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                 // According to standard the default type for <button> elements is "submit".
 238                 // Depending on compatibility mode IE might use "button", instead.
 239                 // We enforce the standard "submit".
 240                 if ( $element == 'button' && !isset( $attribs['type'] ) ) {
 241                         $attribs['type'] = 'submit';
 242                 }
 243
 244                 return "<$element" . self::expandAttributes(
 245                         self::dropDefaults( $element, $attribs ) ) . '>';
 246         }
 247
 248         /**
 249          * Returns "</$element>", except if $wgWellFormedXml is off, in which case
 250          * it returns the empty string when that's guaranteed to be safe.
 251          *
 252          * @since 1.17
 253          * @param $element string Name of the element, e.g., 'a'
 254          * @return string A closing tag, if required
 255          */
 256         public static function closeElement( $element ) {
 257                 global $wgWellFormedXml;
 258
 259                 $element = strtolower( $element );
 260
 261                 // Reference:
 262                 // http://www.whatwg.org/specs/web-apps/current-work/multipage/syntax.html#optional-tags
 263                 if ( !$wgWellFormedXml && in_array( $element, array(
 264                         'html',
 265                         'head',
 266                         'body',
 267                         'li',
 268                         'dt',
 269                         'dd',
 270                         'tr',
 271                         'td',
 272                         'th',
 273                 ) ) ) {
 274                         return '';
 275                 }
 276                 return "</$element>";
 277         }
 278
 279         /**
 280          * Given an element name and an associative array of element attributes,
 281          * return an array that is functionally identical to the input array, but
 282          * possibly smaller.  In particular, attributes might be stripped if they
 283          * are given their default values.
 284          *
 285          * This method is not guaranteed to remove all redundant attributes, only
 286          * some common ones and some others selected arbitrarily at random.  It
 287          * only guarantees that the output array should be functionally identical
 288          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 289          *
 290          * @param $element string Name of the element, e.g., 'a'
 291          * @param $attribs array  Associative array of attributes, e.g., array(
 292          *   'href' => 'http://www.mediawiki.org/' ).  See expandAttributes() for
 293          *   further documentation.
 294          * @return array An array of attributes functionally identical to $attribs
 295          */
 296         private static function dropDefaults( $element, $attribs ) {
 297                 // Don't bother doing anything if we aren't outputting HTML5; it's too
 298                 // much of a pain to maintain two sets of defaults.
 299                 global $wgHtml5;
 300                 if ( !$wgHtml5 ) {
 301                         return $attribs;
 302                 }
 303
 304                 // Whenever altering this array, please provide a covering test case
 305                 // in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 306                 static $attribDefaults = array(
 307                         'area' => array( 'shape' => 'rect' ),
 308                         'button' => array(
 309                                 'formaction' => 'GET',
 310                                 'formenctype' => 'application/x-www-form-urlencoded',
 311                         ),
 312                         'canvas' => array(
 313                                 'height' => '150',
 314                                 'width' => '300',
 315                         ),
 316                         'command' => array( 'type' => 'command' ),
 317                         'form' => array(
 318                                 'action' => 'GET',
 319                                 'autocomplete' => 'on',
 320                                 'enctype' => 'application/x-www-form-urlencoded',
 321                         ),
 322                         'input' => array(
 323                                 'formaction' => 'GET',
 324                                 'type' => 'text',
 325                         ),
 326                         'keygen' => array( 'keytype' => 'rsa' ),
 327                         'link' => array( 'media' => 'all' ),
 328                         'menu' => array( 'type' => 'list' ),
 329                         // Note: the use of text/javascript here instead of other JavaScript
 330                         // MIME types follows the HTML5 spec.
