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  * $wgHtml5: If this is set to false, then all output should be valid XHTML 1.0
  40  *     Transitional.
  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         private static $HTMLFiveOnlyAttribs = array(
 105                 'autocomplete',
 106                 'autofocus',
 107                 'max',
 108                 'min',
 109                 'multiple',
 110                 'pattern',
 111                 'placeholder',
 112                 'required',
 113                 'step',
 114                 'spellcheck',
 115         );
 116
 117         /**
 118          * Returns an HTML element in a string.  The major advantage here over
 119          * manually typing out the HTML is that it will escape all attribute
 120          * values.  If you're hardcoding all the attributes, or there are none, you
 121          * should probably just type out the html element yourself.
 122          *
 123          * This is quite similar to Xml::tags(), but it implements some useful
 124          * HTML-specific logic.  For instance, there is no $allowShortTag
 125          * parameter: the closing tag is magically omitted if $element has an empty
 126          * content model.  If $wgWellFormedXml is false, then a few bytes will be
 127          * shaved off the HTML output as well.
 128          *
 129          * @param $element string The element's name, e.g., 'a'
 130          * @param $attribs array  Associative array of attributes, e.g., array(
 131          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 132          *   further documentation.
 133          * @param $contents string The raw HTML contents of the element: *not*
 134          *   escaped!
 135          * @return string Raw HTML
 136          */
 137         public static function rawElement( $element, $attribs = array(), $contents = '' ) {
 138                 global $wgWellFormedXml;
 139                 $start = self::openElement( $element, $attribs );
 140                 if ( in_array( $element, self::$voidElements ) ) {
 141                         if ( $wgWellFormedXml ) {
 142                                 # Silly XML.
 143                                 return substr( $start, 0, -1 ) . ' />';
 144                         }
 145                         return $start;
 146                 } else {
 147                         return "$start$contents" . self::closeElement( $element );
 148                 }
 149         }
 150
 151         /**
 152          * Identical to rawElement(), but HTML-escapes $contents (like
 153          * Xml::element()).
 154          *
 155          * @param $element string
 156          * @param $attribs array
 157          * @param $contents string
 158          *
 159          * @return string
 160          */
 161         public static function element( $element, $attribs = array(), $contents = '' ) {
 162                 return self::rawElement( $element, $attribs, strtr( $contents, array(
 163                         # There's no point in escaping quotes, >, etc. in the contents of
 164                         # elements.
 165                         '&' => '&amp;',
 166                         '<' => '&lt;'
 167                 ) ) );
 168         }
 169
 170         /**
 171          * Identical to rawElement(), but has no third parameter and omits the end
 172          * tag (and the self-closing '/' in XML mode for empty elements).
 173          *
 174          * @param $element string
 175          * @param $attribs array
 176          *
 177          * @return string
 178          */
 179         public static function openElement( $element, $attribs = array() ) {
 180                 global $wgHtml5, $wgWellFormedXml;
 181                 $attribs = (array)$attribs;
 182                 # This is not required in HTML5, but let's do it anyway, for
 183                 # consistency and better compression.
