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annotate core/lib/Drupal/Component/Utility/Html.php @ 19:fa3358dc1485 tip

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Add ndrum files
author Chris Cannam
date Wed, 28 Aug 2019 13:14:47 +0100
parents 129ea1e6d783
children
rev   line source
Chris@0 1 <?php
Chris@0 2
Chris@0 3 namespace Drupal\Component\Utility;
Chris@0 4
Chris@0 5 /**
Chris@0 6 * Provides DOMDocument helpers for parsing and serializing HTML strings.
Chris@0 7 *
Chris@0 8 * @ingroup utility
Chris@0 9 */
Chris@0 10 class Html {
Chris@0 11
Chris@0 12 /**
Chris@0 13 * An array of previously cleaned HTML classes.
Chris@0 14 *
Chris@0 15 * @var array
Chris@0 16 */
Chris@0 17 protected static $classes = [];
Chris@0 18
Chris@0 19 /**
Chris@0 20 * An array of the initial IDs used in one request.
Chris@0 21 *
Chris@0 22 * @var array
Chris@0 23 */
Chris@0 24 protected static $seenIdsInit;
Chris@0 25
Chris@0 26 /**
Chris@0 27 * An array of IDs, including incremented versions when an ID is duplicated.
Chris@0 28 * @var array
Chris@0 29 */
Chris@0 30 protected static $seenIds;
Chris@0 31
Chris@0 32 /**
Chris@0 33 * Stores whether the current request was sent via AJAX.
Chris@0 34 *
Chris@0 35 * @var bool
Chris@0 36 */
Chris@0 37 protected static $isAjax = FALSE;
Chris@0 38
Chris@0 39 /**
Chris@0 40 * All attributes that may contain URIs.
Chris@0 41 *
Chris@0 42 * - The attributes 'code' and 'codebase' are omitted, because they only exist
Chris@0 43 * for the <applet> tag. The time of Java applets has passed.
Chris@0 44 * - The attribute 'icon' is omitted, because no browser implements the
Chris@0 45 * <command> tag anymore.
Chris@0 46 * See https://developer.mozilla.org/en-US/docs/Web/HTML/Element/command.
Chris@0 47 * - The 'manifest' attribute is omitted because it only exists for the <html>
Chris@0 48 * tag. That tag only makes sense in a HTML-served-as-HTML context, in which
Chris@0 49 * case relative URLs are guaranteed to work.
Chris@0 50 *
Chris@0 51 * @see https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes
Chris@0 52 * @see https://stackoverflow.com/questions/2725156/complete-list-of-html-tag-attributes-which-have-a-url-value
Chris@0 53 *
Chris@0 54 * @var string[]
Chris@0 55 */
Chris@0 56 protected static $uriAttributes = ['href', 'poster', 'src', 'cite', 'data', 'action', 'formaction', 'srcset', 'about'];
Chris@0 57
Chris@0 58 /**
Chris@0 59 * Prepares a string for use as a valid class name.
Chris@0 60 *
Chris@0 61 * Do not pass one string containing multiple classes as they will be
Chris@0 62 * incorrectly concatenated with dashes, i.e. "one two" will become "one-two".
Chris@0 63 *
Chris@0 64 * @param mixed $class
Chris@0 65 * The class name to clean. It can be a string or anything that can be cast
Chris@0 66 * to string.
Chris@0 67 *
Chris@0 68 * @return string
Chris@0 69 * The cleaned class name.
Chris@0 70 */
Chris@0 71 public static function getClass($class) {
Chris@0 72 $class = (string) $class;
Chris@0 73 if (!isset(static::$classes[$class])) {
Chris@17 74 static::$classes[$class] = static::cleanCssIdentifier(mb_strtolower($class));
Chris@0 75 }
Chris@0 76 return static::$classes[$class];
Chris@0 77 }
Chris@0 78
Chris@0 79 /**
Chris@0 80 * Prepares a string for use as a CSS identifier (element, class, or ID name).
Chris@0 81 *
Chris@17 82 * Link below shows the syntax for valid CSS identifiers (including element
Chris@17 83 * names, classes, and IDs in selectors).
Chris@17 84 *
Chris@17 85 * @see http://www.w3.org/TR/CSS21/syndata.html#characters
Chris@0 86 *
Chris@0 87 * @param string $identifier
Chris@0 88 * The identifier to clean.
Chris@0 89 * @param array $filter
Chris@0 90 * An array of string replacements to use on the identifier.
