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          * Returns an HTML element in a string.  The major advantage here over
 106          * manually typing out the HTML is that it will escape all attribute
 107          * values.  If you're hardcoding all the attributes, or there are none, you
 108          * should probably just type out the html element yourself.
 109          *
 110          * This is quite similar to Xml::tags(), but it implements some useful
 111          * HTML-specific logic.  For instance, there is no $allowShortTag
 112          * parameter: the closing tag is magically omitted if $element has an empty
 113          * content model.  If $wgWellFormedXml is false, then a few bytes will be
 114          * shaved off the HTML output as well.
 115          *
 116          * @param string $element The element's name, e.g., 'a'
 117          * @param array $attribs Associative array of attributes, e.g., array(
 118          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 119          *   further documentation.
 120          * @param string $contents The raw HTML contents of the element: *not*
 121          *   escaped!
 122          * @return string Raw HTML
 123          */
 124         public static function rawElement( $element, $attribs = array(), $contents = '' ) {
 125                 global $wgWellFormedXml;
 126                 $start = self::openElement( $element, $attribs );
 127                 if ( in_array( $element, self::$voidElements ) ) {
 128                         if ( $wgWellFormedXml ) {
 129                                 // Silly XML.
 130                                 return substr( $start, 0, -1 ) . ' />';
 131                         }
 132                         return $start;
 133                 } else {
 134                         return "$start$contents" . self::closeElement( $element );
 135                 }
 136         }
 137
 138         /**
 139          * Identical to rawElement(), but HTML-escapes $contents (like
 140          * Xml::element()).
 141          *
 142          * @param string $element
 143          * @param array $attribs
 144          * @param string $contents
 145          *
 146          * @return string
 147          */
 148         public static function element( $element, $attribs = array(), $contents = '' ) {
 149                 return self::rawElement( $element, $attribs, strtr( $contents, array(
 150                         // There's no point in escaping quotes, >, etc. in the contents of
 151                         // elements.
 152                         '&' => '&amp;',
 153                         '<' => '&lt;'
 154                 ) ) );
 155         }
 156
 157         /**
 158          * Identical to rawElement(), but has no third parameter and omits the end
 159          * tag (and the self-closing '/' in XML mode for empty elements).
 160          *
 161          * @param string $element
 162          * @param array $attribs
 163          *
 164          * @return string
 165          */
 166         public static function openElement( $element, $attribs = array() ) {
 167                 global $wgWellFormedXml;
 168                 $attribs = (array)$attribs;
 169                 // This is not required in HTML5, but let's do it anyway, for
 170                 // consistency and better compression.
 171                 $element = strtolower( $element );
 172
 173                 // In text/html, initial <html> and <head> tags can be omitted under
 174                 // pretty much any sane circumstances, if they have no attributes.  See:
 175                 // <http://www.whatwg.org/html/syntax.html#optional-tags>
 176                 if ( !$wgWellFormedXml && !$attribs
 177                 && in_array( $element, array( 'html', 'head' ) ) ) {
 178                         return '';
 179                 }
 180
 181                 // Remove invalid input types
 182                 if ( $element == 'input' ) {
 183                         $validTypes = array(
 184                                 'hidden',
 185                                 'text',
 186                                 'password',
 187                                 'checkbox',
 188                                 'radio',
 189                                 'file',
 190                                 'submit',
 191                                 'image',
 192                                 'reset',
 193                                 'button',
 194
 195                                 // HTML input types
 196                                 'datetime',
 197                                 'datetime-local',
 198                                 'date',
 199                                 'month',
 200                                 'time',
 201                                 'week',
 202                                 'number',
 203                                 'range',
 204                                 'email',
 205                                 'url',
 206                                 'search',
 207                                 'tel',
 208                                 'color',
 209                         );
 210                         if ( isset( $attribs['type'] )
 211                         && !in_array( $attribs['type'], $validTypes ) ) {
 212                                 unset( $attribs['type'] );
 213                         }
 214                 }
 215
 216                 // According to standard the default type for <button> elements is "submit".