 184                 $element = strtolower( $element );
 185
 186                 # In text/html, initial <html> and <head> tags can be omitted under
 187                 # pretty much any sane circumstances, if they have no attributes.  See:
 188                 # <http://www.whatwg.org/specs/web-apps/current-work/multipage/syntax.html#optional-tags>
 189                 if ( !$wgWellFormedXml && !$attribs
 190                 && in_array( $element, array( 'html', 'head' ) ) ) {
 191                         return '';
 192                 }
 193
 194                 # Remove invalid input types
 195                 if ( $element == 'input' ) {
 196                         $validTypes = array(
 197                                 'hidden',
 198                                 'text',
 199                                 'password',
 200                                 'checkbox',
 201                                 'radio',
 202                                 'file',
 203                                 'submit',
 204                                 'image',
 205                                 'reset',
 206                                 'button',
 207                         );
 208
 209                         # Allow more input types in HTML5 mode
 210                         if( $wgHtml5 ) {
 211                                 $validTypes = array_merge( $validTypes, array(
 212                                         'datetime',
 213                                         'datetime-local',
 214                                         'date',
 215                                         'month',
 216                                         'time',
 217                                         'week',
 218                                         'number',
 219                                         'range',
 220                                         'email',
 221                                         'url',
 222                                         'search',
 223                                         'tel',
 224                                         'color',
 225                                 ) );
 226                         }
 227                         if ( isset( $attribs['type'] )
 228                         && !in_array( $attribs['type'], $validTypes ) ) {
 229                                 unset( $attribs['type'] );
 230                         }
 231                 }
 232
 233                 if ( !$wgHtml5 && $element == 'textarea' && isset( $attribs['maxlength'] ) ) {
 234                         unset( $attribs['maxlength'] );
 235                 }
 236
 237                 return "<$element" . self::expandAttributes(
 238                         self::dropDefaults( $element, $attribs ) ) . '>';
 239         }
 240
 241         /**
 242          * Returns "</$element>", except if $wgWellFormedXml is off, in which case
 243          * it returns the empty string when that's guaranteed to be safe.
 244          *
 245          * @since 1.17
 246          * @param $element string Name of the element, e.g., 'a'
 247          * @return string A closing tag, if required
 248          */
 249         public static function closeElement( $element ) {
 250                 global $wgWellFormedXml;
 251
 252                 $element = strtolower( $element );
 253
 254                 # Reference:
 255                 # http://www.whatwg.org/specs/web-apps/current-work/multipage/syntax.html#optional-tags
 256                 if ( !$wgWellFormedXml && in_array( $element, array(
 257                         'html',
 258                         'head',
 259                         'body',
 260                         'li',
 261                         'dt',
 262                         'dd',
 263                         'tr',
 264                         'td',
 265                         'th',
 266                 ) ) ) {
 267                         return '';
 268                 }
 269                 return "</$element>";
 270         }
 271
 272         /**
 273          * Given an element name and an associative array of element attributes,
 274          * return an array that is functionally identical to the input array, but
 275          * possibly smaller.  In particular, attributes might be stripped if they
 276          * are given their default values.
 277          *
 278          * This method is not guaranteed to remove all redundant attributes, only
 279          * some common ones and some others selected arbitrarily at random.  It
 280          * only guarantees that the output array should be functionally identical
 281          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 282          *
 283          * @param $element string Name of the element, e.g., 'a'
 284          * @param $attribs array  Associative array of attributes, e.g., array(
 285          *   'href' => 'http://www.mediawiki.org/' ).  See expandAttributes() for
 286          *   further documentation.
 287          * @return array An array of attributes functionally identical to $attribs
 288          */
 289         private static function dropDefaults( $element, $attribs ) {
 290                 # Don't bother doing anything if we aren't outputting HTML5; it's too
 291                 # much of a pain to maintain two sets of defaults.
 292                 global $wgHtml5;
 293                 if ( !$wgHtml5 ) {
 294                         return $attribs;
 295                 }
 296
 297                 # Whenever altering this array, please provide a covering test case
 298                 # in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 299                 static $attribDefaults = array(
 300                         'area' => array( 'shape' => 'rect' ),
 301                         'button' => array(
 302                                 'formaction' => 'GET',
 303                                 'formenctype' => 'application/x-www-form-urlencoded',
 304                                 'type' => 'submit',
 305                         ),
 306                         'canvas' => array(
 307                                 'height' => '150',
 308                                 'width' => '300',
 309                         ),
 310                         'command' => array( 'type' => 'command' ),
 311                         'form' => array(
 312                                 'action' => 'GET',
 313                                 'autocomplete' => 'on',
 314                                 'enctype' => 'application/x-www-form-urlencoded',
 315                         ),
 316                         'input' => array(
 317                                 'formaction' => 'GET',
 318                                 'type' => 'text',
 319                         ),
 320                         'keygen' => array( 'keytype' => 'rsa' ),
 321                         'link' => array( 'media' => 'all' ),
 322                         'menu' => array( 'type' => 'list' ),
 323                         # Note: the use of text/javascript here instead of other JavaScript
 324                         # MIME types follows the HTML5 spec.