Chris@0 91 *
Chris@0 92 * @return string
Chris@0 93 * The cleaned identifier.
Chris@0 94 */
Chris@0 95 public static function cleanCssIdentifier($identifier, array $filter = [
Chris@0 96 ' ' => '-',
Chris@0 97 '_' => '-',
Chris@0 98 '/' => '-',
Chris@0 99 '[' => '-',
Chris@0 100 ']' => '',
Chris@0 101 ]) {
Chris@0 102 // We could also use strtr() here but its much slower than str_replace(). In
Chris@0 103 // order to keep '__' to stay '__' we first replace it with a different
Chris@0 104 // placeholder after checking that it is not defined as a filter.
Chris@0 105 $double_underscore_replacements = 0;
Chris@0 106 if (!isset($filter['__'])) {
Chris@0 107 $identifier = str_replace('__', '##', $identifier, $double_underscore_replacements);
Chris@0 108 }
Chris@0 109 $identifier = str_replace(array_keys($filter), array_values($filter), $identifier);
Chris@0 110 // Replace temporary placeholder '##' with '__' only if the original
Chris@0 111 // $identifier contained '__'.
Chris@0 112 if ($double_underscore_replacements > 0) {
Chris@0 113 $identifier = str_replace('##', '__', $identifier);
Chris@0 114 }
Chris@0 115
Chris@0 116 // Valid characters in a CSS identifier are:
Chris@0 117 // - the hyphen (U+002D)
Chris@0 118 // - a-z (U+0030 - U+0039)
Chris@0 119 // - A-Z (U+0041 - U+005A)
Chris@0 120 // - the underscore (U+005F)
Chris@0 121 // - 0-9 (U+0061 - U+007A)
Chris@0 122 // - ISO 10646 characters U+00A1 and higher
Chris@0 123 // We strip out any character not in the above list.
Chris@0 124 $identifier = preg_replace('/[^\x{002D}\x{0030}-\x{0039}\x{0041}-\x{005A}\x{005F}\x{0061}-\x{007A}\x{00A1}-\x{FFFF}]/u', '', $identifier);
Chris@0 125 // Identifiers cannot start with a digit, two hyphens, or a hyphen followed by a digit.
Chris@0 126 $identifier = preg_replace([
Chris@0 127 '/^[0-9]/',
Chris@17 128 '/^(-[0-9])|^(--)/',
Chris@0 129 ], ['_', '__'], $identifier);
Chris@0 130 return $identifier;
Chris@0 131 }
Chris@0 132
Chris@0 133 /**
Chris@0 134 * Sets if this request is an Ajax request.
Chris@0 135 *
Chris@0 136 * @param bool $is_ajax
Chris@0 137 * TRUE if this request is an Ajax request, FALSE otherwise.
Chris@0 138 */
Chris@0 139 public static function setIsAjax($is_ajax) {
Chris@0 140 static::$isAjax = $is_ajax;
Chris@0 141 }
Chris@0 142
Chris@0 143 /**
Chris@0 144 * Prepares a string for use as a valid HTML ID and guarantees uniqueness.
Chris@0 145 *
Chris@0 146 * This function ensures that each passed HTML ID value only exists once on
Chris@0 147 * the page. By tracking the already returned ids, this function enables
Chris@0 148 * forms, blocks, and other content to be output multiple times on the same
Chris@0 149 * page, without breaking (X)HTML validation.
Chris@0 150 *
Chris@0 151 * For already existing IDs, a counter is appended to the ID string.
Chris@0 152 * Therefore, JavaScript and CSS code should not rely on any value that was
Chris@0 153 * generated by this function and instead should rely on manually added CSS
Chris@0 154 * classes or similarly reliable constructs.
Chris@0 155 *
Chris@0 156 * Two consecutive hyphens separate the counter from the original ID. To
Chris@0 157 * manage uniqueness across multiple Ajax requests on the same page, Ajax
Chris@0 158 * requests POST an array of all IDs currently present on the page, which are
Chris@0 159 * used to prime this function's cache upon first invocation.
Chris@0 160 *
Chris@0 161 * To allow reverse-parsing of IDs submitted via Ajax, any multiple
Chris@0 162 * consecutive hyphens in the originally passed $id are replaced with a
Chris@0 163 * single hyphen.
Chris@0 164 *
Chris@0 165 * @param string $id
Chris@0 166 * The ID to clean.
