includes/Html.php

   1 <?php
   2 /**
   3  * Collection of methods to generate HTML content
   4  *
   5  * Copyright © 2009 Aryeh Gregor
   6  * http://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
  26 /**
  27  * This class is a collection of static functions that serve two purposes:
  28  *
  29  * 1) Implement any algorithms specified by HTML5, or other HTML
  30  * specifications, in a convenient and self-contained way.
  31  *
  32  * 2) Allow HTML elements to be conveniently and safely generated, like the
  33  * current Xml class but a) less confused (Xml supports HTML-specific things,
  34  * but only sometimes!) and b) not necessarily confined to XML-compatible
  35  * output.
  36  *
  37  * There are two important configuration options this class uses:
  38  *
  39  * $wgMimeType: If this is set to an xml MIME type then output should be
  40  *     valid XHTML5.
  41  * $wgWellFormedXml: If this is set to true, then all output should be
  42  *     well-formed XML (quotes on attributes, self-closing tags, etc.).
  43  *
  44  * This class is meant to be confined to utility functions that are called from
  45  * trusted code paths.  It does not do enforcement of policy like not allowing
  46  * <a> elements.
  47  *
  48  * @since 1.16
  49  */
  50 class Html {
  51         // List of void elements from HTML5, section 8.1.2 as of 2011-08-12
  52         private static $voidElements = array(
  53                 'area',
  54                 'base',
  55                 'br',
  56                 'col',
  57                 'command',
  58                 'embed',
  59                 'hr',
  60                 'img',
  61                 'input',
  62                 'keygen',
  63                 'link',
  64                 'meta',
  65                 'param',
  66                 'source',
  67                 'track',
  68                 'wbr',
  69         );
  70
  71         // Boolean attributes, which may have the value omitted entirely.  Manually
  72         // collected from the HTML5 spec as of 2011-08-12.
  73         private static $boolAttribs = array(
  74                 'async',
  75                 'autofocus',
  76                 'autoplay',
  77                 'checked',
  78                 'controls',
  79                 'default',
  80                 'defer',
  81                 'disabled',
  82                 'formnovalidate',
  83                 'hidden',
  84                 'ismap',
  85                 'itemscope',
  86                 'loop',
  87                 'multiple',
  88                 'muted',
  89                 'novalidate',
  90                 'open',
  91                 'pubdate',
  92                 'readonly',
  93                 'required',
  94                 'reversed',
  95                 'scoped',
  96                 'seamless',
  97                 'selected',
  98                 'truespeed',
  99                 'typemustmatch',
 100                 // HTML5 Microdata
 101                 'itemscope',
 102         );
 103
 104         /**
 105          * Modifies a set of attributes meant for button elements
 106          * and apply a set of default attributes when $wgUseMediaWikiUIEverywhere enabled.
 107          * @param array $attrs
 108          * @param string[] $modifiers to add to the button
 109          * @see https://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 110          * @return array $attrs A modified attribute array
 111          */
 112         public static function buttonAttributes( array $attrs, array $modifiers = array() ) {
 113                 global $wgUseMediaWikiUIEverywhere;
 114                 if ( $wgUseMediaWikiUIEverywhere ) {
 115                         if ( isset( $attrs['class'] ) ) {
 116                                 if ( is_array( $attrs['class'] ) ) {
 117                                         $attrs['class'][] = 'mw-ui-button';
 118                                         $attrs = array_merge( $attrs, $modifiers );
 119                                         // ensure compatibility with Xml
 120                                         $attrs['class'] = implode( ' ', $attrs['class'] );
 121                                 } else {
 122                                         $attrs['class'] .= ' mw-ui-button ' . implode( ' ', $modifiers );
 123                                 }
 124                         } else {
 125                                 $attrs['class'] = array( 'mw-ui-button' );
 126                                 // ensure compatibility with Xml
 127                                 $attrs['class'] = implode( ' ', array_merge( $attrs['class'], $modifiers ) );
 128                         }
 129                 }
 130                 return $attrs;
 131         }
 132
 133         /**
 134          * Modifies a set of attributes meant for text input elements
 135          * and apply a set of default attributes.
 136          * Removes size attribute when $wgUseMediaWikiUIEverywhere enabled.
 137          * @param array $attrs An attribute array.
 138          * @return array $attrs A modified attribute array
 139          */
 140         public static function getTextInputAttributes( array $attrs ) {
 141                 global $wgUseMediaWikiUIEverywhere;
 142                 if ( $wgUseMediaWikiUIEverywhere ) {
 143                         if ( isset( $attrs['class'] ) ) {
 144                                 if ( is_array( $attrs['class'] ) ) {
 145                                         $attrs['class'][] = 'mw-ui-input';
 146                                 } else {
 147                                         $attrs['class'] .= ' mw-ui-input';
 148                                 }
 149                         } else {
 150                                 $attrs['class'] = 'mw-ui-input';
 151                         }
 152                 }
 153                 return $attrs;
 154         }
 155
 156         /**
 157          * Returns an HTML link element in a string styled as a button
 158          * (when $wgUseMediaWikiUIEverywhere is enabled).
