includes/Html.php

   1 <?php
   2 /**
   3  * Collection of methods to generate HTML content
   4  *
   5  * Copyright © 2009 Aryeh Gregor
   6  * https://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  */
  25 use MediaWiki\MediaWikiServices;
  26
  27 /**
  28  * This class is a collection of static functions that serve two purposes:
  29  *
  30  * 1) Implement any algorithms specified by HTML5, or other HTML
  31  * specifications, in a convenient and self-contained way.
  32  *
  33  * 2) Allow HTML elements to be conveniently and safely generated, like the
  34  * current Xml class but a) less confused (Xml supports HTML-specific things,
  35  * but only sometimes!) and b) not necessarily confined to XML-compatible
  36  * output.
  37  *
  38  * There are two important configuration options this class uses:
  39  *
  40  * $wgMimeType: If this is set to an xml MIME type then output should be
  41  *     valid XHTML5.
  42  *
  43  * This class is meant to be confined to utility functions that are called from
  44  * trusted code paths.  It does not do enforcement of policy like not allowing
  45  * <a> elements.
  46  *
  47  * @since 1.16
  48  */
  49 class Html {
  50         // List of void elements from HTML5, section 8.1.2 as of 2016-09-19
  51         private static $voidElements = [
  52                 'area',
  53                 'base',
  54                 'br',
  55                 'col',
  56                 'embed',
  57                 'hr',
  58                 'img',
  59                 'input',
  60                 'keygen',
  61                 'link',
  62                 'meta',
  63                 'param',
  64                 'source',
  65                 'track',
  66                 'wbr',
  67         ];
  68
  69         // Boolean attributes, which may have the value omitted entirely.  Manually
  70         // collected from the HTML5 spec as of 2011-08-12.
  71         private static $boolAttribs = [
  72                 'async',
  73                 'autofocus',
  74                 'autoplay',
  75                 'checked',
  76                 'controls',
  77                 'default',
  78                 'defer',
  79                 'disabled',
  80                 'formnovalidate',
  81                 'hidden',
  82                 'ismap',
  83                 'itemscope',
  84                 'loop',
  85                 'multiple',
  86                 'muted',
  87                 'novalidate',
  88                 'open',
  89                 'pubdate',
  90                 'readonly',
  91                 'required',
  92                 'reversed',
  93                 'scoped',
  94                 'seamless',
  95                 'selected',
  96                 'truespeed',
  97                 'typemustmatch',
  98                 // HTML5 Microdata
  99                 'itemscope',
 100         ];
 101
 102         /**
 103          * Modifies a set of attributes meant for button elements
 104          * and apply a set of default attributes when $wgUseMediaWikiUIEverywhere enabled.
 105          * @param array $attrs HTML attributes in an associative array
 106          * @param string[] $modifiers classes to add to the button
 107          * @see https://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 108          * @return array $attrs A modified attribute array
 109          */
 110         public static function buttonAttributes( array $attrs, array $modifiers = [] ) {
 111                 global $wgUseMediaWikiUIEverywhere;
 112                 if ( $wgUseMediaWikiUIEverywhere ) {
 113                         if ( isset( $attrs['class'] ) ) {
 114                                 if ( is_array( $attrs['class'] ) ) {
 115                                         $attrs['class'][] = 'mw-ui-button';
 116                                         $attrs['class'] = array_merge( $attrs['class'], $modifiers );
 117                                         // ensure compatibility with Xml
 118                                         $attrs['class'] = implode( ' ', $attrs['class'] );
 119                                 } else {
 120                                         $attrs['class'] .= ' mw-ui-button ' . implode( ' ', $modifiers );
 121                                 }
 122                         } else {
 123                                 // ensure compatibility with Xml
 124                                 $attrs['class'] = 'mw-ui-button ' . implode( ' ', $modifiers );
 125                         }
 126                 }
 127                 return $attrs;
 128         }
 129
 130         /**
 131          * Modifies a set of attributes meant for text input elements
 132          * and apply a set of default attributes.
 133          * Removes size attribute when $wgUseMediaWikiUIEverywhere enabled.
 134          * @param array $attrs An attribute array.
 135          * @return array $attrs A modified attribute array
 136          */
 137         public static function getTextInputAttributes( array $attrs ) {
 138                 global $wgUseMediaWikiUIEverywhere;
 139                 if ( $wgUseMediaWikiUIEverywhere ) {
 140                         if ( isset( $attrs['class'] ) ) {
 141                                 if ( is_array( $attrs['class'] ) ) {
 142                                         $attrs['class'][] = 'mw-ui-input';
 143                                 } else {
 144                                         $attrs['class'] .= ' mw-ui-input';
 145                                 }
 146                         } else {
 147                                 $attrs['class'] = 'mw-ui-input';
 148                         }
 149                 }
 150                 return $attrs;
 151         }
 152
 153         /**
 154          * Returns an HTML link element in a string styled as a button
 155          * (when $wgUseMediaWikiUIEverywhere is enabled).
 156          *
 157          * @param string $contents The raw HTML contents of the element: *not*
 158          *   escaped!