Chris@0 167 *
Chris@0 168 * @return string
Chris@0 169 * The cleaned ID.
Chris@0 170 */
Chris@0 171 public static function getUniqueId($id) {
Chris@0 172 // If this is an Ajax request, then content returned by this page request
Chris@0 173 // will be merged with content already on the base page. The HTML IDs must
Chris@0 174 // be unique for the fully merged content. Therefore use unique IDs.
Chris@0 175 if (static::$isAjax) {
Chris@0 176 return static::getId($id) . '--' . Crypt::randomBytesBase64(8);
Chris@0 177 }
Chris@0 178
Chris@0 179 // @todo Remove all that code once we switch over to random IDs only,
Chris@0 180 // see https://www.drupal.org/node/1090592.
Chris@0 181 if (!isset(static::$seenIdsInit)) {
Chris@0 182 static::$seenIdsInit = [];
Chris@0 183 }
Chris@0 184 if (!isset(static::$seenIds)) {
Chris@0 185 static::$seenIds = static::$seenIdsInit;
Chris@0 186 }
Chris@0 187
Chris@0 188 $id = static::getId($id);
Chris@0 189
Chris@0 190 // Ensure IDs are unique by appending a counter after the first occurrence.
Chris@0 191 // The counter needs to be appended with a delimiter that does not exist in
Chris@0 192 // the base ID. Requiring a unique delimiter helps ensure that we really do
Chris@0 193 // return unique IDs and also helps us re-create the $seen_ids array during
Chris@0 194 // Ajax requests.
Chris@0 195 if (isset(static::$seenIds[$id])) {
Chris@0 196 $id = $id . '--' . ++static::$seenIds[$id];
Chris@0 197 }
Chris@0 198 else {
Chris@0 199 static::$seenIds[$id] = 1;
Chris@0 200 }
Chris@0 201 return $id;
Chris@0 202 }
Chris@0 203
Chris@0 204 /**
Chris@0 205 * Prepares a string for use as a valid HTML ID.
Chris@0 206 *
Chris@0 207 * Only use this function when you want to intentionally skip the uniqueness
Chris@0 208 * guarantee of self::getUniqueId().
Chris@0 209 *
Chris@0 210 * @param string $id
Chris@0 211 * The ID to clean.
Chris@0 212 *
Chris@0 213 * @return string
Chris@0 214 * The cleaned ID.
Chris@0 215 *
Chris@0 216 * @see self::getUniqueId()
Chris@0 217 */
Chris@0 218 public static function getId($id) {
Chris@17 219 $id = str_replace([' ', '_', '[', ']'], ['-', '-', '-', ''], mb_strtolower($id));
Chris@0 220
Chris@0 221 // As defined in http://www.w3.org/TR/html4/types.html#type-name, HTML IDs can
Chris@0 222 // only contain letters, digits ([0-9]), hyphens ("-"), underscores ("_"),
Chris@0 223 // colons (":"), and periods ("."). We strip out any character not in that
Chris@0 224 // list. Note that the CSS spec doesn't allow colons or periods in identifiers
Chris@0 225 // (http://www.w3.org/TR/CSS21/syndata.html#characters), so we strip those two
Chris@0 226 // characters as well.
Chris@0 227 $id = preg_replace('/[^A-Za-z0-9\-_]/', '', $id);
Chris@0 228
Chris@0 229 // Removing multiple consecutive hyphens.
Chris@0 230 $id = preg_replace('/\-+/', '-', $id);
Chris@0 231 return $id;
Chris@0 232 }
Chris@0 233
Chris@0 234 /**
Chris@0 235 * Resets the list of seen IDs.
Chris@0 236 */
Chris@0 237 public static function resetSeenIds() {
Chris@0 238 static::$seenIds = NULL;
Chris@0 239 }
Chris@0 240
Chris@0 241 /**
Chris@0 242 * Normalizes an HTML snippet.
Chris@0 243 *
Chris@0 244 * This function is essentially \DOMDocument::normalizeDocument(), but
Chris@0 245 * operates on an HTML string instead of a \DOMDocument.
Chris@0 246 *
Chris@0 247 * @param string $html
Chris@0 248 * The HTML string to normalize.
Chris@0 249 *
Chris@0 250 * @return string
Chris@0 251 * The normalized HTML string.