 325                         'script' => array( 'type' => 'text/javascript' ),
 326                         'style' => array(
 327                                 'media' => 'all',
 328                                 'type' => 'text/css',
 329                         ),
 330                         'textarea' => array( 'wrap' => 'soft' ),
 331                 );
 332
 333                 $element = strtolower( $element );
 334
 335                 foreach ( $attribs as $attrib => $value ) {
 336                         $lcattrib = strtolower( $attrib );
 337                         if( is_array( $value ) ) {
 338                                 $value = implode( ' ', $value );
 339                         } else {
 340                                 $value = strval( $value );
 341                         }
 342
 343                         # Simple checks using $attribDefaults
 344                         if ( isset( $attribDefaults[$element][$lcattrib] ) &&
 345                         $attribDefaults[$element][$lcattrib] == $value ) {
 346                                 unset( $attribs[$attrib] );
 347                         }
 348
 349                         if ( $lcattrib == 'class' && $value == '' ) {
 350                                 unset( $attribs[$attrib] );
 351                         }
 352                 }
 353
 354                 # More subtle checks
 355                 if ( $element === 'link' && isset( $attribs['type'] )
 356                 && strval( $attribs['type'] ) == 'text/css' ) {
 357                         unset( $attribs['type'] );
 358                 }
 359                 if ( $element === 'input' ) {
 360                         $type = isset( $attribs['type'] ) ? $attribs['type'] : null;
 361                         $value = isset( $attribs['value'] ) ? $attribs['value'] : null;
 362                         if ( $type === 'checkbox' || $type === 'radio' ) {
 363                                 // The default value for checkboxes and radio buttons is 'on'
 364                                 // not ''. By stripping value="" we break radio boxes that
 365                                 // actually wants empty values.
 366                                 if ( $value === 'on' ) {
 367                                         unset( $attribs['value'] );
 368                                 }
 369                         } elseif ( $type === 'submit' ) {
 370                                 // The default value for submit appears to be "Submit" but
 371                                 // let's not bother stripping out localized text that matches
 372                                 // that.
 373                         } else {
 374                                 // The default value for nearly every other field type is ''
 375                                 // The 'range' and 'color' types use different defaults but
 376                                 // stripping a value="" does not hurt them.
 377                                 if ( $value === '' ) {
 378                                         unset( $attribs['value'] );
 379                                 }
 380                         }
 381                 }
 382                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 383                         if ( in_array( 'multiple', $attribs )
 384                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 385                         ) {
 386                                 # A multi-select
 387                                 if ( strval( $attribs['size'] ) == '4' ) {
 388                                         unset( $attribs['size'] );
 389                                 }
 390                         } else {
 391                                 # Single select
 392                                 if ( strval( $attribs['size'] ) == '1' ) {
 393                                         unset( $attribs['size'] );
 394                                 }
 395                         }
 396                 }
 397
 398                 return $attribs;
 399         }
 400
 401         /**
 402          * Given an associative array of element attributes, generate a string
 403          * to stick after the element name in HTML output.  Like array( 'href' =>
 404          * 'http://www.mediawiki.org/' ) becomes something like
 405          * ' href="http://www.mediawiki.org"'.  Again, this is like
 406          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 407          * For instance, it will omit quotation marks if $wgWellFormedXml is false,
 408          * and will treat boolean attributes specially.
 409          *
 410          * Attributes that should contain space-separated lists (such as 'class') array
 411          * values are allowed as well, which will automagically be normalized
 412          * and converted to a space-separated string. In addition to a numerical
 413          * array, the attribute value may also be an associative array. See the
 414          * example below for how that works.