 159          * @param array $attrs Associative array of attributes, e.g., [
 160          *   'href' => 'https://www.mediawiki.org/' ]. See expandAttributes() for
 161          *   further documentation.
 162          * @param string[] $modifiers classes to add to the button
 163          * @see https://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 164          * @return string Raw HTML
 165          */
 166         public static function linkButton( $contents, array $attrs, array $modifiers = [] ) {
 167                 return self::element( 'a',
 168                         self::buttonAttributes( $attrs, $modifiers ),
 169                         $contents
 170                 );
 171         }
 172
 173         /**
 174          * Returns an HTML link element in a string styled as a button
 175          * (when $wgUseMediaWikiUIEverywhere is enabled).
 176          *
 177          * @param string $contents The raw HTML contents of the element: *not*
 178          *   escaped!
 179          * @param array $attrs Associative array of attributes, e.g., [
 180          *   'href' => 'https://www.mediawiki.org/' ]. See expandAttributes() for
 181          *   further documentation.
 182          * @param string[] $modifiers classes to add to the button
 183          * @see https://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 184          * @return string Raw HTML
 185          */
 186         public static function submitButton( $contents, array $attrs, array $modifiers = [] ) {
 187                 $attrs['type'] = 'submit';
 188                 $attrs['value'] = $contents;
 189                 return self::element( 'input', self::buttonAttributes( $attrs, $modifiers ) );
 190         }
 191
 192         /**
 193          * Returns an HTML element in a string.  The major advantage here over
 194          * manually typing out the HTML is that it will escape all attribute
 195          * values.
 196          *
 197          * This is quite similar to Xml::tags(), but it implements some useful
 198          * HTML-specific logic.  For instance, there is no $allowShortTag
 199          * parameter: the closing tag is magically omitted if $element has an empty
 200          * content model.
 201          *
 202          * @param string $element The element's name, e.g., 'a'
 203          * @param array $attribs Associative array of attributes, e.g., [
 204          *   'href' => 'https://www.mediawiki.org/' ]. See expandAttributes() for
 205          *   further documentation.
 206          * @param string $contents The raw HTML contents of the element: *not*
 207          *   escaped!
 208          * @return string Raw HTML
 209          */
 210         public static function rawElement( $element, $attribs = [], $contents = '' ) {
 211                 $start = self::openElement( $element, $attribs );
 212                 if ( in_array( $element, self::$voidElements ) ) {
 213                         // Silly XML.
 214                         return substr( $start, 0, -1 ) . '/>';
 215                 } else {
 216                         return "$start$contents" . self::closeElement( $element );
 217                 }
 218         }
 219
 220         /**
 221          * Identical to rawElement(), but HTML-escapes $contents (like
 222          * Xml::element()).
 223          *
 224          * @param string $element Name of the element, e.g., 'a'
 225          * @param array $attribs Associative array of attributes, e.g., [
 226          *   'href' => 'https://www.mediawiki.org/' ]. See expandAttributes() for
 227          *   further documentation.
 228          * @param string $contents
 229          *
 230          * @return string
 231          */
 232         public static function element( $element, $attribs = [], $contents = '' ) {
 233                 return self::rawElement( $element, $attribs, strtr( $contents, [
 234                         // There's no point in escaping quotes, >, etc. in the contents of
 235                         // elements.
 236                         '&' => '&amp;',
 237                         '<' => '&lt;'
 238                 ] ) );
 239         }
 240
 241         /**
 242          * Identical to rawElement(), but has no third parameter and omits the end
 243          * tag (and the self-closing '/' in XML mode for empty elements).
 244          *
 245          * @param string $element Name of the element, e.g., 'a'
 246          * @param array $attribs Associative array of attributes, e.g., [
 247          *   'href' => 'https://www.mediawiki.org/' ]. See expandAttributes() for
 248          *   further documentation.
 249          *
 250          * @return string
 251          */
 252         public static function openElement( $element, $attribs = [] ) {
 253                 $attribs = (array)$attribs;
 254                 // This is not required in HTML5, but let's do it anyway, for
 255                 // consistency and better compression.
 256                 $element = strtolower( $element );
 257
 258                 // Some people were abusing this by passing things like
 259                 // 'h1 id="foo" to $element, which we don't want.
 260                 if ( strpos( $element, ' ' ) !== false ) {
 261                         wfWarn( __METHOD__ . " given element name with space '$element'" );
 262                 }
 263
 264                 // Remove invalid input types
 265                 if ( $element == 'input' ) {
 266                         $validTypes = [
 267                                 'hidden',
 268                                 'text',
 269                                 'password',
 270                                 'checkbox',
 271                                 'radio',
 272                                 'file',
 273                                 'submit',
 274                                 'image',
 275                                 'reset',
 276                                 'button',
 277
 278                                 // HTML input types
 279                                 'datetime',
 280                                 'datetime-local',
 281                                 'date',
 282                                 'month',
 283                                 'time',
 284                                 'week',
 285                                 'number',
 286                                 'range',
 287                                 'email',
 288                                 'url',
 289                                 'search',
 290                                 'tel',
 291                                 'color',
 292                         ];
 293                         if ( isset( $attribs['type'] ) && !in_array( $attribs['type'], $validTypes ) ) {
 294                                 unset( $attribs['type'] );
 295                         }
 296                 }
 297
 298                 // According to standard the default type for <button> elements is "submit".