 331                         'script' => array( 'type' => 'text/javascript' ),
 332                         'style' => array(
 333                                 'media' => 'all',
 334                                 'type' => 'text/css',
 335                         ),
 336                         'textarea' => array( 'wrap' => 'soft' ),
 337                 );
 338
 339                 $element = strtolower( $element );
 340
 341                 foreach ( $attribs as $attrib => $value ) {
 342                         $lcattrib = strtolower( $attrib );
 343                         if( is_array( $value ) ) {
 344                                 $value = implode( ' ', $value );
 345                         } else {
 346                                 $value = strval( $value );
 347                         }
 348
 349                         // Simple checks using $attribDefaults
 350                         if ( isset( $attribDefaults[$element][$lcattrib] ) &&
 351                         $attribDefaults[$element][$lcattrib] == $value ) {
 352                                 unset( $attribs[$attrib] );
 353                         }
 354
 355                         if ( $lcattrib == 'class' && $value == '' ) {
 356                                 unset( $attribs[$attrib] );
 357                         }
 358                 }
 359
 360                 // More subtle checks
 361                 if ( $element === 'link' && isset( $attribs['type'] )
 362                 && strval( $attribs['type'] ) == 'text/css' ) {
 363                         unset( $attribs['type'] );
 364                 }
 365                 if ( $element === 'input' ) {
 366                         $type = isset( $attribs['type'] ) ? $attribs['type'] : null;
 367                         $value = isset( $attribs['value'] ) ? $attribs['value'] : null;
 368                         if ( $type === 'checkbox' || $type === 'radio' ) {
 369                                 // The default value for checkboxes and radio buttons is 'on'
 370                                 // not ''. By stripping value="" we break radio boxes that
 371                                 // actually wants empty values.
 372                                 if ( $value === 'on' ) {
 373                                         unset( $attribs['value'] );
 374                                 }
 375                         } elseif ( $type === 'submit' ) {
 376                                 // The default value for submit appears to be "Submit" but
 377                                 // let's not bother stripping out localized text that matches
 378                                 // that.
 379                         } else {
 380                                 // The default value for nearly every other field type is ''
 381                                 // The 'range' and 'color' types use different defaults but
 382                                 // stripping a value="" does not hurt them.
 383                                 if ( $value === '' ) {
 384                                         unset( $attribs['value'] );
 385                                 }
 386                         }
 387                 }
 388                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 389                         if ( in_array( 'multiple', $attribs )
 390                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 391                         ) {
 392                                 // A multi-select
 393                                 if ( strval( $attribs['size'] ) == '4' ) {
 394                                         unset( $attribs['size'] );
 395                                 }
 396                         } else {
 397                                 // Single select
 398                                 if ( strval( $attribs['size'] ) == '1' ) {
 399                                         unset( $attribs['size'] );
 400                                 }
 401                         }
 402                 }
 403
 404                 return $attribs;
 405         }
 406
 407         /**
 408          * Given an associative array of element attributes, generate a string
 409          * to stick after the element name in HTML output.  Like array( 'href' =>
 410          * 'http://www.mediawiki.org/' ) becomes something like
 411          * ' href="http://www.mediawiki.org"'.  Again, this is like
 412          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 413          * For instance, it will omit quotation marks if $wgWellFormedXml is false,
 414          * and will treat boolean attributes specially.
 415          *
 416          * Attributes that should contain space-separated lists (such as 'class') array
 417          * values are allowed as well, which will automagically be normalized
 418          * and converted to a space-separated string. In addition to a numerical
 419          * array, the attribute value may also be an associative array. See the
 420          * example below for how that works.
 421          *
 422          * @par Numerical array
 423          * @code
 424          *     Html::element( 'em', array(
 425          *         'class' => array( 'foo', 'bar' )
 426          *     ) );
 427          *     // gives '<em class="foo bar"></em>'
 428          * @endcode
 429          *
 430          * @par Associative array
 431          * @code
 432          *     Html::element( 'em', array(
 433          *         'class' => array( 'foo', 'bar', 'foo' => false, 'quux' => true )
 434          *     ) );
 435          *     // gives '<em class="bar quux"></em>'
 436          * @endcode
 437          *
 438          * @param $attribs array Associative array of attributes, e.g., array(
 439          *   'href' => 'http://www.mediawiki.org/' ).  Values will be HTML-escaped.
 440          *   A value of false means to omit the attribute.  For boolean attributes,
 441          *   you can omit the key, e.g., array( 'checked' ) instead of
 442          *   array( 'checked' => 'checked' ) or such.
 443          * @return string HTML fragment that goes between element name and '>'
 444          *   (starting with a space if at least one attribute is output)
 445          */
 446         public static function expandAttributes( $attribs ) {
 447                 global $wgHtml5, $wgWellFormedXml;
 448
 449                 $ret = '';
 450                 $attribs = (array)$attribs;
 451                 foreach ( $attribs as $key => $value ) {
 452                         if ( $value === false || is_null( $value ) ) {
 453                                 continue;
 454                         }
 455
 456                         // For boolean attributes, support array( 'foo' ) instead of
 457                         // requiring array( 'foo' => 'meaningless' ).