 415          *
 416          * @par Numerical array
 417          * @code
 418          *     Html::element( 'em', array(
 419          *         'class' => array( 'foo', 'bar' )
 420          *     ) );
 421          *     // gives '<em class="foo bar"></em>'
 422          * @endcode
 423          *
 424          * @par Associative array
 425          * @code
 426          *     Html::element( 'em', array(
 427          *         'class' => array( 'foo', 'bar', 'foo' => false, 'quux' => true )
 428          *     ) );
 429          *     // gives '<em class="bar quux"></em>'
 430          * @endcode
 431          *
 432          * @param $attribs array Associative array of attributes, e.g., array(
 433          *   'href' => 'http://www.mediawiki.org/' ).  Values will be HTML-escaped.
 434          *   A value of false means to omit the attribute.  For boolean attributes,
 435          *   you can omit the key, e.g., array( 'checked' ) instead of
 436          *   array( 'checked' => 'checked' ) or such.
 437          * @return string HTML fragment that goes between element name and '>'
 438          *   (starting with a space if at least one attribute is output)
 439          */
 440         public static function expandAttributes( $attribs ) {
 441                 global $wgHtml5, $wgWellFormedXml;
 442
 443                 $ret = '';
 444                 $attribs = (array)$attribs;
 445                 foreach ( $attribs as $key => $value ) {
 446                         if ( $value === false || is_null( $value ) ) {
 447                                 continue;
 448                         }
 449
 450                         # For boolean attributes, support array( 'foo' ) instead of
 451                         # requiring array( 'foo' => 'meaningless' ).
 452                         if ( is_int( $key )
 453                         && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 454                                 $key = $value;
 455                         }
 456
 457                         # Not technically required in HTML5, but required in XHTML 1.0,
 458                         # and we'd like consistency and better compression anyway.
 459                         $key = strtolower( $key );
 460
 461                         # Here we're blacklisting some HTML5-only attributes...
 462                         if ( !$wgHtml5 && in_array( $key, self::$HTMLFiveOnlyAttribs )
 463                          ) {
 464                                 continue;
 465                         }
 466
 467                         # Bug 23769: Blacklist all form validation attributes for now.  Current
 468                         # (June 2010) WebKit has no UI, so the form just refuses to submit
 469                         # without telling the user why, which is much worse than failing
 470                         # server-side validation.  Opera is the only other implementation at
 471                         # this time, and has ugly UI, so just kill the feature entirely until
 472                         # we have at least one good implementation.
 473                         if ( in_array( $key, array( 'max', 'min', 'pattern', 'required', 'step' ) ) ) {
 474                                 continue;
 475                         }
 476
 477                         // http://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 478                         // http://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 479                         $spaceSeparatedListAttributes = array(
 480                                 'class', // html4, html5
 481                                 'accesskey', // as of html5, multiple space-separated values allowed
 482                                 // html4-spec doesn't document rel= as space-separated
 483                                 // but has been used like that and is now documented as such
 484                                 // in the html5-spec.
 485                                 'rel',
 486                         );
 487
 488                         # Specific features for attributes that allow a list of space-separated values
 489                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 490                                 // Apply some normalization and remove duplicates
 491
 492                                 // Convert into correct array. Array can contain space-seperated
 493                                 // values. Implode/explode to get those into the main array as well.
 494                                 if ( is_array( $value ) ) {
 495                                         // If input wasn't an array, we can skip this step
 496                                         $newValue = array();
 497                                         foreach ( $value as $k => $v ) {
 498                                                 if ( is_string( $v ) ) {
 499                                                         // String values should be normal `array( 'foo' )`
 500                                                         // Just append them
 501                                                         if ( !isset( $value[$v] ) ) {
 502                                                                 // As a special case don't set 'foo' if a
 503                                                                 // separate 'foo' => true/false exists in the array
 504                                                                 // keys should be authoritive
 505                                                                 $newValue[] = $v;
 506                                                         }
 507                                                 } elseif ( $v ) {
 508                                                         // If the value is truthy but not a string this is likely
 509                                                         // an array( 'foo' => true ), falsy values don't add strings
 510                                                         $newValue[] = $k;
 511                                                 }
 512                                         }
 513                                         $value = implode( ' ', $newValue );
 514                                 }
 515                                 $value = explode( ' ', $value );
 516
 517                                 // Normalize spacing by fixing up cases where people used
 518                                 // more than 1 space and/or a trailing/leading space
 519                                 $value = array_diff( $value, array( '', ' ' ) );
 520
 521                                 // Remove duplicates and create the string
 522                                 $value = implode( ' ', array_unique( $value ) );
 523                         }
 524
 525                         # See the "Attributes" section in the HTML syntax part of HTML5,
 526                         # 9.1.2.3 as of 2009-08-10.  Most attributes can have quotation
 527                         # marks omitted, but not all.  (Although a literal " is not
 528                         # permitted, we don't check for that, since it will be escaped
 529                         # anyway.)