 299                 // Depending on compatibility mode IE might use "button", instead.
 300                 // We enforce the standard "submit".
 301                 if ( $element == 'button' && !isset( $attribs['type'] ) ) {
 302                         $attribs['type'] = 'submit';
 303                 }
 304
 305                 return "<$element" . self::expandAttributes(
 306                         self::dropDefaults( $element, $attribs ) ) . '>';
 307         }
 308
 309         /**
 310          * Returns "</$element>"
 311          *
 312          * @since 1.17
 313          * @param string $element Name of the element, e.g., 'a'
 314          * @return string A closing tag
 315          */
 316         public static function closeElement( $element ) {
 317                 $element = strtolower( $element );
 318
 319                 return "</$element>";
 320         }
 321
 322         /**
 323          * Given an element name and an associative array of element attributes,
 324          * return an array that is functionally identical to the input array, but
 325          * possibly smaller.  In particular, attributes might be stripped if they
 326          * are given their default values.
 327          *
 328          * This method is not guaranteed to remove all redundant attributes, only
 329          * some common ones and some others selected arbitrarily at random.  It
 330          * only guarantees that the output array should be functionally identical
 331          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 332          *
 333          * @param string $element Name of the element, e.g., 'a'
 334          * @param array $attribs Associative array of attributes, e.g., [
 335          *   'href' => 'https://www.mediawiki.org/' ].  See expandAttributes() for
 336          *   further documentation.
 337          * @return array An array of attributes functionally identical to $attribs
 338          */
 339         private static function dropDefaults( $element, array $attribs ) {
 340                 // Whenever altering this array, please provide a covering test case
 341                 // in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 342                 static $attribDefaults = [
 343                         'area' => [ 'shape' => 'rect' ],
 344                         'button' => [
 345                                 'formaction' => 'GET',
 346                                 'formenctype' => 'application/x-www-form-urlencoded',
 347                         ],
 348                         'canvas' => [
 349                                 'height' => '150',
 350                                 'width' => '300',
 351                         ],
 352                         'form' => [
 353                                 'action' => 'GET',
 354                                 'autocomplete' => 'on',
 355                                 'enctype' => 'application/x-www-form-urlencoded',
 356                         ],
 357                         'input' => [
 358                                 'formaction' => 'GET',
 359                                 'type' => 'text',
 360                         ],
 361                         'keygen' => [ 'keytype' => 'rsa' ],
 362                         'link' => [ 'media' => 'all' ],
 363                         'menu' => [ 'type' => 'list' ],
 364                         'script' => [ 'type' => 'text/javascript' ],
 365                         'style' => [
 366                                 'media' => 'all',
 367                                 'type' => 'text/css',
 368                         ],
 369                         'textarea' => [ 'wrap' => 'soft' ],
 370                 ];
 371
 372                 $element = strtolower( $element );
 373
 374                 foreach ( $attribs as $attrib => $value ) {
 375                         $lcattrib = strtolower( $attrib );
 376                         if ( is_array( $value ) ) {
 377                                 $value = implode( ' ', $value );
 378                         } else {
 379                                 $value = strval( $value );
 380                         }
 381
 382                         // Simple checks using $attribDefaults
 383                         if ( isset( $attribDefaults[$element][$lcattrib] )
 384                                 && $attribDefaults[$element][$lcattrib] == $value
 385                         ) {
 386                                 unset( $attribs[$attrib] );
 387                         }
 388
 389                         if ( $lcattrib == 'class' && $value == '' ) {
 390                                 unset( $attribs[$attrib] );
 391                         }
 392                 }
 393
 394                 // More subtle checks
 395                 if ( $element === 'link'
 396                         && isset( $attribs['type'] ) && strval( $attribs['type'] ) == 'text/css'
 397                 ) {
 398                         unset( $attribs['type'] );
 399                 }
 400                 if ( $element === 'input' ) {
 401                         $type = $attribs['type'] ?? null;
 402                         $value = $attribs['value'] ?? null;
 403                         if ( $type === 'checkbox' || $type === 'radio' ) {
 404                                 // The default value for checkboxes and radio buttons is 'on'
 405                                 // not ''. By stripping value="" we break radio boxes that
 406                                 // actually wants empty values.
 407                                 if ( $value === 'on' ) {
 408                                         unset( $attribs['value'] );
 409                                 }
 410                         } elseif ( $type === 'submit' ) {
 411                                 // The default value for submit appears to be "Submit" but
 412                                 // let's not bother stripping out localized text that matches
 413                                 // that.
 414                         } else {
 415                                 // The default value for nearly every other field type is ''
 416                                 // The 'range' and 'color' types use different defaults but
 417                                 // stripping a value="" does not hurt them.