 159          *
 160          * @param string $contents The raw HTML contents of the element: *not*
 161          *   escaped!
 162          * @param array $attrs Associative array of attributes, e.g., array(
 163          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 164          *   further documentation.
 165          * @param string[] $modifiers to add to the button
 166          * @see http://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 167          * @return string Raw HTML
 168          */
 169         public static function linkButton( $contents, array $attrs, array $modifiers = array() ) {
 170                 return self::element( 'a',
 171                         self::buttonAttributes( $attrs, $modifiers ),
 172                         $contents
 173                 );
 174         }
 175
 176         /**
 177          * Returns an HTML link element in a string styled as a button
 178          * (when $wgUseMediaWikiUIEverywhere is enabled).
 179          *
 180          * @param string $contents The raw HTML contents of the element: *not*
 181          *   escaped!
 182          * @param array $attrs Associative array of attributes, e.g., array(
 183          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 184          *   further documentation.
 185          * @param string[] $modifiers to add to the button
 186          * @see http://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 187          * @return string Raw HTML
 188          */
 189         public static function submitButton( $contents, array $attrs, array $modifiers = array() ) {
 190                 $attrs['type'] = 'submit';
 191                 $attrs['value'] = $contents;
 192                 return self::element( 'input', self::buttonAttributes( $attrs, $modifiers ) );
 193         }
 194
 195         /**
 196          * Returns an HTML element in a string.  The major advantage here over
 197          * manually typing out the HTML is that it will escape all attribute
 198          * values.
 199          *
 200          * This is quite similar to Xml::tags(), but it implements some useful
 201          * HTML-specific logic.  For instance, there is no $allowShortTag
 202          * parameter: the closing tag is magically omitted if $element has an empty
 203          * content model.  If $wgWellFormedXml is false, then a few bytes will be
 204          * shaved off the HTML output as well.
 205          *
 206          * @param string $element The element's name, e.g., 'a'
 207          * @param array $attribs Associative array of attributes, e.g., array(
 208          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 209          *   further documentation.
 210          * @param string $contents The raw HTML contents of the element: *not*
 211          *   escaped!
 212          * @return string Raw HTML
 213          */
 214         public static function rawElement( $element, $attribs = array(), $contents = '' ) {
 215                 global $wgWellFormedXml;
 216                 $start = self::openElement( $element, $attribs );
 217                 if ( in_array( $element, self::$voidElements ) ) {
 218                         if ( $wgWellFormedXml ) {
 219                                 // Silly XML.
 220                                 return substr( $start, 0, -1 ) . ' />';
 221                         }
 222                         return $start;
 223                 } else {
 224                         return "$start$contents" . self::closeElement( $element );
 225                 }
 226         }
 227
 228         /**
 229          * Identical to rawElement(), but HTML-escapes $contents (like
 230          * Xml::element()).
 231          *
 232          * @param string $element
 233          * @param array $attribs
 234          * @param string $contents
 235          *
 236          * @return string
 237          */
 238         public static function element( $element, $attribs = array(), $contents = '' ) {
 239                 return self::rawElement( $element, $attribs, strtr( $contents, array(
 240                         // There's no point in escaping quotes, >, etc. in the contents of
 241                         // elements.
 242                         '&' => '&amp;',
 243                         '<' => '&lt;'
 244                 ) ) );
 245         }
 246
 247         /**
 248          * Identical to rawElement(), but has no third parameter and omits the end
 249          * tag (and the self-closing '/' in XML mode for empty elements).
 250          *
 251          * @param string $element
 252          * @param array $attribs
 253          *
 254          * @return string
 255          */
 256         public static function openElement( $element, $attribs = array() ) {
 257                 $attribs = (array)$attribs;
 258                 // This is not required in HTML5, but let's do it anyway, for
 259                 // consistency and better compression.
 260                 $element = strtolower( $element );
 261
 262                 // Remove invalid input types
 263                 if ( $element == 'input' ) {
 264                         $validTypes = array(
 265                                 'hidden',
 266                                 'text',
 267                                 'password',
 268                                 'checkbox',
 269                                 'radio',
 270                                 'file',
 271                                 'submit',
 272                                 'image',
 273                                 'reset',
 274                                 'button',
 275
 276                                 // HTML input types
 277                                 'datetime',
 278                                 'datetime-local',
 279                                 'date',
 280                                 'month',
 281                                 'time',
 282                                 'week',
 283                                 'number',
 284                                 'range',
 285                                 'email',
 286                                 'url',
 287                                 'search',
 288                                 'tel',
 289                                 'color',
 290                         );
 291                         if ( isset( $attribs['type'] ) && !in_array( $attribs['type'], $validTypes ) ) {
 292                                 unset( $attribs['type'] );
 293                         }
 294                 }
 295
 296                 // According to standard the default type for <button> elements is "submit".