 530                         #
 531                         # See also research done on further characters that need to be
 532                         # escaped: http://code.google.com/p/html5lib/issues/detail?id=93
 533                         $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}"
 534                                 . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}"
 535                                 . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}";
 536                         if ( $wgWellFormedXml || $value === ''
 537                         || preg_match( "![$badChars]!u", $value ) ) {
 538                                 $quote = '"';
 539                         } else {
 540                                 $quote = '';
 541                         }
 542
 543                         if ( in_array( $key, self::$boolAttribs ) ) {
 544                                 # In XHTML 1.0 Transitional, the value needs to be equal to the
 545                                 # key.  In HTML5, we can leave the value empty instead.  If we
 546                                 # don't need well-formed XML, we can omit the = entirely.
 547                                 if ( !$wgWellFormedXml ) {
 548                                         $ret .= " $key";
 549                                 } elseif ( $wgHtml5 ) {
 550                                         $ret .= " $key=\"\"";
 551                                 } else {
 552                                         $ret .= " $key=\"$key\"";
 553                                 }
 554                         } else {
 555                                 # Apparently we need to entity-encode \n, \r, \t, although the
 556                                 # spec doesn't mention that.  Since we're doing strtr() anyway,
 557                                 # and we don't need <> escaped here, we may as well not call
 558                                 # htmlspecialchars().
 559                                 # @todo FIXME: Verify that we actually need to
 560                                 # escape \n\r\t here, and explain why, exactly.
 561                                 #
 562                                 # We could call Sanitizer::encodeAttribute() for this, but we
 563                                 # don't because we're stubborn and like our marginal savings on
 564                                 # byte size from not having to encode unnecessary quotes.
 565                                 $map = array(
 566                                         '&' => '&amp;',
 567                                         '"' => '&quot;',
 568                                         "\n" => '&#10;',
 569                                         "\r" => '&#13;',
 570                                         "\t" => '&#9;'
 571                                 );
 572                                 if ( $wgWellFormedXml ) {
 573                                         # This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue>
 574                                         # But reportedly it breaks some XML tools?
 575                                         # @todo FIXME: Is this really true?
 576                                         $map['<'] = '&lt;';
 577                                 }
 578                                 $ret .= " $key=$quote" . strtr( $value, $map ) . $quote;
 579                         }
 580                 }
 581                 return $ret;
 582         }
 583
 584         /**
 585          * Output a "<script>" tag with the given contents.
 586          *
 587          * @todo do some useful escaping as well, like if $contents contains
 588          * literal "</script>" or (for XML) literal "]]>".
 589          *
 590          * @param $contents string JavaScript
 591          * @return string Raw HTML
 592          */
 593         public static function inlineScript( $contents ) {
 594                 global $wgHtml5, $wgJsMimeType, $wgWellFormedXml;
 595
 596                 $attrs = array();
 597
 598                 if ( !$wgHtml5 ) {
 599                         $attrs['type'] = $wgJsMimeType;
 600                 }
 601
 602                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 603                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 604                 }
 605
 606                 return self::rawElement( 'script', $attrs, $contents );
 607         }
 608
 609         /**
 610          * Output a "<script>" tag linking to the given URL, e.g.,
 611          * "<script src=foo.js></script>".