 418                                 if ( $value === '' ) {
 419                                         unset( $attribs['value'] );
 420                                 }
 421                         }
 422                 }
 423                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 424                         if ( in_array( 'multiple', $attribs )
 425                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 426                         ) {
 427                                 // A multi-select
 428                                 if ( strval( $attribs['size'] ) == '4' ) {
 429                                         unset( $attribs['size'] );
 430                                 }
 431                         } else {
 432                                 // Single select
 433                                 if ( strval( $attribs['size'] ) == '1' ) {
 434                                         unset( $attribs['size'] );
 435                                 }
 436                         }
 437                 }
 438
 439                 return $attribs;
 440         }
 441
 442         /**
 443          * Given an associative array of element attributes, generate a string
 444          * to stick after the element name in HTML output.  Like [ 'href' =>
 445          * 'https://www.mediawiki.org/' ] becomes something like
 446          * ' href="https://www.mediawiki.org"'.  Again, this is like
 447          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 448          *
 449          * Attributes that can contain space-separated lists ('class', 'accesskey' and 'rel') array
 450          * values are allowed as well, which will automagically be normalized
 451          * and converted to a space-separated string. In addition to a numerical
 452          * array, the attribute value may also be an associative array. See the
 453          * example below for how that works.
 454          *
 455          * @par Numerical array
 456          * @code
 457          *     Html::element( 'em', [
 458          *         'class' => [ 'foo', 'bar' ]
 459          *     ] );
 460          *     // gives '<em class="foo bar"></em>'
 461          * @endcode
 462          *
 463          * @par Associative array
 464          * @code
 465          *     Html::element( 'em', [
 466          *         'class' => [ 'foo', 'bar', 'foo' => false, 'quux' => true ]
 467          *     ] );
 468          *     // gives '<em class="bar quux"></em>'
 469          * @endcode
 470          *
 471          * @param array $attribs Associative array of attributes, e.g., [
 472          *   'href' => 'https://www.mediawiki.org/' ].  Values will be HTML-escaped.
 473          *   A value of false or null means to omit the attribute.  For boolean attributes,
 474          *   you can omit the key, e.g., [ 'checked' ] instead of
 475          *   [ 'checked' => 'checked' ] or such.
 476          *
 477          * @throws MWException If an attribute that doesn't allow lists is set to an array
 478          * @return string HTML fragment that goes between element name and '>'
 479          *   (starting with a space if at least one attribute is output)
 480          */
 481         public static function expandAttributes( array $attribs ) {
 482                 $ret = '';
 483                 foreach ( $attribs as $key => $value ) {
 484                         // Support intuitive [ 'checked' => true/false ] form
 485                         if ( $value === false || is_null( $value ) ) {
 486                                 continue;
 487                         }
 488
 489                         // For boolean attributes, support [ 'foo' ] instead of
 490                         // requiring [ 'foo' => 'meaningless' ].
 491                         if ( is_int( $key ) && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 492                                 $key = $value;
 493                         }
 494
 495                         // Not technically required in HTML5 but we'd like consistency
 496                         // and better compression anyway.
 497                         $key = strtolower( $key );
 498
 499                         // https://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 500                         // https://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 501                         $spaceSeparatedListAttributes = [
 502                                 'class', // html4, html5
 503                                 'accesskey', // as of html5, multiple space-separated values allowed
 504                                 // html4-spec doesn't document rel= as space-separated
 505                                 // but has been used like that and is now documented as such
 506                                 // in the html5-spec.
 507                                 'rel',
 508                         ];
 509
 510                         // Specific features for attributes that allow a list of space-separated values
 511                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 512                                 // Apply some normalization and remove duplicates
 513
 514                                 // Convert into correct array. Array can contain space-separated
 515                                 // values. Implode/explode to get those into the main array as well.
 516                                 if ( is_array( $value ) ) {
 517                                         // If input wasn't an array, we can skip this step
 518                                         $newValue = [];
 519                                         foreach ( $value as $k => $v ) {
 520                                                 if ( is_string( $v ) ) {
 521                                                         // String values should be normal `array( 'foo' )`
 522                                                         // Just append them
 523                                                         if ( !isset( $value[$v] ) ) {
 524                                                                 // As a special case don't set 'foo' if a
 525                                                                 // separate 'foo' => true/false exists in the array
 526                                                                 // keys should be authoritative
 527                                                                 $newValue[] = $v;
 528                                                         }
 529                                                 } elseif ( $v ) {
 530                                                         // If the value is truthy but not a string this is likely
 531                                                         // an [ 'foo' => true ], falsy values don't add strings
 532                                                         $newValue[] = $k;
 533                                                 }
 534                                         }
 535                                         $value = implode( ' ', $newValue );
 536                                 }
 537                                 $value = explode( ' ', $value );
 538
 539                                 // Normalize spacing by fixing up cases where people used
 540                                 // more than 1 space and/or a trailing/leading space
 541                                 $value = array_diff( $value, [ '', ' ' ] );
 542
 543                                 // Remove duplicates and create the string
 544                                 $value = implode( ' ', array_unique( $value ) );
 545                         } elseif ( is_array( $value ) ) {
 546                                 throw new MWException( "HTML attribute $key can not contain a list of values" );
 547                         }
 548
 549                         $quote = '"';
 550
 551                         if ( in_array( $key, self::$boolAttribs ) ) {
 552                                 $ret .= " $key=\"\"";
 553                         } else {
 554                                 $ret .= " $key=$quote" . Sanitizer::encodeAttribute( $value ) . $quote;
 555                         }
 556                 }
 557                 return $ret;
 558         }
 559
 560         /**
 561          * Output an HTML script tag with the given contents.