 217                 // Depending on compatibility mode IE might use "button", instead.
 218                 // We enforce the standard "submit".
 219                 if ( $element == 'button' && !isset( $attribs['type'] ) ) {
 220                         $attribs['type'] = 'submit';
 221                 }
 222
 223                 return "<$element" . self::expandAttributes(
 224                         self::dropDefaults( $element, $attribs ) ) . '>';
 225         }
 226
 227         /**
 228          * Returns "</$element>"
 229          *
 230          * @since 1.17
 231          * @param string $element Name of the element, e.g., 'a'
 232          * @return string A closing tag
 233          */
 234         public static function closeElement( $element ) {
 235                 $element = strtolower( $element );
 236
 237                 return "</$element>";
 238         }
 239
 240         /**
 241          * Given an element name and an associative array of element attributes,
 242          * return an array that is functionally identical to the input array, but
 243          * possibly smaller.  In particular, attributes might be stripped if they
 244          * are given their default values.
 245          *
 246          * This method is not guaranteed to remove all redundant attributes, only
 247          * some common ones and some others selected arbitrarily at random.  It
 248          * only guarantees that the output array should be functionally identical
 249          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 250          *
 251          * @param string $element Name of the element, e.g., 'a'
 252          * @param array $attribs Associative array of attributes, e.g., array(
 253          *   'href' => 'http://www.mediawiki.org/' ).  See expandAttributes() for
 254          *   further documentation.
 255          * @return array An array of attributes functionally identical to $attribs
 256          */
 257         private static function dropDefaults( $element, $attribs ) {
 258
 259                 // Whenever altering this array, please provide a covering test case
 260                 // in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 261                 static $attribDefaults = array(
 262                         'area' => array( 'shape' => 'rect' ),
 263                         'button' => array(
 264                                 'formaction' => 'GET',
 265                                 'formenctype' => 'application/x-www-form-urlencoded',
 266                         ),
 267                         'canvas' => array(
 268                                 'height' => '150',
 269                                 'width' => '300',
 270                         ),
 271                         'command' => array( 'type' => 'command' ),
 272                         'form' => array(
 273                                 'action' => 'GET',
 274                                 'autocomplete' => 'on',
 275                                 'enctype' => 'application/x-www-form-urlencoded',
 276                         ),
 277                         'input' => array(
 278                                 'formaction' => 'GET',
 279                                 'type' => 'text',
 280                         ),
 281                         'keygen' => array( 'keytype' => 'rsa' ),
 282                         'link' => array( 'media' => 'all' ),
 283                         'menu' => array( 'type' => 'list' ),
 284                         // Note: the use of text/javascript here instead of other JavaScript
 285                         // MIME types follows the HTML5 spec.
 286                         'script' => array( 'type' => 'text/javascript' ),
 287                         'style' => array(
 288                                 'media' => 'all',
 289                                 'type' => 'text/css',
 290                         ),
 291                         'textarea' => array( 'wrap' => 'soft' ),
 292                 );
 293
 294                 $element = strtolower( $element );
 295
 296                 foreach ( $attribs as $attrib => $value ) {
 297                         $lcattrib = strtolower( $attrib );
 298                         if ( is_array( $value ) ) {
 299                                 $value = implode( ' ', $value );
 300                         } else {
 301                                 $value = strval( $value );
 302                         }
 303
 304                         // Simple checks using $attribDefaults
 305                         if ( isset( $attribDefaults[$element][$lcattrib] ) &&
 306                         $attribDefaults[$element][$lcattrib] == $value ) {
 307                                 unset( $attribs[$attrib] );
 308                         }
 309
 310                         if ( $lcattrib == 'class' && $value == '' ) {
 311                                 unset( $attribs[$attrib] );
 312                         }
 313                 }
 314
 315                 // More subtle checks
 316                 if ( $element === 'link' && isset( $attribs['type'] )
 317                 && strval( $attribs['type'] ) == 'text/css' ) {
 318                         unset( $attribs['type'] );
 319                 }
 320                 if ( $element === 'input' ) {
 321                         $type = isset( $attribs['type'] ) ? $attribs['type'] : null;
 322                         $value = isset( $attribs['value'] ) ? $attribs['value'] : null;
 323                         if ( $type === 'checkbox' || $type === 'radio' ) {
 324                                 // The default value for checkboxes and radio buttons is 'on'
 325                                 // not ''. By stripping value="" we break radio boxes that
 326                                 // actually wants empty values.