 297                 // Depending on compatibility mode IE might use "button", instead.
 298                 // We enforce the standard "submit".
 299                 if ( $element == 'button' && !isset( $attribs['type'] ) ) {
 300                         $attribs['type'] = 'submit';
 301                 }
 302
 303                 return "<$element" . self::expandAttributes(
 304                         self::dropDefaults( $element, $attribs ) ) . '>';
 305         }
 306
 307         /**
 308          * Returns "</$element>"
 309          *
 310          * @since 1.17
 311          * @param string $element Name of the element, e.g., 'a'
 312          * @return string A closing tag
 313          */
 314         public static function closeElement( $element ) {
 315                 $element = strtolower( $element );
 316
 317                 return "</$element>";
 318         }
 319
 320         /**
 321          * Given an element name and an associative array of element attributes,
 322          * return an array that is functionally identical to the input array, but
 323          * possibly smaller.  In particular, attributes might be stripped if they
 324          * are given their default values.
 325          *
 326          * This method is not guaranteed to remove all redundant attributes, only
 327          * some common ones and some others selected arbitrarily at random.  It
 328          * only guarantees that the output array should be functionally identical
 329          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 330          *
 331          * @param string $element Name of the element, e.g., 'a'
 332          * @param array $attribs Associative array of attributes, e.g., array(
 333          *   'href' => 'http://www.mediawiki.org/' ).  See expandAttributes() for
 334          *   further documentation.
 335          * @return array An array of attributes functionally identical to $attribs
 336          */
 337         private static function dropDefaults( $element, array $attribs ) {
 338                 // Whenever altering this array, please provide a covering test case
 339                 // in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 340                 static $attribDefaults = array(
 341                         'area' => array( 'shape' => 'rect' ),
 342                         'button' => array(
 343                                 'formaction' => 'GET',
 344                                 'formenctype' => 'application/x-www-form-urlencoded',
 345                         ),
 346                         'canvas' => array(
 347                                 'height' => '150',
 348                                 'width' => '300',
 349                         ),
 350                         'command' => array( 'type' => 'command' ),
 351                         'form' => array(
 352                                 'action' => 'GET',
 353                                 'autocomplete' => 'on',
 354                                 'enctype' => 'application/x-www-form-urlencoded',
 355                         ),
 356                         'input' => array(
 357                                 'formaction' => 'GET',
 358                                 'type' => 'text',
 359                         ),
 360                         'keygen' => array( 'keytype' => 'rsa' ),
 361                         'link' => array( 'media' => 'all' ),
 362                         'menu' => array( 'type' => 'list' ),
 363                         // Note: the use of text/javascript here instead of other JavaScript
 364                         // MIME types follows the HTML5 spec.
 365                         'script' => array( 'type' => 'text/javascript' ),
 366                         'style' => array(
 367                                 'media' => 'all',
 368                                 'type' => 'text/css',
 369                         ),
 370                         'textarea' => array( 'wrap' => 'soft' ),
 371                 );
 372
 373                 $element = strtolower( $element );
 374
 375                 foreach ( $attribs as $attrib => $value ) {
 376                         $lcattrib = strtolower( $attrib );
 377                         if ( is_array( $value ) ) {
 378                                 $value = implode( ' ', $value );
 379                         } else {
 380                                 $value = strval( $value );
 381                         }
 382
 383                         // Simple checks using $attribDefaults
 384                         if ( isset( $attribDefaults[$element][$lcattrib] )
 385                                 && $attribDefaults[$element][$lcattrib] == $value
 386                         ) {
 387                                 unset( $attribs[$attrib] );
 388                         }
 389
 390                         if ( $lcattrib == 'class' && $value == '' ) {
 391                                 unset( $attribs[$attrib] );
 392                         }
 393                 }
 394
 395                 // More subtle checks
 396                 if ( $element === 'link'
 397                         && isset( $attribs['type'] ) && strval( $attribs['type'] ) == 'text/css'
 398                 ) {
 399                         unset( $attribs['type'] );
 400                 }
 401                 if ( $element === 'input' ) {
 402                         $type = isset( $attribs['type'] ) ? $attribs['type'] : null;
 403                         $value = isset( $attribs['value'] ) ? $attribs['value'] : null;
 404                         if ( $type === 'checkbox' || $type === 'radio' ) {
 405                                 // The default value for checkboxes and radio buttons is 'on'
 406                                 // not ''. By stripping value="" we break radio boxes that
 407                                 // actually wants empty values.