 562          *
 563          * It is unsupported for the contents to contain the sequence `<script` or `</script`
 564          * (case-insensitive). This ensures the script can be terminated easily and consistently.
 565          * It is the responsibility of the caller to avoid such character sequence by escaping
 566          * or avoiding it. If found at run-time, the contents are replaced with a comment, and
 567          * a warning is logged server-side.
 568          *
 569          * @param string $contents JavaScript
 570          * @param string|null $nonce Nonce for CSP header, from OutputPage::getCSPNonce()
 571          * @return string Raw HTML
 572          */
 573         public static function inlineScript( $contents, $nonce = null ) {
 574                 $attrs = [];
 575                 if ( $nonce !== null ) {
 576                         $attrs['nonce'] = $nonce;
 577                 } else {
 578                         if ( ContentSecurityPolicy::isNonceRequired( RequestContext::getMain()->getConfig() ) ) {
 579                                 wfWarn( "no nonce set on script. CSP will break it" );
 580                         }
 581                 }
 582
 583                 if ( preg_match( '/<\/?script/i', $contents ) ) {
 584                         wfLogWarning( __METHOD__ . ': Illegal character sequence found in inline script.' );
 585                         $contents = '/* ERROR: Invalid script */';
 586                 }
 587
 588                 return self::rawElement( 'script', $attrs, $contents );
 589         }
 590
 591         /**
 592          * Output a "<script>" tag linking to the given URL, e.g.,
 593          * "<script src=foo.js></script>".
 594          *
 595          * @param string $url
 596          * @param string|null $nonce Nonce for CSP header, from OutputPage::getCSPNonce()
 597          * @return string Raw HTML
 598          */
 599         public static function linkedScript( $url, $nonce = null ) {
 600                 $attrs = [ 'src' => $url ];
 601                 if ( $nonce !== null ) {
 602                         $attrs['nonce'] = $nonce;
 603                 } else {
 604                         if ( ContentSecurityPolicy::isNonceRequired( RequestContext::getMain()->getConfig() ) ) {
 605                                 wfWarn( "no nonce set on script. CSP will break it" );
 606                         }
 607                 }
 608
 609                 return self::element( 'script', $attrs );
 610         }
 611
 612         /**
 613          * Output a "<style>" tag with the given contents for the given media type
 614          * (if any).  TODO: do some useful escaping as well, like if $contents
 615          * contains literal "</style>" (admittedly unlikely).
 616          *
 617          * @param string $contents CSS
 618          * @param string $media A media type string, like 'screen'
 619          * @param array $attribs (since 1.31) Associative array of attributes, e.g., [
 620          *   'href' => 'https://www.mediawiki.org/' ]. See expandAttributes() for
 621          *   further documentation.
 622          * @return string Raw HTML
 623          */
 624         public static function inlineStyle( $contents, $media = 'all', $attribs = [] ) {
 625                 // Don't escape '>' since that is used
 626                 // as direct child selector.
 627                 // Remember, in css, there is no "x" for hexadecimal escapes, and
 628                 // the space immediately after an escape sequence is swallowed.
 629                 $contents = strtr( $contents, [
 630                         '<' => '\3C ',
 631                         // CDATA end tag for good measure, but the main security
 632                         // is from escaping the '<'.
 633                         ']]>' => '\5D\5D\3E '
 634                 ] );
 635
 636                 if ( preg_match( '/[<&]/', $contents ) ) {
 637                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 638                 }
 639
 640                 return self::rawElement( 'style', [
 641                         'media' => $media,
 642                 ] + $attribs, $contents );
 643         }
 644
 645         /**
 646          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 647          * media type (if any).
 648          *
 649          * @param string $url
 650          * @param string $media A media type string, like 'screen'
 651          * @return string Raw HTML
 652          */
 653         public static function linkedStyle( $url, $media = 'all' ) {
 654                 return self::element( 'link', [
 655                         'rel' => 'stylesheet',
 656                         'href' => $url,
 657                         'media' => $media,
 658                 ] );
 659         }
 660
 661         /**
 662          * Convenience function to produce an "<input>" element.  This supports the
 663          * new HTML5 input types and attributes.