 327                                 if ( $value === 'on' ) {
 328                                         unset( $attribs['value'] );
 329                                 }
 330                         } elseif ( $type === 'submit' ) {
 331                                 // The default value for submit appears to be "Submit" but
 332                                 // let's not bother stripping out localized text that matches
 333                                 // that.
 334                         } else {
 335                                 // The default value for nearly every other field type is ''
 336                                 // The 'range' and 'color' types use different defaults but
 337                                 // stripping a value="" does not hurt them.
 338                                 if ( $value === '' ) {
 339                                         unset( $attribs['value'] );
 340                                 }
 341                         }
 342                 }
 343                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 344                         if ( in_array( 'multiple', $attribs )
 345                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 346                         ) {
 347                                 // A multi-select
 348                                 if ( strval( $attribs['size'] ) == '4' ) {
 349                                         unset( $attribs['size'] );
 350                                 }
 351                         } else {
 352                                 // Single select
 353                                 if ( strval( $attribs['size'] ) == '1' ) {
 354                                         unset( $attribs['size'] );
 355                                 }
 356                         }
 357                 }
 358
 359                 return $attribs;
 360         }
 361
 362         /**
 363          * Given an associative array of element attributes, generate a string
 364          * to stick after the element name in HTML output.  Like array( 'href' =>
 365          * 'http://www.mediawiki.org/' ) becomes something like
 366          * ' href="http://www.mediawiki.org"'.  Again, this is like
 367          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 368          * For instance, it will omit quotation marks if $wgWellFormedXml is false,
 369          * and will treat boolean attributes specially.
 370          *
 371          * Attributes that can contain space-separated lists ('class', 'accesskey' and 'rel') array
 372          * values are allowed as well, which will automagically be normalized
 373          * and converted to a space-separated string. In addition to a numerical
 374          * array, the attribute value may also be an associative array. See the
 375          * example below for how that works.
 376          *
 377          * @par Numerical array
 378          * @code
 379          *     Html::element( 'em', array(
 380          *         'class' => array( 'foo', 'bar' )
 381          *     ) );
 382          *     // gives '<em class="foo bar"></em>'
 383          * @endcode
 384          *
 385          * @par Associative array
 386          * @code
 387          *     Html::element( 'em', array(
 388          *         'class' => array( 'foo', 'bar', 'foo' => false, 'quux' => true )
 389          *     ) );
 390          *     // gives '<em class="bar quux"></em>'
 391          * @endcode
 392          *
 393          * @param array $attribs Associative array of attributes, e.g., array(
 394          *   'href' => 'http://www.mediawiki.org/' ).  Values will be HTML-escaped.
 395          *   A value of false means to omit the attribute.  For boolean attributes,
 396          *   you can omit the key, e.g., array( 'checked' ) instead of
 397          *   array( 'checked' => 'checked' ) or such.
 398          *
 399          * @throws MWException If an attribute that doesn't allow lists is set to an array
 400          * @return string HTML fragment that goes between element name and '>'
 401          *   (starting with a space if at least one attribute is output)
 402          */
 403         public static function expandAttributes( $attribs ) {
 404                 global $wgWellFormedXml;
 405
 406                 $ret = '';
 407                 $attribs = (array)$attribs;
 408                 foreach ( $attribs as $key => $value ) {
 409                         // Support intuitive array( 'checked' => true/false ) form
 410                         if ( $value === false || is_null( $value ) ) {
 411                                 continue;
 412                         }
 413
 414                         // For boolean attributes, support array( 'foo' ) instead of
 415                         // requiring array( 'foo' => 'meaningless' ).