 612          *
 613          * @param $url string
 614          * @return string Raw HTML
 615          */
 616         public static function linkedScript( $url ) {
 617                 global $wgHtml5, $wgJsMimeType;
 618
 619                 $attrs = array( 'src' => $url );
 620
 621                 if ( !$wgHtml5 ) {
 622                         $attrs['type'] = $wgJsMimeType;
 623                 }
 624
 625                 return self::element( 'script', $attrs );
 626         }
 627
 628         /**
 629          * Output a "<style>" tag with the given contents for the given media type
 630          * (if any).  TODO: do some useful escaping as well, like if $contents
 631          * contains literal "</style>" (admittedly unlikely).
 632          *
 633          * @param $contents string CSS
 634          * @param $media mixed A media type string, like 'screen'
 635          * @return string Raw HTML
 636          */
 637         public static function inlineStyle( $contents, $media = 'all' ) {
 638                 global $wgWellFormedXml;
 639
 640                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 641                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 642                 }
 643
 644                 return self::rawElement( 'style', array(
 645                         'type' => 'text/css',
 646                         'media' => $media,
 647                 ), $contents );
 648         }
 649
 650         /**
 651          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 652          * media type (if any).
 653          *
 654          * @param $url string
 655          * @param $media mixed A media type string, like 'screen'
 656          * @return string Raw HTML
 657          */
 658         public static function linkedStyle( $url, $media = 'all' ) {
 659                 return self::element( 'link', array(
 660                         'rel' => 'stylesheet',
 661                         'href' => $url,
 662                         'type' => 'text/css',
 663                         'media' => $media,
 664                 ) );
 665         }
 666
 667         /**
 668          * Convenience function to produce an "<input>" element.  This supports the
 669          * new HTML5 input types and attributes, and will silently strip them if
 670          * $wgHtml5 is false.
 671          *
 672          * @param $name    string name attribute
 673          * @param $value   mixed  value attribute
 674          * @param $type    string type attribute
 675          * @param $attribs array  Associative array of miscellaneous extra
 676          *   attributes, passed to Html::element()
 677          * @return string Raw HTML
 678          */
 679         public static function input( $name, $value = '', $type = 'text', $attribs = array() ) {
 680                 $attribs['type'] = $type;
 681                 $attribs['value'] = $value;
 682                 $attribs['name'] = $name;
 683
 684                 return self::element( 'input', $attribs );
 685         }
 686
 687         /**
 688          * Convenience function to produce an input element with type=hidden
 689          *
 690          * @param $name    string name attribute
 691          * @param $value   string value attribute
 692          * @param $attribs array  Associative array of miscellaneous extra
 693          *   attributes, passed to Html::element()
 694          * @return string Raw HTML
 695          */
 696         public static function hidden( $name, $value, $attribs = array() ) {
 697                 return self::input( $name, $value, 'hidden', $attribs );
 698         }
 699
 700         /**
 701          * Convenience function to produce an "<input>" element.
 702          *
 703          * This supports leaving out the cols= and rows= which Xml requires and are
 704          * required by HTML4/XHTML but not required by HTML5 and will silently set
 705          * cols="" and rows="" if $wgHtml5 is false and cols and rows are omitted
 706          * (HTML4 validates present but empty cols="" and rows="" as valid).
 707          *
 708          * @param $name    string name attribute
 709          * @param $value   string value attribute
 710          * @param $attribs array  Associative array of miscellaneous extra
 711          *   attributes, passed to Html::element()
 712          * @return string Raw HTML
 713          */
 714         public static function textarea( $name, $value = '', $attribs = array() ) {
 715                 global $wgHtml5;
 716
 717                 $attribs['name'] = $name;
 718
 719                 if ( !$wgHtml5 ) {
 720                         if ( !isset( $attribs['cols'] ) ) {
 721                                 $attribs['cols'] = "";
 722                         }
 723
 724                         if ( !isset( $attribs['rows'] ) ) {
 725                                 $attribs['rows'] = "";
 726                         }
 727                 }
 728
 729                 if (substr($value, 0, 1) == "\n") {
 730                         // Workaround for bug 12130: browsers eat the initial newline
 731                         // assuming that it's just for show, but they do keep the later
 732                         // newlines, which we may want to preserve during editing.