 664          *
 665          * @param string $name Name attribute
 666          * @param string $value Value attribute
 667          * @param string $type Type attribute
 668          * @param array $attribs Associative array of miscellaneous extra
 669          *   attributes, passed to Html::element()
 670          * @return string Raw HTML
 671          */
 672         public static function input( $name, $value = '', $type = 'text', array $attribs = [] ) {
 673                 $attribs['type'] = $type;
 674                 $attribs['value'] = $value;
 675                 $attribs['name'] = $name;
 676                 if ( in_array( $type, [ 'text', 'search', 'email', 'password', 'number' ] ) ) {
 677                         $attribs = self::getTextInputAttributes( $attribs );
 678                 }
 679                 if ( in_array( $type, [ 'button', 'reset', 'submit' ] ) ) {
 680                         $attribs = self::buttonAttributes( $attribs );
 681                 }
 682                 return self::element( 'input', $attribs );
 683         }
 684
 685         /**
 686          * Convenience function to produce a checkbox (input element with type=checkbox)
 687          *
 688          * @param string $name Name attribute
 689          * @param bool $checked Whether the checkbox is checked or not
 690          * @param array $attribs Array of additional attributes
 691          * @return string Raw HTML
 692          */
 693         public static function check( $name, $checked = false, array $attribs = [] ) {
 694                 if ( isset( $attribs['value'] ) ) {
 695                         $value = $attribs['value'];
 696                         unset( $attribs['value'] );
 697                 } else {
 698                         $value = 1;
 699                 }
 700
 701                 if ( $checked ) {
 702                         $attribs[] = 'checked';
 703                 }
 704
 705                 return self::input( $name, $value, 'checkbox', $attribs );
 706         }
 707
 708         /**
 709          * Return the HTML for a message box.
 710          * @since 1.31
 711          * @param string $html of contents of box
 712          * @param string $className corresponding to box
 713          * @param string $heading (optional)
 714          * @return string of HTML representing a box.
 715          */
 716         private static function messageBox( $html, $className, $heading = '' ) {
 717                 if ( $heading !== '' ) {
 718                         $html = self::element( 'h2', [], $heading ) . $html;
 719                 }
 720                 return self::rawElement( 'div', [ 'class' => $className ], $html );
 721         }
 722
 723         /**
 724          * Return a warning box.
 725          * @since 1.31
 726          * @param string $html of contents of box
 727          * @return string of HTML representing a warning box.
 728          */
 729         public static function warningBox( $html ) {
 730                 return self::messageBox( $html, 'warningbox' );
 731         }
 732
 733         /**
 734          * Return an error box.
 735          * @since 1.31
 736          * @param string $html of contents of error box
 737          * @param string $heading (optional)
 738          * @return string of HTML representing an error box.
 739          */
 740         public static function errorBox( $html, $heading = '' ) {
 741                 return self::messageBox( $html, 'errorbox', $heading );
 742         }
 743
 744         /**
 745          * Return a success box.
 746          * @since 1.31
 747          * @param string $html of contents of box
 748          * @return string of HTML representing a success box.
 749          */
 750         public static function successBox( $html ) {
 751                 return self::messageBox( $html, 'successbox' );
 752         }
 753
 754         /**
 755          * Convenience function to produce a radio button (input element with type=radio)
 756          *
 757          * @param string $name Name attribute
 758          * @param bool $checked Whether the radio button is checked or not
 759          * @param array $attribs Array of additional attributes
 760          * @return string Raw HTML
 761          */
 762         public static function radio( $name, $checked = false, array $attribs = [] ) {
 763                 if ( isset( $attribs['value'] ) ) {
 764                         $value = $attribs['value'];
 765                         unset( $attribs['value'] );
 766                 } else {
 767                         $value = 1;
 768                 }
 769
 770                 if ( $checked ) {
 771                         $attribs[] = 'checked';
 772                 }
 773
 774                 return self::input( $name, $value, 'radio', $attribs );
 775         }
 776
 777         /**
 778          * Convenience function for generating a label for inputs.
 779          *
 780          * @param string $label Contents of the label
 781          * @param string $id ID of the element being labeled
 782          * @param array $attribs Additional attributes
 783          * @return string Raw HTML
 784          */
 785         public static function label( $label, $id, array $attribs = [] ) {
 786                 $attribs += [
 787                         'for' => $id
 788                 ];
 789                 return self::element( 'label', $attribs, $label );
 790         }
 791
 792         /**
 793          * Convenience function to produce an input element with type=hidden
 794          *
 795          * @param string $name Name attribute
 796          * @param string $value Value attribute
 797          * @param array $attribs Associative array of miscellaneous extra
 798          *   attributes, passed to Html::element()
 799          * @return string Raw HTML
 800          */
 801         public static function hidden( $name, $value, array $attribs = [] ) {
 802                 return self::input( $name, $value, 'hidden', $attribs );
 803         }
 804
 805         /**
 806          * Convenience function to produce a <textarea> element.
 807          *
 808          * This supports leaving out the cols= and rows= which Xml requires and are
 809          * required by HTML4/XHTML but not required by HTML5.
 810          *
 811          * @param string $name Name attribute
 812          * @param string $value Value attribute
 813          * @param array $attribs Associative array of miscellaneous extra
 814          *   attributes, passed to Html::element()
 815          * @return string Raw HTML
 816          */
 817         public static function textarea( $name, $value = '', array $attribs = [] ) {
 818                 $attribs['name'] = $name;
 819
 820                 if ( substr( $value, 0, 1 ) == "\n" ) {
 821                         // Workaround for T14130: browsers eat the initial newline
 822                         // assuming that it's just for show, but they do keep the later
 823                         // newlines, which we may want to preserve during editing.