Chris@0 252 */
Chris@0 253 public static function normalize($html) {
Chris@0 254 $document = static::load($html);
Chris@0 255 return static::serialize($document);
Chris@0 256 }
Chris@0 257
Chris@0 258 /**
Chris@0 259 * Parses an HTML snippet and returns it as a DOM object.
Chris@0 260 *
Chris@0 261 * This function loads the body part of a partial (X)HTML document and returns
Chris@0 262 * a full \DOMDocument object that represents this document.
Chris@0 263 *
Chris@0 264 * Use \Drupal\Component\Utility\Html::serialize() to serialize this
Chris@0 265 * \DOMDocument back to a string.
Chris@0 266 *
Chris@0 267 * @param string $html
Chris@0 268 * The partial (X)HTML snippet to load. Invalid markup will be corrected on
Chris@0 269 * import.
Chris@0 270 *
Chris@0 271 * @return \DOMDocument
Chris@0 272 * A \DOMDocument that represents the loaded (X)HTML snippet.
Chris@0 273 */
Chris@0 274 public static function load($html) {
Chris@0 275 $document = <<<EOD
Chris@0 276 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
Chris@0 277 <html xmlns="http://www.w3.org/1999/xhtml">
Chris@0 278 <head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head>
Chris@0 279 <body>!html</body>
Chris@0 280 </html>
Chris@0 281 EOD;
Chris@0 282 // PHP's \DOMDocument serialization adds extra whitespace when the markup
Chris@0 283 // of the wrapping document contains newlines, so ensure we remove all
Chris@0 284 // newlines before injecting the actual HTML body to be processed.
Chris@0 285 $document = strtr($document, ["\n" => '', '!html' => $html]);
Chris@0 286
Chris@0 287 $dom = new \DOMDocument();
Chris@0 288 // Ignore warnings during HTML soup loading.
Chris@0 289 @$dom->loadHTML($document);
Chris@0 290
Chris@0 291 return $dom;
Chris@0 292 }
Chris@0 293
Chris@0 294 /**
Chris@0 295 * Converts the body of a \DOMDocument back to an HTML snippet.
Chris@0 296 *
Chris@0 297 * The function serializes the body part of a \DOMDocument back to an (X)HTML
Chris@0 298 * snippet. The resulting (X)HTML snippet will be properly formatted to be
Chris@0 299 * compatible with HTML user agents.
Chris@0 300 *
Chris@0 301 * @param \DOMDocument $document
Chris@0 302 * A \DOMDocument object to serialize, only the tags below the first <body>
Chris@0 303 * node will be converted.
Chris@0 304 *
Chris@0 305 * @return string
Chris@0 306 * A valid (X)HTML snippet, as a string.
Chris@0 307 */
Chris@0 308 public static function serialize(\DOMDocument $document) {
Chris@0 309 $body_node = $document->getElementsByTagName('body')->item(0);
Chris@0 310 $html = '';
Chris@0 311
Chris@0 312 if ($body_node !== NULL) {
Chris@0 313 foreach ($body_node->getElementsByTagName('script') as $node) {
Chris@0 314 static::escapeCdataElement($node);
Chris@0 315 }
Chris@0 316 foreach ($body_node->getElementsByTagName('style') as $node) {
Chris@0 317 static::escapeCdataElement($node, '/*', '*/');
Chris@0 318 }
Chris@0 319 foreach ($body_node->childNodes as $node) {
Chris@0 320 $html .= $document->saveXML($node);
Chris@0 321 }
Chris@0 322 }
Chris@0 323 return $html;
Chris@0 324 }
Chris@0 325
Chris@0 326 /**
Chris@0 327 * Adds comments around a <!CDATA section in a \DOMNode.
Chris@0 328 *
Chris@0 329 * \DOMDocument::loadHTML() in \Drupal\Component\Utility\Html::load() makes
Chris@0 330 * CDATA sections from the contents of inline script and style tags. This can
Chris@0 331 * cause HTML4 browsers to throw exceptions.
Chris@0 332 *
Chris@0 333 * This function attempts to solve the problem by creating a
Chris@0 334 * \DOMDocumentFragment to comment the CDATA tag.
Chris@0 335 *
Chris@0 336 * @param \DOMNode $node
Chris@0 337 * The element potentially containing a CDATA node.
Chris@0 338 * @param string $comment_start
Chris@0 339 * (optional) A string to use as a comment start marker to escape the CDATA
Chris@0 340 * declaration. Defaults to '//'.