 408                                 if ( $value === 'on' ) {
 409                                         unset( $attribs['value'] );
 410                                 }
 411                         } elseif ( $type === 'submit' ) {
 412                                 // The default value for submit appears to be "Submit" but
 413                                 // let's not bother stripping out localized text that matches
 414                                 // that.
 415                         } else {
 416                                 // The default value for nearly every other field type is ''
 417                                 // The 'range' and 'color' types use different defaults but
 418                                 // stripping a value="" does not hurt them.
 419                                 if ( $value === '' ) {
 420                                         unset( $attribs['value'] );
 421                                 }
 422                         }
 423                 }
 424                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 425                         if ( in_array( 'multiple', $attribs )
 426                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 427                         ) {
 428                                 // A multi-select
 429                                 if ( strval( $attribs['size'] ) == '4' ) {
 430                                         unset( $attribs['size'] );
 431                                 }
 432                         } else {
 433                                 // Single select
 434                                 if ( strval( $attribs['size'] ) == '1' ) {
 435                                         unset( $attribs['size'] );
 436                                 }
 437                         }
 438                 }
 439
 440                 return $attribs;
 441         }
 442
 443         /**
 444          * Given an associative array of element attributes, generate a string
 445          * to stick after the element name in HTML output.  Like array( 'href' =>
 446          * 'http://www.mediawiki.org/' ) becomes something like
 447          * ' href="http://www.mediawiki.org"'.  Again, this is like
 448          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 449          * For instance, it will omit quotation marks if $wgWellFormedXml is false,
 450          * and will treat boolean attributes specially.
 451          *
 452          * Attributes that can contain space-separated lists ('class', 'accesskey' and 'rel') array
 453          * values are allowed as well, which will automagically be normalized
 454          * and converted to a space-separated string. In addition to a numerical
 455          * array, the attribute value may also be an associative array. See the
 456          * example below for how that works.
 457          *
 458          * @par Numerical array
 459          * @code
 460          *     Html::element( 'em', array(
 461          *         'class' => array( 'foo', 'bar' )
 462          *     ) );
 463          *     // gives '<em class="foo bar"></em>'
 464          * @endcode
 465          *
 466          * @par Associative array
 467          * @code
 468          *     Html::element( 'em', array(
 469          *         'class' => array( 'foo', 'bar', 'foo' => false, 'quux' => true )
 470          *     ) );
 471          *     // gives '<em class="bar quux"></em>'
 472          * @endcode
 473          *
 474          * @param array $attribs Associative array of attributes, e.g., array(
 475          *   'href' => 'http://www.mediawiki.org/' ).  Values will be HTML-escaped.
 476          *   A value of false means to omit the attribute.  For boolean attributes,
 477          *   you can omit the key, e.g., array( 'checked' ) instead of
 478          *   array( 'checked' => 'checked' ) or such.
 479          *
 480          * @throws MWException If an attribute that doesn't allow lists is set to an array
 481          * @return string HTML fragment that goes between element name and '>'
 482          *   (starting with a space if at least one attribute is output)
 483          */
 484         public static function expandAttributes( array $attribs ) {
 485                 global $wgWellFormedXml;
 486
 487                 $ret = '';
 488                 foreach ( $attribs as $key => $value ) {
 489                         // Support intuitive array( 'checked' => true/false ) form
 490                         if ( $value === false || is_null( $value ) ) {
 491                                 continue;
 492                         }
 493
 494                         // For boolean attributes, support array( 'foo' ) instead of
 495                         // requiring array( 'foo' => 'meaningless' ).
 496                         if ( is_int( $key ) && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 497                                 $key = $value;
 498                         }
 499
 500                         // Not technically required in HTML5 but we'd like consistency
 501                         // and better compression anyway.
 502                         $key = strtolower( $key );
 503
 504                         // Bug 23769: Blacklist all form validation attributes for now.  Current
 505                         // (June 2010) WebKit has no UI, so the form just refuses to submit
 506                         // without telling the user why, which is much worse than failing
 507                         // server-side validation.  Opera is the only other implementation at
 508                         // this time, and has ugly UI, so just kill the feature entirely until
 509                         // we have at least one good implementation.
 510
 511                         // As the default value of "1" for "step" rejects decimal
 512                         // numbers to be entered in 'type="number"' fields, allow
 513                         // the special case 'step="any"'.
 514
 515                         if ( in_array( $key, array( 'max', 'min', 'pattern', 'required' ) )
 516                                 || $key === 'step' && $value !== 'any' ) {
 517                                 continue;
 518                         }
 519
 520                         // http://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 521                         // http://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 522                         $spaceSeparatedListAttributes = array(
 523                                 'class', // html4, html5
 524                                 'accesskey', // as of html5, multiple space-separated values allowed
 525                                 // html4-spec doesn't document rel= as space-separated
 526                                 // but has been used like that and is now documented as such
 527                                 // in the html5-spec.
