jetpack / modules / shortcodes / class.filter-embedded-html-objects.php

class.filter-embedded-html-objects.php in Jetpack – WP Security, Backup, Speed, & Growth 8.2, at modules/shortcodes/class.filter-embedded-html-objects.php

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1	<?php // phpcs:ignore WordPress.Files.FileName.InvalidClassFileName
2	/**
3	* The companion file to shortcodes.php
4	*
5	* This file contains the code that converts HTML embeds into shortcodes
6	* for when the user copy/pastes in HTML.
7	*
8	* @package Jetpack
9	*/
10
11	add_filter( 'pre_kses', array( 'Filter_Embedded_HTML_Objects', 'filter' ), 11 );
12	add_filter( 'pre_kses', array( 'Filter_Embedded_HTML_Objects', 'maybe_create_links' ), 100 ); // See WPCom_Embed_Stats::init().
13
14	/**
15	* Helper class for identifying and parsing known HTML embeds (iframe, object, embed, etc. elements), then converting them to shortcodes.
16	* For unknown HTML embeds, the class still tries to convert them to plain links so that at least something is preserved instead of having the entire element stripped by KSES.
17	*
18	* @since 4.5.0
19	*/
20	class Filter_Embedded_HTML_Objects {
21	/**
22	* Array of patterns to search for via strpos().
23	* Keys are patterns, values are callback functions that implement the HTML -> shortcode replacement.
24	* Patterns are matched against URLs (src or movie HTML attributes).
25	*
26	* @var array
27	*/
28	public static $strpos_filters = array();
29	/**
30	* Array of patterns to search for via preg_match().
31	* Keys are patterns, values are callback functions that implement the HTML -> shortcode replacement.
32	* Patterns are matched against URLs (src or movie HTML attributes).
33	*
34	* @var array
35	*/
36	public static $regexp_filters = array();
37	/**
38	* HTML element being processed.
39	*
40	* @var string
41	*/
42	public static $current_element = false;
43	/**
44	* Array of patterns to search for via strpos().
45	* Keys are patterns, values are callback functions that implement the HTML -> shortcode replacement.
46	* Patterns are matched against full HTML elements.
47	*
48	* @var array
49	*/
50	public static $html_strpos_filters = array();
51	/**
52	* Array of patterns to search for via preg_match().
53	* Keys are patterns, values are callback functions that implement the HTML -> shortcode replacement.
54	* Patterns are matched against full HTML elements.
55	*
56	* @var array
57	*/
58	public static $html_regexp_filters = array();
59	/**
60	* Failed embeds (stripped)
61	*
62	* @var array
63	*/
64	public static $failed_embeds = array();
65
66	/**
67	* Store tokens found in Syntax Highlighter.
68	*
69	* @since 4.5.0
70	*
71	* @var array
72	*/
73	private static $sh_unfiltered_content_tokens;
74
75	/**
76	* Capture tokens found in Syntax Highlighter and collect them in self::$sh_unfiltered_content_tokens.
77	*
78	* @since 4.5.0
79	*
80	* @param array $match Array of Syntax Highlighter matches.
81	*
82	* @return string
83	*/
84	public static function sh_regexp_callback( $match ) {
85	$token = sprintf(
86	'[prekses-filter-token-%1$d-%2$s-%1$d]',
87	wp_rand(),
88	md5( $match[0] )
89	);
90	self::$sh_unfiltered_content_tokens[ $token ] = $match[0];
91	return $token;
92	}
93
94	/**
95	* Look for HTML elements that match the registered patterns.
96	* Replace them with the HTML generated by the registered replacement callbacks.
97	*
98	* @param string $html Post content.
99	*/
100	public static function filter( $html ) {
101	if ( ! $html \|\| ! is_string( $html ) ) {
102	return $html;
103	}
104
105	$regexps = array(
106	'object' => '%<object[^>]+>(?>[^<]+(?><(?!/object>)[^<]+))</object>%i',
107	'embed' => '%<embed[^>]+>(?:\s</embed>)?%i',
108	'iframe' => '%<iframe[^>]+>(?>[^<]+(?><(?!/iframe>)[^<]+))</iframe>%i',
109	'div' => '%<div[^>]+>(?>[^<]+(?><(?!/div>)[^<]+)+)(?:</div>)+%i',
110	'script' => '%<script[^>]+>(?>[^<]+(?><(?!/script>)[^<]+))</script>%i',
111	);
112
113	$unfiltered_content_tokens = array();
114	self::$sh_unfiltered_content_tokens = array();
115
116	// Check here to make sure that SyntaxHighlighter is still used. (Just a little future proofing).
117	if ( class_exists( 'SyntaxHighlighter' ) ) {
118	/*
119	* Replace any "code" shortcode blocks with a token that we'll later replace with its original text.
120	* This will keep the contents of the shortcode from being filtered.
121	*/
122	global $SyntaxHighlighter; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.VariableNotSnakeCase
123
124	// Check to see if the $syntax_highlighter object has been created and is ready for use.
