcast feed.
33	*
34	* @param SimplePie\File $file The file being checked.
35	*/
36	private function is_podcast_feed( $file ) {
37	// If we can't read the DOM assume it's a podcast feed, we'll work
38	// it out later.
39	if ( ! class_exists( 'DOMDocument' ) ) {
40	return true;
41	}
42
43	// @todo Drop is_callable check once Simple gets the SimplePie update that came with WordPress 6.9.
44	if ( is_callable( array( $file, 'get_body_content' ) ) ) {
45	$feed_dom = $this->safely_load_xml( $file->get_body_content() );
46	} else {
47	// @phan-suppress-next-line PhanDeprecatedProperty -- For compatibility only.
48	$feed_dom = $this->safely_load_xml( (string) $file->body );
49	}
50
51	// Do this as either/or but prioritise the itunes namespace. It's pretty likely
52	// that it's a podcast feed we've found if that namespace is present.
53	return $feed_dom && $this->has_itunes_ns( $feed_dom ) && $this->has_audio_enclosures( $feed_dom );
54	}
55
56	/**
57	* Safely loads an XML file
58	*
59	* @param string $xml A string of XML to load.
60	* @return DOMDocument\|false A resulting DOM document or `false` if there is an error.
61	*/
62	private function safely_load_xml( $xml ) {
63	if ( empty( $xml ) ) {
64	return false;
65	}
66
67	$disable_entity_loader = PHP_VERSION_ID < 80000;
68
69	if ( $disable_entity_loader ) {
70	// This function has been deprecated in PHP 8.0 because in libxml 2.9.0, external entity loading
71	// is disabled by default, so this function is no longer needed to protect against XXE attacks.
72	// phpcs:ignore Generic.PHP.DeprecatedFunctions.Deprecated, PHPCompatibility.FunctionUse.RemovedFunctions.libxml_disable_entity_loaderDeprecated
73	$loader = libxml_disable_entity_loader( true );
74	}
75
76	$errors = libxml_use_internal_errors( true );
77
78	$return = new DOMDocument();
79	if ( ! $return->loadXML( $xml ) ) {
80	return false;
81	}
82
83	libxml_use_internal_errors( $errors );
84
85	if ( $disable_entity_loader && isset( $loader ) ) {
86	// phpcs:ignore Generic.PHP.DeprecatedFunctions.Deprecated, PHPCompatibility.FunctionUse.RemovedFunctions.libxml_disable_entity_loaderDeprecated
87	libxml_disable_entity_loader( $loader );
88	}
89
90	return $return;
91	}
92
93	/**
94	* Checks the RSS feed for the presence of the itunes podcast namespace.
95	* It's pretty loose and just checks the URI for itunes.com
96	*
97	* @param DOMDocument $dom The XML document to check.
98	* @return boolean Whether the itunes namespace is defined.
99	*/
100	private function has_itunes_ns( $dom ) {
101	$xpath = new DOMXPath( $dom );
102	foreach ( $xpath->query( 'namespace::*' ) as $node ) {
103	// phpcs:disable WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
104	// nodeValue is not valid, but it's part of the DOM API that we don't control.
105	if ( strstr( $node->nodeValue, 'itunes.com' ) ) {
106	return true;
107	}
108	// phpcs:enable
109	}
110	return false;
111	}
112
113	/**
114	* Checks the RSS feed for the presence of enclosures with an audio mimetype.
115	*
116	* @param DOMDocument $dom The XML document to check.
117	* @return boolean Whether enclosures were found.
118	*/
119	private function has_audio_enclosures( $dom ) {
120	$xpath = new DOMXPath( $dom );
121	$enclosures = $xpath->query( "//enclosure[starts-with(@type,'audio/')]" );
122	return ! $enclosures ? false : $enclosures->length > 0;
123	}
124	}
125