 528                                 'rel',
 529                         );
 530
 531                         // Specific features for attributes that allow a list of space-separated values
 532                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 533                                 // Apply some normalization and remove duplicates
 534
 535                                 // Convert into correct array. Array can contain space-separated
 536                                 // values. Implode/explode to get those into the main array as well.
 537                                 if ( is_array( $value ) ) {
 538                                         // If input wasn't an array, we can skip this step
 539                                         $newValue = array();
 540                                         foreach ( $value as $k => $v ) {
 541                                                 if ( is_string( $v ) ) {
 542                                                         // String values should be normal `array( 'foo' )`
 543                                                         // Just append them
 544                                                         if ( !isset( $value[$v] ) ) {
 545                                                                 // As a special case don't set 'foo' if a
 546                                                                 // separate 'foo' => true/false exists in the array
 547                                                                 // keys should be authoritative
 548                                                                 $newValue[] = $v;
 549                                                         }
 550                                                 } elseif ( $v ) {
 551                                                         // If the value is truthy but not a string this is likely
 552                                                         // an array( 'foo' => true ), falsy values don't add strings
 553                                                         $newValue[] = $k;
 554                                                 }
 555                                         }
 556                                         $value = implode( ' ', $newValue );
 557                                 }
 558                                 $value = explode( ' ', $value );
 559
 560                                 // Normalize spacing by fixing up cases where people used
 561                                 // more than 1 space and/or a trailing/leading space
 562                                 $value = array_diff( $value, array( '', ' ' ) );
 563
 564                                 // Remove duplicates and create the string
 565                                 $value = implode( ' ', array_unique( $value ) );
 566                         } elseif ( is_array( $value ) ) {
 567                                 throw new MWException( "HTML attribute $key can not contain a list of values" );
 568                         }
 569
 570                         // See the "Attributes" section in the HTML syntax part of HTML5,
 571                         // 9.1.2.3 as of 2009-08-10.  Most attributes can have quotation
 572                         // marks omitted, but not all.  (Although a literal " is not
 573                         // permitted, we don't check for that, since it will be escaped
 574                         // anyway.)
 575
 576                         // See also research done on further characters that need to be
 577                         // escaped: http://code.google.com/p/html5lib/issues/detail?id=93
 578                         $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}"
 579                                 . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}"
 580                                 . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}";
 581                         if ( $wgWellFormedXml || $value === '' || preg_match( "![$badChars]!u", $value ) ) {
 582                                 $quote = '"';
 583                         } else {
 584                                 $quote = '';
 585                         }
 586
 587                         if ( in_array( $key, self::$boolAttribs ) ) {
 588                                 // In HTML5, we can leave the value empty. If we don't need
 589                                 // well-formed XML, we can omit the = entirely.
 590                                 if ( !$wgWellFormedXml ) {
 591                                         $ret .= " $key";
 592                                 } else {
 593                                         $ret .= " $key=\"\"";
 594                                 }
 595                         } else {
 596                                 // Apparently we need to entity-encode \n, \r, \t, although the
 597                                 // spec doesn't mention that.  Since we're doing strtr() anyway,
 598                                 // we may as well not call htmlspecialchars().
 599                                 // @todo FIXME: Verify that we actually need to
 600                                 // escape \n\r\t here, and explain why, exactly.
 601                                 #
 602                                 // We could call Sanitizer::encodeAttribute() for this, but we
 603                                 // don't because we're stubborn and like our marginal savings on
 604                                 // byte size from not having to encode unnecessary quotes.
 605                                 // The only difference between this transform and the one by
 606                                 // Sanitizer::encodeAttribute() is '<' is only encoded here if
 607                                 // $wgWellFormedXml is set, and ' is not encoded.
 608                                 $map = array(
 609                                         '&' => '&amp;',
 610                                         '"' => '&quot;',
 611                                         '>' => '&gt;',
 612                                         "\n" => '&#10;',
 613                                         "\r" => '&#13;',
 614                                         "\t" => '&#9;'
 615                                 );
 616                                 if ( $wgWellFormedXml ) {
 617                                         // This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue>
 618                                         // But reportedly it breaks some XML tools?
 619                                         // @todo FIXME: Is this really true?
 620                                         $map['<'] = '&lt;';
 621                                 }
 622                                 $ret .= " $key=$quote" . strtr( $value, $map ) . $quote;
 623                         }
 624                 }
 625                 return $ret;
 626         }
 627
 628         /**
 629          * Output a "<script>" tag with the given contents.
 630          *
 631          * @todo do some useful escaping as well, like if $contents contains
 632          * literal "</script>" or (for XML) literal "]]>".
 633          *
 634          * @param string $contents JavaScript
 635          * @return string Raw HTML
 636          */
 637         public static function inlineScript( $contents ) {
 638                 global $wgWellFormedXml;
 639
 640                 $attrs = array();
 641
 642                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 643                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 644                 }
 645
 646                 return self::rawElement( 'script', $attrs, $contents );
 647         }
 648
 649         /**
 650          * Output a "<script>" tag linking to the given URL, e.g.,
 651          * "<script src=foo.js></script>".