 416                         if ( is_int( $key )
 417                         && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 418                                 $key = $value;
 419                         }
 420
 421                         // Not technically required in HTML5 but we'd like consistency
 422                         // and better compression anyway.
 423                         $key = strtolower( $key );
 424
 425                         // Bug 23769: Blacklist all form validation attributes for now.  Current
 426                         // (June 2010) WebKit has no UI, so the form just refuses to submit
 427                         // without telling the user why, which is much worse than failing
 428                         // server-side validation.  Opera is the only other implementation at
 429                         // this time, and has ugly UI, so just kill the feature entirely until
 430                         // we have at least one good implementation.
 431
 432                         // As the default value of "1" for "step" rejects decimal
 433                         // numbers to be entered in 'type="number"' fields, allow
 434                         // the special case 'step="any"'.
 435
 436                         if ( in_array( $key, array( 'max', 'min', 'pattern', 'required' ) )
 437                                 || $key === 'step' && $value !== 'any' ) {
 438                                 continue;
 439                         }
 440
 441                         // http://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 442                         // http://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 443                         $spaceSeparatedListAttributes = array(
 444                                 'class', // html4, html5
 445                                 'accesskey', // as of html5, multiple space-separated values allowed
 446                                 // html4-spec doesn't document rel= as space-separated
 447                                 // but has been used like that and is now documented as such
 448                                 // in the html5-spec.
 449                                 'rel',
 450                         );
 451
 452                         // Specific features for attributes that allow a list of space-separated values
 453                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 454                                 // Apply some normalization and remove duplicates
 455
 456                                 // Convert into correct array. Array can contain space-separated
 457                                 // values. Implode/explode to get those into the main array as well.
 458                                 if ( is_array( $value ) ) {
 459                                         // If input wasn't an array, we can skip this step
 460                                         $newValue = array();
 461                                         foreach ( $value as $k => $v ) {
 462                                                 if ( is_string( $v ) ) {
 463                                                         // String values should be normal `array( 'foo' )`
 464                                                         // Just append them
 465                                                         if ( !isset( $value[$v] ) ) {
 466                                                                 // As a special case don't set 'foo' if a
 467                                                                 // separate 'foo' => true/false exists in the array
 468                                                                 // keys should be authoritative
 469                                                                 $newValue[] = $v;
 470                                                         }
 471                                                 } elseif ( $v ) {
 472                                                         // If the value is truthy but not a string this is likely
 473                                                         // an array( 'foo' => true ), falsy values don't add strings
 474                                                         $newValue[] = $k;
 475                                                 }
 476                                         }
 477                                         $value = implode( ' ', $newValue );
 478                                 }
 479                                 $value = explode( ' ', $value );
 480
 481                                 // Normalize spacing by fixing up cases where people used
 482                                 // more than 1 space and/or a trailing/leading space
 483                                 $value = array_diff( $value, array( '', ' ' ) );
 484
 485                                 // Remove duplicates and create the string
 486                                 $value = implode( ' ', array_unique( $value ) );
 487                         } elseif ( is_array( $value ) ) {
 488                                 throw new MWException( "HTML attribute $key can not contain a list of values" );
 489                         }
 490
 491                         // See the "Attributes" section in the HTML syntax part of HTML5,
 492                         // 9.1.2.3 as of 2009-08-10.  Most attributes can have quotation
 493                         // marks omitted, but not all.  (Although a literal " is not
 494                         // permitted, we don't check for that, since it will be escaped
 495                         // anyway.)
 496                         #
 497                         // See also research done on further characters that need to be
 498                         // escaped: http://code.google.com/p/html5lib/issues/detail?id=93
 499                         $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}"
 500                                 . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}"
 501                                 . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}";
 502                         if ( $wgWellFormedXml || $value === ''
 503                         || preg_match( "![$badChars]!u", $value ) ) {
 504                                 $quote = '"';
 505                         } else {
 506                                 $quote = '';
 507                         }
 508
 509                         if ( in_array( $key, self::$boolAttribs ) ) {
 510                                 // In HTML5, we can leave the value empty. If we don't need
 511                                 // well-formed XML, we can omit the = entirely.