 458                         if ( is_int( $key )
 459                         && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 460                                 $key = $value;
 461                         }
 462
 463                         // Not technically required in HTML5, but required in XHTML 1.0,
 464                         // and we'd like consistency and better compression anyway.
 465                         $key = strtolower( $key );
 466
 467                         // Here we're blacklisting some HTML5-only attributes...
 468                         if ( !$wgHtml5 && in_array( $key, self::$HTMLFiveOnlyAttribs )
 469                          ) {
 470                                 continue;
 471                         }
 472
 473                         // Bug 23769: Blacklist all form validation attributes for now.  Current
 474                         // (June 2010) WebKit has no UI, so the form just refuses to submit
 475                         // without telling the user why, which is much worse than failing
 476                         // server-side validation.  Opera is the only other implementation at
 477                         // this time, and has ugly UI, so just kill the feature entirely until
 478                         // we have at least one good implementation.
 479
 480                         // As the default value of "1" for "step" rejects decimal
 481                         // numbers to be entered in 'type="number"' fields, allow
 482                         // the special case 'step="any"'.
 483
 484                         if ( in_array( $key, array( 'max', 'min', 'pattern', 'required' ) ) ||
 485                                  $key === 'step' && $value !== 'any' ) {
 486                                 continue;
 487                         }
 488
 489                         // http://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 490                         // http://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 491                         $spaceSeparatedListAttributes = array(
 492                                 'class', // html4, html5
 493                                 'accesskey', // as of html5, multiple space-separated values allowed
 494                                 // html4-spec doesn't document rel= as space-separated
 495                                 // but has been used like that and is now documented as such
 496                                 // in the html5-spec.
 497                                 'rel',
 498                         );
 499
 500                         // Specific features for attributes that allow a list of space-separated values
 501                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 502                                 // Apply some normalization and remove duplicates
 503
 504                                 // Convert into correct array. Array can contain space-seperated
 505                                 // values. Implode/explode to get those into the main array as well.
 506                                 if ( is_array( $value ) ) {
 507                                         // If input wasn't an array, we can skip this step
 508                                         $newValue = array();
 509                                         foreach ( $value as $k => $v ) {
 510                                                 if ( is_string( $v ) ) {
 511                                                         // String values should be normal `array( 'foo' )`
 512                                                         // Just append them
 513                                                         if ( !isset( $value[$v] ) ) {
 514                                                                 // As a special case don't set 'foo' if a
 515                                                                 // separate 'foo' => true/false exists in the array
 516                                                                 // keys should be authoritive
 517                                                                 $newValue[] = $v;
 518                                                         }
 519                                                 } elseif ( $v ) {
 520                                                         // If the value is truthy but not a string this is likely
 521                                                         // an array( 'foo' => true ), falsy values don't add strings
 522                                                         $newValue[] = $k;
 523                                                 }
 524                                         }
 525                                         $value = implode( ' ', $newValue );
 526                                 }
 527                                 $value = explode( ' ', $value );
 528
 529                                 // Normalize spacing by fixing up cases where people used
 530                                 // more than 1 space and/or a trailing/leading space
 531                                 $value = array_diff( $value, array( '', ' ' ) );
 532
 533                                 // Remove duplicates and create the string
 534                                 $value = implode( ' ', array_unique( $value ) );
 535                         }
 536
 537                         // See the "Attributes" section in the HTML syntax part of HTML5,
 538                         // 9.1.2.3 as of 2009-08-10.  Most attributes can have quotation
 539                         // marks omitted, but not all.  (Although a literal " is not
 540                         // permitted, we don't check for that, since it will be escaped
 541                         // anyway.)
 542                         #
 543                         // See also research done on further characters that need to be
 544                         // escaped: http://code.google.com/p/html5lib/issues/detail?id=93
 545                         $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}"
 546                                 . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}"
 547                                 . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}";
 548                         if ( $wgWellFormedXml || $value === ''
 549                         || preg_match( "![$badChars]!u", $value ) ) {
 550                                 $quote = '"';
 551                         } else {
 552                                 $quote = '';
 553                         }
 554
 555                         if ( in_array( $key, self::$boolAttribs ) ) {
 556                                 // In XHTML 1.0 Transitional, the value needs to be equal to the
 557                                 // key.  In HTML5, we can leave the value empty instead.  If we
 558                                 // don't need well-formed XML, we can omit the = entirely.