 652          *
 653          * @param string $url
 654          * @return string Raw HTML
 655          */
 656         public static function linkedScript( $url ) {
 657                 $attrs = array( 'src' => $url );
 658
 659                 return self::element( 'script', $attrs );
 660         }
 661
 662         /**
 663          * Output a "<style>" tag with the given contents for the given media type
 664          * (if any).  TODO: do some useful escaping as well, like if $contents
 665          * contains literal "</style>" (admittedly unlikely).
 666          *
 667          * @param string $contents CSS
 668          * @param string $media A media type string, like 'screen'
 669          * @return string Raw HTML
 670          */
 671         public static function inlineStyle( $contents, $media = 'all' ) {
 672                 global $wgWellFormedXml;
 673
 674                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 675                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 676                 }
 677
 678                 return self::rawElement( 'style', array(
 679                         'type' => 'text/css',
 680                         'media' => $media,
 681                 ), $contents );
 682         }
 683
 684         /**
 685          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 686          * media type (if any).
 687          *
 688          * @param string $url
 689          * @param string $media A media type string, like 'screen'
 690          * @return string Raw HTML
 691          */
 692         public static function linkedStyle( $url, $media = 'all' ) {
 693                 return self::element( 'link', array(
 694                         'rel' => 'stylesheet',
 695                         'href' => $url,
 696                         'type' => 'text/css',
 697                         'media' => $media,
 698                 ) );
 699         }
 700
 701         /**
 702          * Convenience function to produce an "<input>" element.  This supports the
 703          * new HTML5 input types and attributes.
 704          *
 705          * @param string $name Name attribute
 706          * @param string $value Value attribute
 707          * @param string $type Type attribute
 708          * @param array $attribs Associative array of miscellaneous extra
 709          *   attributes, passed to Html::element()
 710          * @return string Raw HTML
 711          */
 712         public static function input( $name, $value = '', $type = 'text', array $attribs = array() ) {
 713                 $attribs['type'] = $type;
 714                 $attribs['value'] = $value;
 715                 $attribs['name'] = $name;
 716                 if ( in_array( $type, array( 'text', 'search', 'email', 'password', 'number' ) ) ) {
 717                         $attribs = self::getTextInputAttributes( $attribs );
 718                 }
 719                 return self::element( 'input', $attribs );
 720         }
 721
 722         /**
 723          * Convenience function to produce a checkbox (input element with type=checkbox)
 724          *
 725          * @param string $name Name attribute
 726          * @param bool $checked Whether the checkbox is checked or not
 727          * @param array $attribs Array of additional attributes
 728          * @return string Raw HTML
 729          */
 730         public static function check( $name, $checked = false, array $attribs = array() ) {
 731                 if ( isset( $attribs['value'] ) ) {
 732                         $value = $attribs['value'];
 733                         unset( $attribs['value'] );
 734                 } else {
 735                         $value = 1;
 736                 }
 737
 738                 if ( $checked ) {
 739                         $attribs[] = 'checked';
 740                 }
 741
 742                 return self::input( $name, $value, 'checkbox', $attribs );
 743         }
 744
 745         /**
 746          * Convenience function to produce a checkbox (input element with type=checkbox)
 747          *
 748          * @param string $name Name attribute
 749          * @param bool $checked Whether the checkbox is checked or not
 750          * @param array $attribs Array of additional attributes
 751          * @return string Raw HTML
 752          */
 753         public static function radio( $name, $checked = false, array $attribs = array() ) {
 754                 if ( isset( $attribs['value'] ) ) {
 755                         $value = $attribs['value'];
 756                         unset( $attribs['value'] );
 757                 } else {
 758                         $value = 1;
 759                 }
 760
 761                 if ( $checked ) {
 762                         $attribs[] = 'checked';
 763                 }
 764
 765                 return self::input( $name, $value, 'radio', $attribs );
 766         }
 767
 768         /**
 769          * Convenience function for generating a label for inputs.
 770          *
 771          * @param string $label Contents of the label
 772          * @param string $id ID of the element being labeled
 773          * @param array $attribs Additional attributes
 774          * @return string Raw HTML
 775          */
 776         public static function label( $label, $id, array $attribs = array() ) {
 777                 $attribs += array(
 778                         'for' => $id
 779                 );
 780                 return self::element( 'label', $attribs, $label );
 781         }
 782
 783         /**
 784          * Convenience function to produce an input element with type=hidden
 785          *
 786          * @param string $name Name attribute
 787          * @param string $value Value attribute
 788          * @param array $attribs Associative array of miscellaneous extra
 789          *   attributes, passed to Html::element()
 790          * @return string Raw HTML
 791          */
 792         public static function hidden( $name, $value, array $attribs = array() ) {
 793                 return self::input( $name, $value, 'hidden', $attribs );
 794         }
 795
 796         /**
 797          * Convenience function to produce a <textarea> element.