 512                                 if ( !$wgWellFormedXml ) {
 513                                         $ret .= " $key";
 514                                 } else {
 515                                         $ret .= " $key=\"\"";
 516                                 }
 517                         } else {
 518                                 // Apparently we need to entity-encode \n, \r, \t, although the
 519                                 // spec doesn't mention that.  Since we're doing strtr() anyway,
 520                                 // and we don't need <> escaped here, we may as well not call
 521                                 // htmlspecialchars().
 522                                 // @todo FIXME: Verify that we actually need to
 523                                 // escape \n\r\t here, and explain why, exactly.
 524                                 #
 525                                 // We could call Sanitizer::encodeAttribute() for this, but we
 526                                 // don't because we're stubborn and like our marginal savings on
 527                                 // byte size from not having to encode unnecessary quotes.
 528                                 $map = array(
 529                                         '&' => '&amp;',
 530                                         '"' => '&quot;',
 531                                         "\n" => '&#10;',
 532                                         "\r" => '&#13;',
 533                                         "\t" => '&#9;'
 534                                 );
 535                                 if ( $wgWellFormedXml ) {
 536                                         // This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue>
 537                                         // But reportedly it breaks some XML tools?
 538                                         // @todo FIXME: Is this really true?
 539                                         $map['<'] = '&lt;';
 540                                 }
 541                                 $ret .= " $key=$quote" . strtr( $value, $map ) . $quote;
 542                         }
 543                 }
 544                 return $ret;
 545         }
 546
 547         /**
 548          * Output a "<script>" tag with the given contents.
 549          *
 550          * @todo do some useful escaping as well, like if $contents contains
 551          * literal "</script>" or (for XML) literal "]]>".
 552          *
 553          * @param string $contents JavaScript
 554          * @return string Raw HTML
 555          */
 556         public static function inlineScript( $contents ) {
 557                 global $wgWellFormedXml;
 558
 559                 $attrs = array();
 560
 561                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 562                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 563                 }
 564
 565                 return self::rawElement( 'script', $attrs, $contents );
 566         }
 567
 568         /**
 569          * Output a "<script>" tag linking to the given URL, e.g.,
 570          * "<script src=foo.js></script>".
 571          *
 572          * @param string $url
 573          * @return string Raw HTML
 574          */
 575         public static function linkedScript( $url ) {
 576                 $attrs = array( 'src' => $url );
 577
 578                 return self::element( 'script', $attrs );
 579         }
 580
 581         /**
 582          * Output a "<style>" tag with the given contents for the given media type
 583          * (if any).  TODO: do some useful escaping as well, like if $contents
 584          * contains literal "</style>" (admittedly unlikely).
 585          *
 586          * @param string $contents CSS
 587          * @param string $media A media type string, like 'screen'
 588          * @return string Raw HTML
 589          */
 590         public static function inlineStyle( $contents, $media = 'all' ) {
 591                 global $wgWellFormedXml;
 592
 593                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 594                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 595                 }
 596
 597                 return self::rawElement( 'style', array(
 598                         'type' => 'text/css',
 599                         'media' => $media,
 600                 ), $contents );
 601         }
 602
 603         /**
 604          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 605          * media type (if any).
 606          *
 607          * @param string $url
 608          * @param string $media A media type string, like 'screen'
 609          * @return string Raw HTML
 610          */
 611         public static function linkedStyle( $url, $media = 'all' ) {
 612                 return self::element( 'link', array(
 613                         'rel' => 'stylesheet',
 614                         'href' => $url,
 615                         'type' => 'text/css',
 616                         'media' => $media,
 617                 ) );
 618         }
 619
 620         /**
 621          * Convenience function to produce an "<input>" element.  This supports the
 622          * new HTML5 input types and attributes.