125	if ( isset( $SyntaxHighlighter ) && is_array( $SyntaxHighlighter->shortcodes ) ) { // phpcs:ignore WordPress.NamingConventions.ValidVariableName.VariableNotSnakeCase
126	$shortcode_regex = implode( '\|', array_map( 'preg_quote', $SyntaxHighlighter->shortcodes ) ); // phpcs:ignore WordPress.NamingConventions.ValidVariableName.VariableNotSnakeCase
127	$html = preg_replace_callback(
128	'/\[(' . $shortcode_regex . ')(\s[^\]])?\][\s\S]?\[\/\1\]/m',
129	array( __CLASS__, 'sh_regexp_callback' ),
130	$html
131	);
132	$unfiltered_content_tokens = self::$sh_unfiltered_content_tokens;
133	}
134	}
135
136	foreach ( $regexps as $element => $regexp ) {
137	self::$current_element = $element;
138
139	if ( false !== stripos( $html, "<$element" ) ) {
140	$new_html = preg_replace_callback( $regexp, array( __CLASS__, 'dispatch' ), $html );
141	if ( $new_html ) {
142	$html = $new_html;
143	}
144	}
145
146	if ( false !== stripos( $html, "<$element" ) ) {
147	$regexp_entities = self::regexp_entities( $regexp );
148	$new_html = preg_replace_callback( $regexp_entities, array( __CLASS__, 'dispatch_entities' ), $html );
149	if ( $new_html ) {
150	$html = $new_html;
151	}
152	}
153	}
154
155	if ( count( $unfiltered_content_tokens ) > 0 ) {
156	// Replace any tokens generated earlier with their original unfiltered text.
157	$html = str_replace( array_keys( $unfiltered_content_tokens ), $unfiltered_content_tokens, $html );
158	}
159
160	return $html;
161	}
162
163	/**
164	* Replace HTML entities in current HTML element regexp.
165	* This is useful when the content is HTML encoded by TinyMCE.
166	*
167	* @param string $regexp Selected regexp.
168	*/
169	public static function regexp_entities( $regexp ) {
170	return preg_replace(
171	'/\[\^&([^\]]+)\]\*\+/',
172	'(?>[^&]+(?>&(?!\1)[^&])+)*+',
173	str_replace( '?>', '?' . '>', htmlspecialchars( $regexp, ENT_NOQUOTES ) )
174	);
175	}
176
177	/**
178	* Register a filter to convert a matching HTML element to a shortcode.
179	*
180	* We can match the provided pattern against the source URL of the HTML element
181	* (generally the value of the src attribute of the HTML element), or against the full HTML element.
182	*
183	* The callback is passed an array containing the raw HTML of the element as well as pre-parsed attribute name/values.
184	*
185	* @param string $match Pattern to search for: either a regular expression to use with preg_match() or a search string to use with strpos().
186	* @param string $callback Function used to convert embed into shortcode.
187	* @param bool $is_regexp Is $match a regular expression? If true, match using preg_match(). If not, match using strpos(). Default false.
188	* @param bool $is_html_filter Match the pattern against the full HTML (true) or just the source URL (false)? Default false.
189	*/
190	public static function register( $match, $callback, $is_regexp = false, $is_html_filter = false ) {
191	if ( $is_html_filter ) {
192	if ( $is_regexp ) {
193	self::$html_regexp_filters[ $match ] = $callback;
194	} else {
195	self::$html_strpos_filters[ $match ] = $callback;
196	}
197	} else {
198	if ( $is_regexp ) {
199	self::$regexp_filters[ $match ] = $callback;
200	} else {
201	self::$strpos_filters[ $match ] = $callback;
202	}
203	}
204	}
205
206	/**
207	* Delete an existing registered pattern/replacement filter.
208	*
209	* @param string $match Embed regexp.
210	*/
211	public static function unregister( $match ) {
212	// Allow themes/plugins to remove registered embeds.
213	unset( self::$regexp_filters[ $match ] );
214	unset( self::$strpos_filters[ $match ] );
215	unset( self::$html_regexp_filters[ $match ] );
216	unset( self::$html_strpos_filters[ $match ] );
217	}
218
219	/**
220	* Filter and replace HTML element entity.
221	*
222	* @param array $matches Array of matches.
223	*/
224	private static function dispatch_entities( $matches ) {
225	$orig_html = $matches[0];
226	$decoded_matches = array( html_entity_decode( $matches[0] ) );
227
228	return self::dispatch( $decoded_matches, $orig_html );
229	}
230
231	/**
232	* Filter and replace HTML element.
233	*
234	* @param array $matches Array of matches.
235	* @param string $orig_html Original html. Returned if no results are found via $matches processing.
236	*/
237	private static function dispatch( $matches, $orig_html = null ) {
238	if ( null === $orig_html ) {
239	$orig_html = $matches[0];
240	}
241	$html = preg_replace( '%&#0*58;//%', '://', $matches[0] );
242	$attrs = self::get_attrs( $html );
243	if ( isset( $attrs['src'] ) ) {
244	$src = $attrs['src'];
245	} elseif ( isset( $attrs['movie'] ) ) {
246	$src = $attrs['movie'];
247	} else {
248	// no src found, search html.