 798          *
 799          * This supports leaving out the cols= and rows= which Xml requires and are
 800          * required by HTML4/XHTML but not required by HTML5.
 801          *
 802          * @param string $name Name attribute
 803          * @param string $value Value attribute
 804          * @param array $attribs Associative array of miscellaneous extra
 805          *   attributes, passed to Html::element()
 806          * @return string Raw HTML
 807          */
 808         public static function textarea( $name, $value = '', array $attribs = array() ) {
 809                 $attribs['name'] = $name;
 810
 811                 if ( substr( $value, 0, 1 ) == "\n" ) {
 812                         // Workaround for bug 12130: browsers eat the initial newline
 813                         // assuming that it's just for show, but they do keep the later
 814                         // newlines, which we may want to preserve during editing.
 815                         // Prepending a single newline
 816                         $spacedValue = "\n" . $value;
 817                 } else {
 818                         $spacedValue = $value;
 819                 }
 820                 return self::element( 'textarea', self::getTextInputAttributes( $attribs ), $spacedValue );
 821         }
 822
 823         /**
 824          * Build a drop-down box for selecting a namespace
 825          *
 826          * @param array $params Params to set.
 827          * - selected: [optional] Id of namespace which should be pre-selected
 828          * - all: [optional] Value of item for "all namespaces". If null or unset,
 829          *   no "<option>" is generated to select all namespaces.
 830          * - label: text for label to add before the field.
 831          * - exclude: [optional] Array of namespace ids to exclude.
 832          * - disable: [optional] Array of namespace ids for which the option should
 833          *   be disabled in the selector.
 834          * @param array $selectAttribs HTML attributes for the generated select element.
 835          * - id:   [optional], default: 'namespace'.
 836          * - name: [optional], default: 'namespace'.
 837          * @return string HTML code to select a namespace.
 838          */
 839         public static function namespaceSelector( array $params = array(),
 840                 array $selectAttribs = array()
 841         ) {
 842                 global $wgContLang;
 843
 844                 ksort( $selectAttribs );
 845
 846                 // Is a namespace selected?
 847                 if ( isset( $params['selected'] ) ) {
 848                         // If string only contains digits, convert to clean int. Selected could also
 849                         // be "all" or "" etc. which needs to be left untouched.
 850                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 851                         // and returns false for already clean ints. Use regex instead..
 852                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 853                                 $params['selected'] = intval( $params['selected'] );
 854                         }
 855                         // else: leaves it untouched for later processing
 856                 } else {
 857                         $params['selected'] = '';
 858                 }
 859
 860                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 861                         $params['exclude'] = array();
 862                 }
 863                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 864                         $params['disable'] = array();
 865                 }
 866
 867                 // Associative array between option-values and option-labels
 868                 $options = array();
 869
 870                 if ( isset( $params['all'] ) ) {
 871                         // add an option that would let the user select all namespaces.
 872                         // Value is provided by user, the name shown is localized for the user.
 873                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 874                 }
 875                 // Add all namespaces as options (in the content language)
 876                 $options += $wgContLang->getFormattedNamespaces();
 877
 878                 // Convert $options to HTML and filter out namespaces below 0
 879                 $optionsHtml = array();
 880                 foreach ( $options as $nsId => $nsName ) {
 881                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 882                                 continue;
 883                         }
 884                         if ( $nsId === NS_MAIN ) {
 885                                 // For other namespaces use the namespace prefix as label, but for
 886                                 // main we don't use "" but the user message describing it (e.g. "(Main)" or "(Article)")
 887                                 $nsName = wfMessage( 'blanknamespace' )->text();
 888                         } elseif ( is_int( $nsId ) ) {
 889                                 $nsName = $wgContLang->convertNamespace( $nsId );
 890                         }
 891                         $optionsHtml[] = self::element(
 892                                 'option', array(
 893                                         'disabled' => in_array( $nsId, $params['disable'] ),
 894                                         'value' => $nsId,
 895                                         'selected' => $nsId === $params['selected'],
 896                                 ), $nsName
 897                         );
 898                 }
 899
 900                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 901                         $selectAttribs['id'] = 'namespace';
 902                 }
 903
 904                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 905                         $selectAttribs['name'] = 'namespace';
 906                 }
 907
 908                 $ret = '';
 909                 if ( isset( $params['label'] ) ) {
 910                         $ret .= self::element(
 911                                 'label', array(
 912                                         'for' => isset( $selectAttribs['id'] ) ? $selectAttribs['id'] : null,
 913                                 ), $params['label']
 914                         ) . '&#160;';
 915                 }
 916
 917                 // Wrap options in a <select>
 918                 $ret .= self::openElement( 'select', $selectAttribs )
 919                         . "\n"
 920                         . implode( "\n", $optionsHtml )
 921                         . "\n"
 922                         . self::closeElement( 'select' );
 923
 924                 return $ret;
 925         }
 926
 927         /**
 928          * Constructs the opening html-tag with necessary doctypes depending on
 929          * global variables.