 559                                 if ( !$wgWellFormedXml ) {
 560                                         $ret .= " $key";
 561                                 } elseif ( $wgHtml5 ) {
 562                                         $ret .= " $key=\"\"";
 563                                 } else {
 564                                         $ret .= " $key=\"$key\"";
 565                                 }
 566                         } else {
 567                                 // Apparently we need to entity-encode \n, \r, \t, although the
 568                                 // spec doesn't mention that.  Since we're doing strtr() anyway,
 569                                 // and we don't need <> escaped here, we may as well not call
 570                                 // htmlspecialchars().
 571                                 // @todo FIXME: Verify that we actually need to
 572                                 // escape \n\r\t here, and explain why, exactly.
 573                                 #
 574                                 // We could call Sanitizer::encodeAttribute() for this, but we
 575                                 // don't because we're stubborn and like our marginal savings on
 576                                 // byte size from not having to encode unnecessary quotes.
 577                                 $map = array(
 578                                         '&' => '&amp;',
 579                                         '"' => '&quot;',
 580                                         "\n" => '&#10;',
 581                                         "\r" => '&#13;',
 582                                         "\t" => '&#9;'
 583                                 );
 584                                 if ( $wgWellFormedXml ) {
 585                                         // This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue>
 586                                         // But reportedly it breaks some XML tools?
 587                                         // @todo FIXME: Is this really true?
 588                                         $map['<'] = '&lt;';
 589                                 }
 590                                 $ret .= " $key=$quote" . strtr( $value, $map ) . $quote;
 591                         }
 592                 }
 593                 return $ret;
 594         }
 595
 596         /**
 597          * Output a "<script>" tag with the given contents.
 598          *
 599          * @todo do some useful escaping as well, like if $contents contains
 600          * literal "</script>" or (for XML) literal "]]>".
 601          *
 602          * @param $contents string JavaScript
 603          * @return string Raw HTML
 604          */
 605         public static function inlineScript( $contents ) {
 606                 global $wgHtml5, $wgJsMimeType, $wgWellFormedXml;
 607
 608                 $attrs = array();
 609
 610                 if ( !$wgHtml5 ) {
 611                         $attrs['type'] = $wgJsMimeType;
 612                 }
 613
 614                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 615                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 616                 }
 617
 618                 return self::rawElement( 'script', $attrs, $contents );
 619         }
 620
 621         /**
 622          * Output a "<script>" tag linking to the given URL, e.g.,
 623          * "<script src=foo.js></script>".
 624          *
 625          * @param $url string
 626          * @return string Raw HTML
 627          */
 628         public static function linkedScript( $url ) {
 629                 global $wgHtml5, $wgJsMimeType;
 630
 631                 $attrs = array( 'src' => $url );
 632
 633                 if ( !$wgHtml5 ) {
 634                         $attrs['type'] = $wgJsMimeType;
 635                 }
 636
 637                 return self::element( 'script', $attrs );
 638         }
 639
 640         /**
 641          * Output a "<style>" tag with the given contents for the given media type
 642          * (if any).  TODO: do some useful escaping as well, like if $contents
 643          * contains literal "</style>" (admittedly unlikely).
 644          *
 645          * @param $contents string CSS
 646          * @param $media mixed A media type string, like 'screen'
 647          * @return string Raw HTML
 648          */
 649         public static function inlineStyle( $contents, $media = 'all' ) {
 650                 global $wgWellFormedXml;
 651
 652                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 653                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 654                 }
 655
 656                 return self::rawElement( 'style', array(
 657                         'type' => 'text/css',
 658                         'media' => $media,
 659                 ), $contents );
 660         }
 661
 662         /**
 663          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 664          * media type (if any).
 665          *
 666          * @param $url string
 667          * @param $media mixed A media type string, like 'screen'
 668          * @return string Raw HTML
 669          */
 670         public static function linkedStyle( $url, $media = 'all' ) {
 671                 return self::element( 'link', array(
 672                         'rel' => 'stylesheet',
 673                         'href' => $url,
 674                         'type' => 'text/css',
 675                         'media' => $media,
 676                 ) );
 677         }
 678
 679         /**
 680          * Convenience function to produce an "<input>" element.  This supports the
 681          * new HTML5 input types and attributes, and will silently strip them if
 682          * $wgHtml5 is false.