Chris@0 341 * @param string $comment_end
Chris@0 342 * (optional) A string to use as a comment end marker to escape the CDATA
Chris@0 343 * declaration. Defaults to an empty string.
Chris@0 344 */
Chris@0 345 public static function escapeCdataElement(\DOMNode $node, $comment_start = '//', $comment_end = '') {
Chris@0 346 foreach ($node->childNodes as $child_node) {
Chris@0 347 if ($child_node instanceof \DOMCdataSection) {
Chris@0 348 $embed_prefix = "\n<!--{$comment_start}--><![CDATA[{$comment_start} ><!--{$comment_end}\n";
Chris@0 349 $embed_suffix = "\n{$comment_start}--><!]]>{$comment_end}\n";
Chris@0 350
Chris@0 351 // Prevent invalid cdata escaping as this would throw a DOM error.
Chris@0 352 // This is the same behavior as found in libxml2.
Chris@0 353 // Related W3C standard: http://www.w3.org/TR/REC-xml/#dt-cdsection
Chris@0 354 // Fix explanation: http://wikipedia.org/wiki/CDATA#Nesting
Chris@0 355 $data = str_replace(']]>', ']]]]><![CDATA[>', $child_node->data);
Chris@0 356
Chris@0 357 $fragment = $node->ownerDocument->createDocumentFragment();
Chris@0 358 $fragment->appendXML($embed_prefix . $data . $embed_suffix);
Chris@0 359 $node->appendChild($fragment);
Chris@0 360 $node->removeChild($child_node);
Chris@0 361 }
Chris@0 362 }
Chris@0 363 }
Chris@0 364
Chris@0 365 /**
Chris@0 366 * Decodes all HTML entities including numerical ones to regular UTF-8 bytes.
Chris@0 367 *
Chris@0 368 * Double-escaped entities will only be decoded once ("&amp;lt;" becomes
Chris@0 369 * "&lt;", not "<"). Be careful when using this function, as it will revert
Chris@0 370 * previous sanitization efforts (&lt;script&gt; will become <script>).
Chris@0 371 *
Chris@0 372 * This method is not the opposite of Html::escape(). For example, this method
Chris@0 373 * will convert "&eacute;" to "é", whereas Html::escape() will not convert "é"
Chris@0 374 * to "&eacute;".
Chris@0 375 *
Chris@0 376 * @param string $text
Chris@0 377 * The text to decode entities in.
Chris@0 378 *
Chris@0 379 * @return string
Chris@0 380 * The input $text, with all HTML entities decoded once.
Chris@0 381 *
Chris@0 382 * @see html_entity_decode()
Chris@0 383 * @see \Drupal\Component\Utility\Html::escape()
Chris@0 384 */
Chris@0 385 public static function decodeEntities($text) {
Chris@0 386 return html_entity_decode($text, ENT_QUOTES, 'UTF-8');
Chris@0 387 }
Chris@0 388
Chris@0 389 /**
Chris@0 390 * Escapes text by converting special characters to HTML entities.
Chris@0 391 *
Chris@0 392 * This method escapes HTML for sanitization purposes by replacing the
Chris@0 393 * following special characters with their HTML entity equivalents:
Chris@0 394 * - & (ampersand) becomes &amp;
Chris@0 395 * - " (double quote) becomes &quot;
Chris@0 396 * - ' (single quote) becomes &#039;
Chris@0 397 * - < (less than) becomes &lt;
Chris@0 398 * - > (greater than) becomes &gt;
Chris@0 399 * Special characters that have already been escaped will be double-escaped
Chris@0 400 * (for example, "&lt;" becomes "&amp;lt;"), and invalid UTF-8 encoding
Chris@0 401 * will be converted to the Unicode replacement character ("�").
Chris@0 402 *
Chris@0 403 * This method is not the opposite of Html::decodeEntities(). For example,
Chris@0 404 * this method will not encode "é" to "&eacute;", whereas
Chris@0 405 * Html::decodeEntities() will convert all HTML entities to UTF-8 bytes,
Chris@0 406 * including "&eacute;" and "&lt;" to "é" and "<".
Chris@0 407 *
Chris@0 408 * When constructing @link theme_render render arrays @endlink passing the output of Html::escape() to
Chris@0 409 * '#markup' is not recommended. Use the '#plain_text' key instead and the
Chris@0 410 * renderer will autoescape the text.
Chris@0 411 *
Chris@0 412 * @param string $text
Chris@0 413 * The input text.