 733                         // Prepending a single newline
 734                         $spacedValue = "\n" . $value;
 735                 } else {
 736                         $spacedValue = $value;
 737                 }
 738                 return self::element( 'textarea', $attribs, $spacedValue );
 739         }
 740         /**
 741          * Build a drop-down box for selecting a namespace
 742          *
 743          * @param $params array:
 744          * - selected: [optional] Id of namespace which should be pre-selected
 745          * - all: [optional] Value of item for "all namespaces". If null or unset, no "<option>" is generated to select all namespaces
 746          * - label: text for label to add before the field
 747          * - exclude: [optional] Array of namespace ids to exclude
 748          * - disable: [optional] Array of namespace ids for which the option should be disabled in the selector
 749          * @param $selectAttribs array HTML attributes for the generated select element.
 750          * - id:   [optional], default: 'namespace'
 751          * - name: [optional], default: 'namespace'
 752          * @return string HTML code to select a namespace.
 753          */
 754         public static function namespaceSelector( array $params = array(), array $selectAttribs = array() ) {
 755                 global $wgContLang;
 756
 757                 ksort( $selectAttribs );
 758
 759                 // Is a namespace selected?
 760                 if ( isset( $params['selected'] ) ) {
 761                         // If string only contains digits, convert to clean int. Selected could also
 762                         // be "all" or "" etc. which needs to be left untouched.
 763                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 764                         // and returns false for already clean ints. Use regex instead..
 765                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 766                                 $params['selected'] = intval( $params['selected'] );
 767                         }
 768                         // else: leaves it untouched for later processing
 769                 } else {
 770                         $params['selected'] = '';
 771                 }
 772
 773                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 774                         $params['exclude'] = array();
 775                 }
 776                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 777                         $params['disable'] = array();
 778                 }
 779
 780                 // Associative array between option-values and option-labels
 781                 $options = array();
 782
 783                 if ( isset( $params['all'] ) ) {
 784                         // add an option that would let the user select all namespaces.
 785                         // Value is provided by user, the name shown is localized for the user.
 786                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 787                 }
 788                 // Add all namespaces as options (in the content langauge)
 789                 $options += $wgContLang->getFormattedNamespaces();
 790
 791                 // Convert $options to HTML and filter out namespaces below 0
 792                 $optionsHtml = array();
 793                 foreach ( $options as $nsId => $nsName ) {
 794                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 795                                 continue;
 796                         }
 797                         if ( $nsId === NS_MAIN ) {
 798                                 // For other namespaces use use the namespace prefix as label, but for
 799                                 // main we don't use "" but the user message descripting it (e.g. "(Main)" or "(Article)")
 800                                 $nsName = wfMessage( 'blanknamespace' )->text();
 801                         } elseif ( is_int( $nsId ) ) {
 802                                 $nsName = $wgContLang->convertNamespace( $nsId );
 803                         }
 804                         $optionsHtml[] = Html::element(
 805                                 'option', array(
 806                                         'disabled' => in_array( $nsId, $params['disable'] ),
 807                                         'value' => $nsId,
 808                                         'selected' => $nsId === $params['selected'],
 809                                 ), $nsName
 810                         );
 811                 }
 812
 813                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 814                         $selectAttribs['id'] = 'namespace';
 815                 }
 816
 817                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 818                         $selectAttribs['name'] = 'namespace';
 819                 }
 820
 821                 $ret = '';
 822                 if ( isset( $params['label'] ) ) {
 823                         $ret .= Html::element(
 824                                 'label', array(
 825                                         'for' => isset( $selectAttribs['id'] ) ? $selectAttribs['id'] : null,
 826                                 ), $params['label']
 827                         ) . '&#160;';
 828                 }
 829
 830                 // Wrap options in a <select>
 831                 $ret .= Html::openElement( 'select', $selectAttribs )
 832                         . "\n"
 833                         . implode( "\n", $optionsHtml )
 834                         . "\n"
 835                         . Html::closeElement( 'select' );
 836
 837                 return $ret;
 838         }
 839
 840         /**
 841          * Constructs the opening html-tag with necessary doctypes depending on
 842          * global variables.