 623          *
 624          * @param string $name Name attribute
 625          * @param array $value Value attribute
 626          * @param string $type Type attribute
 627          * @param array $attribs Associative array of miscellaneous extra
 628          *   attributes, passed to Html::element()
 629          * @return string Raw HTML
 630          */
 631         public static function input( $name, $value = '', $type = 'text', $attribs = array() ) {
 632                 $attribs['type'] = $type;
 633                 $attribs['value'] = $value;
 634                 $attribs['name'] = $name;
 635
 636                 return self::element( 'input', $attribs );
 637         }
 638
 639         /**
 640          * Convenience function to produce a checkbox (input element with type=checkbox)
 641          *
 642          * @param string $name Name attribute
 643          * @param bool $checked Whether the checkbox is checked or not
 644          * @param array $attribs Array of additional attributes
 645          */
 646         public static function check( $name, $checked = false, array $attribs = array() ) {
 647                 if ( isset( $attribs['value'] ) ) {
 648                         $value = $attribs['value'];
 649                         unset( $attribs['value'] );
 650                 } else {
 651                         $value = 1;
 652                 }
 653
 654                 if ( $checked ) {
 655                         $attribs[] = 'checked';
 656                 }
 657
 658                 return self::input( $name, $value, 'checkbox', $attribs );
 659         }
 660
 661         /**
 662          * Convenience function to produce a checkbox (input element with type=checkbox)
 663          *
 664          * @param string $name Name attribute
 665          * @param bool $checked Whether the checkbox is checked or not
 666          * @param array $attribs Array of additional attributes
 667          */
 668         public static function radio( $name, $checked = false, array $attribs = array() ) {
 669                 if ( isset( $attribs['value'] ) ) {
 670                         $value = $attribs['value'];
 671                         unset( $attribs['value'] );
 672                 } else {
 673                         $value = 1;
 674                 }
 675
 676                 if ( $checked ) {
 677                         $attribs[] = 'checked';
 678                 }
 679
 680                 return self::input( $name, $value, 'radio', $attribs );
 681         }
 682
 683         /**
 684          * Convenience function for generating a label for inputs.
 685          *
 686          * @param string $label Contents of the label
 687          * @param string $id ID of the element being labeled
 688          * @param array $attribs Additional attributes
 689          */
 690         public static function label( $label, $id, array $attribs = array() ) {
 691                 $attribs += array(
 692                         'for' => $id
 693                 );
 694                 return self::element( 'label', $attribs, $label );
 695         }
 696
 697         /**
 698          * Convenience function to produce an input element with type=hidden
 699          *
 700          * @param string $name Name attribute
 701          * @param string $value Value attribute
 702          * @param array $attribs Associative array of miscellaneous extra
 703          *   attributes, passed to Html::element()
 704          * @return string Raw HTML
 705          */
 706         public static function hidden( $name, $value, $attribs = array() ) {
 707                 return self::input( $name, $value, 'hidden', $attribs );
 708         }
 709
 710         /**
 711          * Convenience function to produce a <textarea> element.
 712          *
 713          * This supports leaving out the cols= and rows= which Xml requires and are
 714          * required by HTML4/XHTML but not required by HTML5.
 715          *
 716          * @param string $name Name attribute
 717          * @param string $value Value attribute
 718          * @param array $attribs Associative array of miscellaneous extra
 719          *   attributes, passed to Html::element()
 720          * @return string Raw HTML
 721          */
 722         public static function textarea( $name, $value = '', $attribs = array() ) {
 723                 $attribs['name'] = $name;
 724
 725                 if ( substr( $value, 0, 1 ) == "\n" ) {
 726                         // Workaround for bug 12130: browsers eat the initial newline
 727                         // assuming that it's just for show, but they do keep the later
 728                         // newlines, which we may want to preserve during editing.
 729                         // Prepending a single newline
 730                         $spacedValue = "\n" . $value;
 731                 } else {
 732                         $spacedValue = $value;
 733                 }
 734                 return self::element( 'textarea', $attribs, $spacedValue );
 735         }
 736
 737         /**
 738          * Build a drop-down box for selecting a namespace
 739          *
 740          * @param array $params Params to set.