249	foreach ( self::$html_strpos_filters as $match => $callback ) {
250	if ( false !== strpos( $html, $match ) ) {
251	return call_user_func( $callback, $attrs );
252	}
253	}
254
255	foreach ( self::$html_regexp_filters as $match => $callback ) {
256	if ( preg_match( $match, $html ) ) {
257	return call_user_func( $callback, $attrs );
258	}
259	}
260
261	return $orig_html;
262	}
263
264	$src = trim( $src );
265
266	// check source filter.
267	foreach ( self::$strpos_filters as $match => $callback ) {
268	if ( false !== strpos( $src, $match ) ) {
269	return call_user_func( $callback, $attrs );
270	}
271	}
272
273	foreach ( self::$regexp_filters as $match => $callback ) {
274	if ( preg_match( $match, $src ) ) {
275	return call_user_func( $callback, $attrs );
276	}
277	}
278
279	// check html filters.
280	foreach ( self::$html_strpos_filters as $match => $callback ) {
281	if ( false !== strpos( $html, $match ) ) {
282	return call_user_func( $callback, $attrs );
283	}
284	}
285
286	foreach ( self::$html_regexp_filters as $match => $callback ) {
287	if ( preg_match( $match, $html ) ) {
288	return call_user_func( $callback, $attrs );
289	}
290	}
291
292	// Log the strip.
293	if ( function_exists( 'wp_kses_reject' ) ) {
294	wp_kses_reject(
295	sprintf(
296	/* translators: placeholder is an HTML tag. */
297	__( '<code>%s</code> HTML tag removed as it is not allowed', 'jetpack' ),
298	'<' . self::$current_element . '>'
299	),
300	array( self::$current_element => $attrs )
301	);
302	}
303
304	// Keep the failed match so we can later replace it with a link,
305	// but return the original content to give others a chance too.
306	self::$failed_embeds[] = array(
307	'match' => $orig_html,
308	'src' => esc_url( $src ),
309	);
310
311	return $orig_html;
312	}
313
314	/**
315	* Failed embeds are stripped, so let's convert them to links at least.
316	*
317	* @param string $string Failed embed string.
318	*
319	* @return string $string Linkified string.
320	*/
321	public static function maybe_create_links( $string ) {
322	if ( empty( self::$failed_embeds ) ) {
323	return $string;
324	}
325
326	foreach ( self::$failed_embeds as $entry ) {
327	$html = sprintf( '<a href="%s">%s</a>', esc_url( $entry['src'] ), esc_url( $entry['src'] ) );
328	// Check if the string doesn't contain iframe, before replace.
329	if ( ! preg_match( '/<iframe /', $string ) ) {
330	$string = str_replace( $entry['match'], $html, $string );
331	}
332	}
333
334	self::$failed_embeds = array();
335
336	return $string;
337	}
338
339	/**
340	* Parse post HTML for HTML tags.
341	*
342	* @param string $html Post HTML.
343	*/
344	public static function get_attrs( $html ) {
345	if (
346	! ( class_exists( 'DOMDocument' ) && function_exists( 'libxml_use_internal_errors' ) && function_exists( 'simplexml_load_string' ) ) ) {
347	trigger_error( // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
348	esc_html__( 'PHP’s XML extension is not available. Please contact your hosting provider to enable PHP’s XML extension.', 'jetpack' )
349	);
350	return array();
351	}
352	// We have to go through DOM, since it can load non-well-formed XML (i.e. HTML). SimpleXML cannot.
353	$dom = new DOMDocument();
354	// The @ is not enough to suppress errors when dealing with libxml,
355	// we have to tell it directly how we want to handle errors.
356	libxml_use_internal_errors( true );
357	// Suppress parser warnings.
358	@$dom->loadHTML( $html ); // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
359	libxml_use_internal_errors( false );
360	$xml = false;
361	// phpcs:disable WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
362	foreach ( $dom->childNodes as $node ) {
363	// find the root node (html).
364	if ( XML_ELEMENT_NODE === $node->nodeType ) {
365	/*
366	* Use simplexml_load_string rather than simplexml_import_dom
367	* as the later doesn't cope well if the XML is malformmed in the DOM
368	* See #1688-wpcom.
369	*/
370	libxml_use_internal_errors( true );
371	// html->body->object.
372	$xml = simplexml_load_string( $dom->saveXML( $node->firstChild->firstChild ) );
373	libxml_clear_errors();
374	break;
375	}
376	}
377	// phpcs:enable WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
378
379	if ( ! $xml ) {
380	return array();
381	}
382
383	$attrs = array();
384	$attrs['_raw_html'] = $html;
385
386	// <param> elements
387	foreach ( $xml->param as $param ) {
388	$attrs[ (string) $param['name'] ] = (string) $param['value'];
389	}
390
391	// <object> attributes
392	foreach ( $xml->attributes() as $name => $attr ) {
393	$attrs[ $name ] = (string) $attr;
394	}
395
396	// <embed> attributes
397	if ( $xml->embed ) {
398	foreach ( $xml->embed->attributes() as $name => $attr ) {
399	$attrs[ $name ] = (string) $attr;
400	}
401	}
402
403	return $attrs;
404	}
405	}
406