 930          *
 931          * @param array $attribs Associative array of miscellaneous extra
 932          *   attributes, passed to Html::element() of html tag.
 933          * @return string Raw HTML
 934          */
 935         public static function htmlHeader( array $attribs = array() ) {
 936                 $ret = '';
 937
 938                 global $wgHtml5Version, $wgMimeType, $wgXhtmlNamespaces;
 939
 940                 $isXHTML = self::isXmlMimeType( $wgMimeType );
 941
 942                 if ( $isXHTML ) { // XHTML5
 943                         // XML MIME-typed markup should have an xml header.
 944                         // However a DOCTYPE is not needed.
 945                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 946
 947                         // Add the standard xmlns
 948                         $attribs['xmlns'] = 'http://www.w3.org/1999/xhtml';
 949
 950                         // And support custom namespaces
 951                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 952                                 $attribs["xmlns:$tag"] = $ns;
 953                         }
 954                 } else { // HTML5
 955                         // DOCTYPE
 956                         $ret .= "<!DOCTYPE html>\n";
 957                 }
 958
 959                 if ( $wgHtml5Version ) {
 960                         $attribs['version'] = $wgHtml5Version;
 961                 }
 962
 963                 $html = self::openElement( 'html', $attribs );
 964
 965                 if ( $html ) {
 966                         $html .= "\n";
 967                 }
 968
 969                 $ret .= $html;
 970
 971                 return $ret;
 972         }
 973
 974         /**
 975          * Determines if the given MIME type is xml.
 976          *
 977          * @param string $mimetype MIME type
 978          * @return bool
 979          */
 980         public static function isXmlMimeType( $mimetype ) {
 981                 # http://www.whatwg.org/html/infrastructure.html#xml-mime-type
 982                 # * text/xml
 983                 # * application/xml
 984                 # * Any MIME type with a subtype ending in +xml (this implicitly includes application/xhtml+xml)
 985                 return (bool)preg_match( '!^(text|application)/xml$|^.+/.+\+xml$!', $mimetype );
 986         }
 987
 988         /**
 989          * Get HTML for an info box with an icon.
 990          *
 991          * @param string $text Wikitext, get this with wfMessage()->plain()
 992          * @param string $icon Path to icon file (used as 'src' attribute)
 993          * @param string $alt Alternate text for the icon
 994          * @param string $class Additional class name to add to the wrapper div
 995          *
 996          * @return string
 997          */
 998         static function infoBox( $text, $icon, $alt, $class = '' ) {
 999                 $s = self::openElement( 'div', array( 'class' => "mw-infobox $class" ) );
1000
1001                 $s .= self::openElement( 'div', array( 'class' => 'mw-infobox-left' ) ) .
1002                                 self::element( 'img',
1003                                         array(
1004                                                 'src' => $icon,
1005                                                 'alt' => $alt,
1006                                         )
1007                                 ) .
1008                                 self::closeElement( 'div' );
1009
1010                 $s .= self::openElement( 'div', array( 'class' => 'mw-infobox-right' ) ) .
1011                                 $text .
1012                                 self::closeElement( 'div' );
1013                 $s .= self::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
1014
1015                 $s .= self::closeElement( 'div' );
1016
1017                 $s .= self::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
1018
1019                 return $s;
1020         }
1021
1022         /**
1023          * Generate a srcset attribute value.
1024          *
1025          * Generates a srcset attribute value from an array mapping pixel densities
1026          * to URLs. A trailing 'x' in pixel density values is optional.
1027          *
1028          * @note srcset width and height values are not supported.
1029          *
1030          * @see http://www.whatwg.org/html/embedded-content-1.html#attr-img-srcset
1031          *
1032          * @par Example:
1033          * @code
1034          *     Html::srcSet( array(
1035          *         '1x'   => 'standard.jpeg',
1036          *         '1.5x' => 'large.jpeg',
1037          *         '3x'   => 'extra-large.jpeg',
1038          *     ) );
1039          *     // gives 'standard.jpeg 1x, large.jpeg 1.5x, extra-large.jpeg 2x'
1040          * @endcode
1041          *
1042          * @param string[] $urls
1043          * @return string
1044          */
1045         static function srcSet( array $urls ) {
1046                 $candidates = array();
1047                 foreach ( $urls as $density => $url ) {
1048                         // Cast density to float to strip 'x'.
1049                         $candidates[] = $url . ' ' . (float)$density . 'x';
1050                 }
1051                 return implode( ", ", $candidates );
1052         }
1053 }