 824                         // Prepending a single newline
 825                         $spacedValue = "\n" . $value;
 826                 } else {
 827                         $spacedValue = $value;
 828                 }
 829                 return self::element( 'textarea', self::getTextInputAttributes( $attribs ), $spacedValue );
 830         }
 831
 832         /**
 833          * Helper for Html::namespaceSelector().
 834          * @param array $params See Html::namespaceSelector()
 835          * @return array
 836          */
 837         public static function namespaceSelectorOptions( array $params = [] ) {
 838                 $options = [];
 839
 840                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 841                         $params['exclude'] = [];
 842                 }
 843
 844                 if ( isset( $params['all'] ) ) {
 845                         // add an option that would let the user select all namespaces.
 846                         // Value is provided by user, the name shown is localized for the user.
 847                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 848                 }
 849                 if ( $params['in-user-lang'] ?? false ) {
 850                         global $wgLang;
 851                         $lang = $wgLang;
 852                 } else {
 853                         $lang = MediaWikiServices::getInstance()->getContentLanguage();
 854                 }
 855                 // Add all namespaces as options
 856                 $options += $lang->getFormattedNamespaces();
 857
 858                 $optionsOut = [];
 859                 // Filter out namespaces below 0 and massage labels
 860                 foreach ( $options as $nsId => $nsName ) {
 861                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 862                                 continue;
 863                         }
 864                         if ( $nsId === NS_MAIN ) {
 865                                 // For other namespaces use the namespace prefix as label, but for
 866                                 // main we don't use "" but the user message describing it (e.g. "(Main)" or "(Article)")
 867                                 $nsName = wfMessage( 'blanknamespace' )->text();
 868                         } elseif ( is_int( $nsId ) ) {
 869                                 $nsName = $lang->convertNamespace( $nsId );
 870                         }
 871                         $optionsOut[$nsId] = $nsName;
 872                 }
 873
 874                 return $optionsOut;
 875         }
 876
 877         /**
 878          * Build a drop-down box for selecting a namespace
 879          *
 880          * @param array $params Params to set.
 881          * - selected: [optional] Id of namespace which should be pre-selected
 882          * - all: [optional] Value of item for "all namespaces". If null or unset,
 883          *   no "<option>" is generated to select all namespaces.
 884          * - label: text for label to add before the field.
 885          * - exclude: [optional] Array of namespace ids to exclude.
 886          * - disable: [optional] Array of namespace ids for which the option should
 887          *   be disabled in the selector.
 888          * @param array $selectAttribs HTML attributes for the generated select element.
 889          * - id:   [optional], default: 'namespace'.
 890          * - name: [optional], default: 'namespace'.
 891          * @return string HTML code to select a namespace.
 892          */
 893         public static function namespaceSelector( array $params = [],
 894                 array $selectAttribs = []
 895         ) {
 896                 ksort( $selectAttribs );
 897
 898                 // Is a namespace selected?
 899                 if ( isset( $params['selected'] ) ) {
 900                         // If string only contains digits, convert to clean int. Selected could also
 901                         // be "all" or "" etc. which needs to be left untouched.
 902                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 903                         // and returns false for already clean ints. Use regex instead..
 904                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 905                                 $params['selected'] = intval( $params['selected'] );
 906                         }
 907                         // else: leaves it untouched for later processing
 908                 } else {
 909                         $params['selected'] = '';
 910                 }
 911
 912                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 913                         $params['disable'] = [];
 914                 }
 915
 916                 // Associative array between option-values and option-labels
 917                 $options = self::namespaceSelectorOptions( $params );
 918
 919                 // Convert $options to HTML
 920                 $optionsHtml = [];
 921                 foreach ( $options as $nsId => $nsName ) {
 922                         $optionsHtml[] = self::element(
 923                                 'option', [
 924                                         'disabled' => in_array( $nsId, $params['disable'] ),
 925                                         'value' => $nsId,
 926                                         'selected' => $nsId === $params['selected'],
 927                                 ], $nsName
 928                         );
 929                 }
 930
 931                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 932                         $selectAttribs['id'] = 'namespace';
 933                 }
 934
 935                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 936                         $selectAttribs['name'] = 'namespace';
 937                 }
 938
 939                 $ret = '';
 940                 if ( isset( $params['label'] ) ) {
 941                         $ret .= self::element(
 942                                 'label', [
 943                                         'for' => $selectAttribs['id'] ?? null,
 944                                 ], $params['label']
 945                         ) . "\u{00A0}";
 946                 }
 947
 948                 // Wrap options in a <select>
 949                 $ret .= self::openElement( 'select', $selectAttribs )
 950                         . "\n"
 951                         . implode( "\n", $optionsHtml )
 952                         . "\n"
 953                         . self::closeElement( 'select' );
 954
 955                 return $ret;
 956         }
 957
 958         /**
 959          * Constructs the opening html-tag with necessary doctypes depending on
 960          * global variables.