 843          *
 844          * @param $attribs array  Associative array of miscellaneous extra
 845          *   attributes, passed to Html::element() of html tag.
 846          * @return string  Raw HTML
 847          */
 848         public static function htmlHeader( $attribs = array() ) {
 849                 $ret = '';
 850
 851                 global $wgMimeType;
 852
 853                 if ( self::isXmlMimeType( $wgMimeType ) ) {
 854                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 855                 }
 856
 857                 global $wgHtml5, $wgHtml5Version, $wgDocType, $wgDTD;
 858                 global $wgXhtmlNamespaces, $wgXhtmlDefaultNamespace;
 859
 860                 if ( $wgHtml5 ) {
 861                         $ret .= "<!DOCTYPE html>\n";
 862
 863                         if ( $wgHtml5Version ) {
 864                                 $attribs['version'] = $wgHtml5Version;
 865                         }
 866                 } else {
 867                         $ret .= "<!DOCTYPE html PUBLIC \"$wgDocType\" \"$wgDTD\">\n";
 868                         $attribs['xmlns'] = $wgXhtmlDefaultNamespace;
 869
 870                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 871                                 $attribs["xmlns:$tag"] = $ns;
 872                         }
 873                 }
 874
 875                 $html = Html::openElement( 'html', $attribs );
 876
 877                 if ( $html ) {
 878                         $html .= "\n";
 879                 }
 880
 881                 $ret .= $html;
 882
 883                 return $ret;
 884         }
 885
 886         /**
 887          * Determines if the given mime type is xml.
 888          *
 889          * @param $mimetype    string MimeType
 890          * @return Boolean
 891          */
 892         public static function isXmlMimeType( $mimetype ) {
 893                 switch ( $mimetype ) {
 894                         case 'text/xml':
 895                         case 'application/xhtml+xml':
 896                         case 'application/xml':
 897                                 return true;
 898                         default:
 899                                 return false;
 900                 }
 901         }
 902
 903         /**
 904          * Get HTML for an info box with an icon.
 905          *
 906          * @param $text String: wikitext, get this with wfMessage()->plain()
 907          * @param $icon String: icon name, file in skins/common/images
 908          * @param $alt String: alternate text for the icon
 909          * @param $class String: additional class name to add to the wrapper div
 910          * @param $useStylePath
 911          *
 912          * @return string
 913          */
 914         static function infoBox( $text, $icon, $alt, $class = false, $useStylePath = true ) {
 915                 global $wgStylePath;
 916
 917                 if ( $useStylePath ) {
 918                         $icon = $wgStylePath.'/common/images/'.$icon;
 919                 }
 920
 921                 $s  = Html::openElement( 'div', array( 'class' => "mw-infobox $class") );
 922
 923                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-left' ) ).
 924                                 Html::element( 'img',
 925                                         array(
 926                                                 'src' => $icon,
 927                                                 'alt' => $alt,
 928                                         )
 929                                 ).
 930                                 Html::closeElement( 'div' );
 931
 932                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-right' ) ).
 933                                 $text.
 934                                 Html::closeElement( 'div' );
 935                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
 936
 937                 $s .= Html::closeElement( 'div' );
 938
 939                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
 940
 941                 return $s;
 942         }
 943
 944         /**
 945          * Generate a srcset attribute value from an array mapping pixel densities
 946          * to URLs. Note that srcset supports width and height values as well, which
 947          * are not used here.
 948          *
 949          * @param array $urls
 950          * @return string
 951          */
 952         static function srcSet( $urls ) {
 953                 $candidates = array();
 954                 foreach( $urls as $density => $url ) {
 955                         // Image candidate syntax per current whatwg live spec, 2012-09-23:
 956                         // http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded-content-1.html#attr-img-srcset
 957                         $candidates[] = "{$url} {$density}x";
 958                 }
 959                 return implode( ", ", $candidates );
 960         }
 961 }