 683          *
 684          * @param $name    string name attribute
 685          * @param $value   mixed  value attribute
 686          * @param $type    string type attribute
 687          * @param $attribs array  Associative array of miscellaneous extra
 688          *   attributes, passed to Html::element()
 689          * @return string Raw HTML
 690          */
 691         public static function input( $name, $value = '', $type = 'text', $attribs = array() ) {
 692                 $attribs['type'] = $type;
 693                 $attribs['value'] = $value;
 694                 $attribs['name'] = $name;
 695
 696                 return self::element( 'input', $attribs );
 697         }
 698
 699         /**
 700          * Convenience function to produce an input element with type=hidden
 701          *
 702          * @param $name    string name attribute
 703          * @param $value   string value attribute
 704          * @param $attribs array  Associative array of miscellaneous extra
 705          *   attributes, passed to Html::element()
 706          * @return string Raw HTML
 707          */
 708         public static function hidden( $name, $value, $attribs = array() ) {
 709                 return self::input( $name, $value, 'hidden', $attribs );
 710         }
 711
 712         /**
 713          * Convenience function to produce an "<input>" element.
 714          *
 715          * This supports leaving out the cols= and rows= which Xml requires and are
 716          * required by HTML4/XHTML but not required by HTML5 and will silently set
 717          * cols="" and rows="" if $wgHtml5 is false and cols and rows are omitted
 718          * (HTML4 validates present but empty cols="" and rows="" as valid).
 719          *
 720          * @param $name    string name attribute
 721          * @param $value   string value attribute
 722          * @param $attribs array  Associative array of miscellaneous extra
 723          *   attributes, passed to Html::element()
 724          * @return string Raw HTML
 725          */
 726         public static function textarea( $name, $value = '', $attribs = array() ) {
 727                 global $wgHtml5;
 728
 729                 $attribs['name'] = $name;
 730
 731                 if ( !$wgHtml5 ) {
 732                         if ( !isset( $attribs['cols'] ) ) {
 733                                 $attribs['cols'] = "";
 734                         }
 735
 736                         if ( !isset( $attribs['rows'] ) ) {
 737                                 $attribs['rows'] = "";
 738                         }
 739                 }
 740
 741                 if (substr($value, 0, 1) == "\n") {
 742                         // Workaround for bug 12130: browsers eat the initial newline
 743                         // assuming that it's just for show, but they do keep the later
 744                         // newlines, which we may want to preserve during editing.
 745                         // Prepending a single newline
 746                         $spacedValue = "\n" . $value;
 747                 } else {
 748                         $spacedValue = $value;
 749                 }
 750                 return self::element( 'textarea', $attribs, $spacedValue );
 751         }
 752         /**
 753          * Build a drop-down box for selecting a namespace
 754          *
 755          * @param $params array:
 756          * - selected: [optional] Id of namespace which should be pre-selected
 757          * - all: [optional] Value of item for "all namespaces". If null or unset, no "<option>" is generated to select all namespaces
 758          * - label: text for label to add before the field
 759          * - exclude: [optional] Array of namespace ids to exclude
 760          * - disable: [optional] Array of namespace ids for which the option should be disabled in the selector
 761          * @param $selectAttribs array HTML attributes for the generated select element.
 762          * - id:   [optional], default: 'namespace'
 763          * - name: [optional], default: 'namespace'
 764          * @return string HTML code to select a namespace.
 765          */
 766         public static function namespaceSelector( array $params = array(), array $selectAttribs = array() ) {
 767                 global $wgContLang;
 768
 769                 ksort( $selectAttribs );
 770
 771                 // Is a namespace selected?
 772                 if ( isset( $params['selected'] ) ) {
 773                         // If string only contains digits, convert to clean int. Selected could also
 774                         // be "all" or "" etc. which needs to be left untouched.
 775                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 776                         // and returns false for already clean ints. Use regex instead..
 777                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 778                                 $params['selected'] = intval( $params['selected'] );
 779                         }
 780                         // else: leaves it untouched for later processing
 781                 } else {
 782                         $params['selected'] = '';
 783                 }
 784
 785                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 786                         $params['exclude'] = array();
 787                 }
 788                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 789                         $params['disable'] = array();
 790                 }
 791
 792                 // Associative array between option-values and option-labels
 793                 $options = array();
 794
 795                 if ( isset( $params['all'] ) ) {
 796                         // add an option that would let the user select all namespaces.