 961          *
 962          * @param array $attribs Associative array of miscellaneous extra
 963          *   attributes, passed to Html::element() of html tag.
 964          * @return string Raw HTML
 965          */
 966         public static function htmlHeader( array $attribs = [] ) {
 967                 $ret = '';
 968
 969                 global $wgHtml5Version, $wgMimeType, $wgXhtmlNamespaces;
 970
 971                 $isXHTML = self::isXmlMimeType( $wgMimeType );
 972
 973                 if ( $isXHTML ) { // XHTML5
 974                         // XML MIME-typed markup should have an xml header.
 975                         // However a DOCTYPE is not needed.
 976                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 977
 978                         // Add the standard xmlns
 979                         $attribs['xmlns'] = 'http://www.w3.org/1999/xhtml';
 980
 981                         // And support custom namespaces
 982                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 983                                 $attribs["xmlns:$tag"] = $ns;
 984                         }
 985                 } else { // HTML5
 986                         // DOCTYPE
 987                         $ret .= "<!DOCTYPE html>\n";
 988                 }
 989
 990                 if ( $wgHtml5Version ) {
 991                         $attribs['version'] = $wgHtml5Version;
 992                 }
 993
 994                 $ret .= self::openElement( 'html', $attribs );
 995
 996                 return $ret;
 997         }
 998
 999         /**
1000          * Determines if the given MIME type is xml.
1001          *
1002          * @param string $mimetype MIME type
1003          * @return bool
1004          */
1005         public static function isXmlMimeType( $mimetype ) {
1006                 # https://html.spec.whatwg.org/multipage/infrastructure.html#xml-mime-type
1007                 # * text/xml
1008                 # * application/xml
1009                 # * Any MIME type with a subtype ending in +xml (this implicitly includes application/xhtml+xml)
1010                 return (bool)preg_match( '!^(text|application)/xml$|^.+/.+\+xml$!', $mimetype );
1011         }
1012
1013         /**
1014          * Get HTML for an info box with an icon.
1015          *
1016          * @param string $text Wikitext, get this with wfMessage()->plain()
1017          * @param string $icon Path to icon file (used as 'src' attribute)
1018          * @param string $alt Alternate text for the icon
1019          * @param string $class Additional class name to add to the wrapper div
1020          *
1021          * @return string
1022          */
1023         static function infoBox( $text, $icon, $alt, $class = '' ) {
1024                 $s = self::openElement( 'div', [ 'class' => "mw-infobox $class" ] );
1025
1026                 $s .= self::openElement( 'div', [ 'class' => 'mw-infobox-left' ] ) .
1027                                 self::element( 'img',
1028                                         [
1029                                                 'src' => $icon,
1030                                                 'alt' => $alt,
1031                                         ]
1032                                 ) .
1033                                 self::closeElement( 'div' );
1034
1035                 $s .= self::openElement( 'div', [ 'class' => 'mw-infobox-right' ] ) .
1036                                 $text .
1037                                 self::closeElement( 'div' );
1038                 $s .= self::element( 'div', [ 'style' => 'clear: left;' ], ' ' );
1039
1040                 $s .= self::closeElement( 'div' );
1041
1042                 $s .= self::element( 'div', [ 'style' => 'clear: left;' ], ' ' );
1043
1044                 return $s;
1045         }
1046
1047         /**
1048          * Generate a srcset attribute value.
1049          *
1050          * Generates a srcset attribute value from an array mapping pixel densities
1051          * to URLs. A trailing 'x' in pixel density values is optional.
1052          *
1053          * @note srcset width and height values are not supported.
1054          *
1055          * @see https://html.spec.whatwg.org/#attr-img-srcset
1056          *
1057          * @par Example:
1058          * @code
1059          *     Html::srcSet( [
1060          *         '1x'   => 'standard.jpeg',
1061          *         '1.5x' => 'large.jpeg',
1062          *         '3x'   => 'extra-large.jpeg',
1063          *     ] );
1064          *     // gives 'standard.jpeg 1x, large.jpeg 1.5x, extra-large.jpeg 2x'
1065          * @endcode
1066          *
1067          * @param string[] $urls
1068          * @return string
1069          */
1070         static function srcSet( array $urls ) {
1071                 $candidates = [];
1072                 foreach ( $urls as $density => $url ) {
1073                         // Cast density to float to strip 'x', then back to string to serve
1074                         // as array index.
1075                         $density = (string)(float)$density;
1076                         $candidates[$density] = $url;
1077                 }
1078
1079                 // Remove duplicates that are the same as a smaller value
1080                 ksort( $candidates, SORT_NUMERIC );
1081                 $candidates = array_unique( $candidates );
1082
1083                 // Append density info to the url
1084                 foreach ( $candidates as $density => $url ) {
1085                         $candidates[$density] = $url . ' ' . $density . 'x';
1086                 }
1087
1088                 return implode( ", ", $candidates );
1089         }
1090 }