 741          * - selected: [optional] Id of namespace which should be pre-selected
 742          * - all: [optional] Value of item for "all namespaces". If null or unset,
 743          *   no "<option>" is generated to select all namespaces.
 744          * - label: text for label to add before the field.
 745          * - exclude: [optional] Array of namespace ids to exclude.
 746          * - disable: [optional] Array of namespace ids for which the option should
 747          *   be disabled in the selector.
 748          * @param array $selectAttribs HTML attributes for the generated select element.
 749          * - id:   [optional], default: 'namespace'.
 750          * - name: [optional], default: 'namespace'.
 751          * @return string HTML code to select a namespace.
 752          */
 753         public static function namespaceSelector( array $params = array(),
 754                 array $selectAttribs = array()
 755         ) {
 756                 global $wgContLang;
 757
 758                 ksort( $selectAttribs );
 759
 760                 // Is a namespace selected?
 761                 if ( isset( $params['selected'] ) ) {
 762                         // If string only contains digits, convert to clean int. Selected could also
 763                         // be "all" or "" etc. which needs to be left untouched.
 764                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 765                         // and returns false for already clean ints. Use regex instead..
 766                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 767                                 $params['selected'] = intval( $params['selected'] );
 768                         }
 769                         // else: leaves it untouched for later processing
 770                 } else {
 771                         $params['selected'] = '';
 772                 }
 773
 774                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 775                         $params['exclude'] = array();
 776                 }
 777                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 778                         $params['disable'] = array();
 779                 }
 780
 781                 // Associative array between option-values and option-labels
 782                 $options = array();
 783
 784                 if ( isset( $params['all'] ) ) {
 785                         // add an option that would let the user select all namespaces.
 786                         // Value is provided by user, the name shown is localized for the user.
 787                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 788                 }
 789                 // Add all namespaces as options (in the content language)
 790                 $options += $wgContLang->getFormattedNamespaces();
 791
 792                 // Convert $options to HTML and filter out namespaces below 0
 793                 $optionsHtml = array();
 794                 foreach ( $options as $nsId => $nsName ) {
 795                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 796                                 continue;
 797                         }
 798                         if ( $nsId === NS_MAIN ) {
 799                                 // For other namespaces use use the namespace prefix as label, but for
 800                                 // main we don't use "" but the user message describing it (e.g. "(Main)" or "(Article)")
 801                                 $nsName = wfMessage( 'blanknamespace' )->text();
 802                         } elseif ( is_int( $nsId ) ) {
 803                                 $nsName = $wgContLang->convertNamespace( $nsId );
 804                         }
 805                         $optionsHtml[] = Html::element(
 806                                 'option', array(
 807                                         'disabled' => in_array( $nsId, $params['disable'] ),
 808                                         'value' => $nsId,
 809                                         'selected' => $nsId === $params['selected'],
 810                                 ), $nsName
 811                         );
 812                 }
 813
 814                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 815                         $selectAttribs['id'] = 'namespace';
 816                 }
 817
 818                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 819                         $selectAttribs['name'] = 'namespace';
 820                 }
 821
 822                 $ret = '';
 823                 if ( isset( $params['label'] ) ) {
 824                         $ret .= Html::element(
 825                                 'label', array(
 826                                         'for' => isset( $selectAttribs['id'] ) ? $selectAttribs['id'] : null,
 827                                 ), $params['label']
 828                         ) . '&#160;';
 829                 }
 830
 831                 // Wrap options in a <select>
 832                 $ret .= Html::openElement( 'select', $selectAttribs )
 833                         . "\n"
 834                         . implode( "\n", $optionsHtml )
 835                         . "\n"
 836                         . Html::closeElement( 'select' );
 837
 838                 return $ret;
 839         }
 840
 841         /**
 842          * Constructs the opening html-tag with necessary doctypes depending on
 843          * global variables.