Chris@0 414 *
Chris@0 415 * @return string
Chris@0 416 * The text with all HTML special characters converted.
Chris@0 417 *
Chris@0 418 * @see htmlspecialchars()
Chris@0 419 * @see \Drupal\Component\Utility\Html::decodeEntities()
Chris@0 420 *
Chris@0 421 * @ingroup sanitization
Chris@0 422 */
Chris@0 423 public static function escape($text) {
Chris@0 424 return htmlspecialchars($text, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
Chris@0 425 }
Chris@0 426
Chris@0 427 /**
Chris@0 428 * Converts all root-relative URLs to absolute URLs.
Chris@0 429 *
Chris@0 430 * Does not change any existing protocol-relative or absolute URLs. Does not
Chris@0 431 * change other relative URLs because they would result in different absolute
Chris@0 432 * URLs depending on the current path. For example: when the same content
Chris@0 433 * containing such a relative URL (for example 'image.png'), is served from
Chris@0 434 * its canonical URL (for example 'http://example.com/some-article') or from
Chris@0 435 * a listing or feed (for example 'http://example.com/all-articles') their
Chris@0 436 * "current path" differs, resulting in different absolute URLs:
Chris@0 437 * 'http://example.com/some-article/image.png' versus
Chris@0 438 * 'http://example.com/all-articles/image.png'. Only one can be correct.
Chris@0 439 * Therefore relative URLs that are not root-relative cannot be safely
Chris@0 440 * transformed and should generally be avoided.
Chris@0 441 *
Chris@0 442 * Necessary for HTML that is served outside of a website, for example, RSS
Chris@0 443 * and e-mail.
Chris@0 444 *
Chris@0 445 * @param string $html
Chris@0 446 * The partial (X)HTML snippet to load. Invalid markup will be corrected on
Chris@0 447 * import.
Chris@0 448 * @param string $scheme_and_host
Chris@0 449 * The root URL, which has a URI scheme, host and optional port.
Chris@0 450 *
Chris@0 451 * @return string
Chris@0 452 * The updated (X)HTML snippet.
Chris@0 453 */
Chris@0 454 public static function transformRootRelativeUrlsToAbsolute($html, $scheme_and_host) {
Chris@14 455 assert(empty(array_diff(array_keys(parse_url($scheme_and_host)), ["scheme", "host", "port"])), '$scheme_and_host contains scheme, host and port at most.');
Chris@14 456 assert(isset(parse_url($scheme_and_host)["scheme"]), '$scheme_and_host is absolute and hence has a scheme.');
Chris@14 457 assert(isset(parse_url($scheme_and_host)["host"]), '$base_url is absolute and hence has a host.');
Chris@0 458
Chris@0 459 $html_dom = Html::load($html);
Chris@0 460 $xpath = new \DOMXpath($html_dom);
Chris@0 461
Chris@0 462 // Update all root-relative URLs to absolute URLs in the given HTML.
Chris@0 463 foreach (static::$uriAttributes as $attr) {
Chris@0 464 foreach ($xpath->query("//*[starts-with(@$attr, '/') and not(starts-with(@$attr, '//'))]") as $node) {
Chris@0 465 $node->setAttribute($attr, $scheme_and_host . $node->getAttribute($attr));
Chris@0 466 }
Chris@0 467 foreach ($xpath->query("//*[@srcset]") as $node) {
Chris@0 468 // @see https://html.spec.whatwg.org/multipage/embedded-content.html#attr-img-srcset
Chris@0 469 // @see https://html.spec.whatwg.org/multipage/embedded-content.html#image-candidate-string
Chris@0 470 $image_candidate_strings = explode(',', $node->getAttribute('srcset'));
Chris@0 471 $image_candidate_strings = array_map('trim', $image_candidate_strings);
Chris@0 472 for ($i = 0; $i < count($image_candidate_strings); $i++) {
Chris@0 473 $image_candidate_string = $image_candidate_strings[$i];
Chris@0 474 if ($image_candidate_string[0] === '/' && $image_candidate_string[1] !== '/') {
Chris@0 475 $image_candidate_strings[$i] = $scheme_and_host . $image_candidate_string;
Chris@0 476 }
Chris@0 477 }
Chris@0 478 $node->setAttribute('srcset', implode(', ', $image_candidate_strings));
Chris@0 479 }
Chris@0 480 }
Chris@0 481 return Html::serialize($html_dom);
Chris@0 482 }
Chris@0 483
Chris@0 484 }