 844          *
 845          * @param array $attribs Associative array of miscellaneous extra
 846          *   attributes, passed to Html::element() of html tag.
 847          * @return string Raw HTML
 848          */
 849         public static function htmlHeader( $attribs = array() ) {
 850                 $ret = '';
 851
 852                 global $wgHtml5Version, $wgMimeType, $wgXhtmlNamespaces;
 853
 854                 $isXHTML = self::isXmlMimeType( $wgMimeType );
 855
 856                 if ( $isXHTML ) { // XHTML5
 857                         // XML MIME-typed markup should have an xml header.
 858                         // However a DOCTYPE is not needed.
 859                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 860
 861                         // Add the standard xmlns
 862                         $attribs['xmlns'] = 'http://www.w3.org/1999/xhtml';
 863
 864                         // And support custom namespaces
 865                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 866                                 $attribs["xmlns:$tag"] = $ns;
 867                         }
 868                 } else { // HTML5
 869                         // DOCTYPE
 870                         $ret .= "<!DOCTYPE html>\n";
 871                 }
 872
 873                 if ( $wgHtml5Version ) {
 874                         $attribs['version'] = $wgHtml5Version;
 875                 }
 876
 877                 $html = Html::openElement( 'html', $attribs );
 878
 879                 if ( $html ) {
 880                         $html .= "\n";
 881                 }
 882
 883                 $ret .= $html;
 884
 885                 return $ret;
 886         }
 887
 888         /**
 889          * Determines if the given MIME type is xml.
 890          *
 891          * @param string $mimetype MIME type
 892          * @return bool
 893          */
 894         public static function isXmlMimeType( $mimetype ) {
 895                 # http://www.whatwg.org/html/infrastructure.html#xml-mime-type
 896                 # * text/xml
 897                 # * application/xml
 898                 # * Any MIME type with a subtype ending in +xml (this implicitly includes application/xhtml+xml)
 899                 return (bool)preg_match( '!^(text|application)/xml$|^.+/.+\+xml$!', $mimetype );
 900         }
 901
 902         /**
 903          * Get HTML for an info box with an icon.
 904          *
 905          * @param string $text Wikitext, get this with wfMessage()->plain()
 906          * @param string $icon Icon name, file in skins/common/images
 907          * @param string $alt Alternate text for the icon
 908          * @param string $class Additional class name to add to the wrapper div
 909          * @param bool $useStylePath
 910          *
 911          * @return string
 912          */
 913         static function infoBox( $text, $icon, $alt, $class = false, $useStylePath = true ) {
 914                 global $wgStylePath;
 915
 916                 if ( $useStylePath ) {
 917                         $icon = $wgStylePath . '/common/images/' . $icon;
 918                 }
 919
 920                 $s = Html::openElement( 'div', array( 'class' => "mw-infobox $class" ) );
 921
 922                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-left' ) ) .
 923                                 Html::element( 'img',
 924                                         array(
 925                                                 'src' => $icon,
 926                                                 'alt' => $alt,
 927                                         )
 928                                 ) .
 929                                 Html::closeElement( 'div' );
 930
 931                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-right' ) ) .
 932                                 $text .
 933                                 Html::closeElement( 'div' );
 934                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
 935
 936                 $s .= Html::closeElement( 'div' );
 937
 938                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
 939
 940                 return $s;
 941         }
 942
 943         /**
 944          * Generate a srcset attribute value from an array mapping pixel densities
 945          * to URLs. Note that srcset supports width and height values as well, which
 946          * are not used here.
 947          *
 948          * @param array $urls
 949          * @return string
 950          */
 951         static function srcSet( $urls ) {
 952                 $candidates = array();
 953                 foreach ( $urls as $density => $url ) {
 954                         // Image candidate syntax per current whatwg live spec, 2012-09-23:
 955                         // http://www.whatwg.org/html/embedded-content-1.html#attr-img-srcset
 956                         $candidates[] = "{$url} {$density}x";
 957                 }
 958                 return implode( ", ", $candidates );
 959         }
 960 }