 797                         // Value is provided by user, the name shown is localized for the user.
 798                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 799                 }
 800                 // Add all namespaces as options (in the content langauge)
 801                 $options += $wgContLang->getFormattedNamespaces();
 802
 803                 // Convert $options to HTML and filter out namespaces below 0
 804                 $optionsHtml = array();
 805                 foreach ( $options as $nsId => $nsName ) {
 806                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 807                                 continue;
 808                         }
 809                         if ( $nsId === NS_MAIN ) {
 810                                 // For other namespaces use use the namespace prefix as label, but for
 811                                 // main we don't use "" but the user message descripting it (e.g. "(Main)" or "(Article)")
 812                                 $nsName = wfMessage( 'blanknamespace' )->text();
 813                         } elseif ( is_int( $nsId ) ) {
 814                                 $nsName = $wgContLang->convertNamespace( $nsId );
 815                         }
 816                         $optionsHtml[] = Html::element(
 817                                 'option', array(
 818                                         'disabled' => in_array( $nsId, $params['disable'] ),
 819                                         'value' => $nsId,
 820                                         'selected' => $nsId === $params['selected'],
 821                                 ), $nsName
 822                         );
 823                 }
 824
 825                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 826                         $selectAttribs['id'] = 'namespace';
 827                 }
 828
 829                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 830                         $selectAttribs['name'] = 'namespace';
 831                 }
 832
 833                 $ret = '';
 834                 if ( isset( $params['label'] ) ) {
 835                         $ret .= Html::element(
 836                                 'label', array(
 837                                         'for' => isset( $selectAttribs['id'] ) ? $selectAttribs['id'] : null,
 838                                 ), $params['label']
 839                         ) . '&#160;';
 840                 }
 841
 842                 // Wrap options in a <select>
 843                 $ret .= Html::openElement( 'select', $selectAttribs )
 844                         . "\n"
 845                         . implode( "\n", $optionsHtml )
 846                         . "\n"
 847                         . Html::closeElement( 'select' );
 848
 849                 return $ret;
 850         }
 851
 852         /**
 853          * Constructs the opening html-tag with necessary doctypes depending on
 854          * global variables.
 855          *
 856          * @param $attribs array  Associative array of miscellaneous extra
 857          *   attributes, passed to Html::element() of html tag.
 858          * @return string  Raw HTML
 859          */
 860         public static function htmlHeader( $attribs = array() ) {
 861                 $ret = '';
 862
 863                 global $wgMimeType;
 864
 865                 if ( self::isXmlMimeType( $wgMimeType ) ) {
 866                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 867                 }
 868
 869                 global $wgHtml5, $wgHtml5Version, $wgDocType, $wgDTD;
 870                 global $wgXhtmlNamespaces, $wgXhtmlDefaultNamespace;
 871
 872                 if ( $wgHtml5 ) {
 873                         $ret .= "<!DOCTYPE html>\n";
 874
 875                         if ( $wgHtml5Version ) {
 876                                 $attribs['version'] = $wgHtml5Version;
 877                         }
 878                 } else {
 879                         $ret .= "<!DOCTYPE html PUBLIC \"$wgDocType\" \"$wgDTD\">\n";
 880                         $attribs['xmlns'] = $wgXhtmlDefaultNamespace;
 881
 882                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 883                                 $attribs["xmlns:$tag"] = $ns;
 884                         }
 885                 }
 886
 887                 $html = Html::openElement( 'html', $attribs );
 888
 889                 if ( $html ) {
 890                         $html .= "\n";
 891                 }
 892
 893                 $ret .= $html;
 894
 895                 return $ret;
 896         }
 897
 898         /**
 899          * Determines if the given mime type is xml.
 900          *
 901          * @param $mimetype    string MimeType
 902          * @return Boolean
 903          */
 904         public static function isXmlMimeType( $mimetype ) {
 905                 switch ( $mimetype ) {
 906                         case 'text/xml':
 907                         case 'application/xhtml+xml':
 908                         case 'application/xml':
 909                                 return true;
 910                         default:
 911                                 return false;
 912                 }
 913         }
 914
 915         /**
 916          * Get HTML for an info box with an icon.
 917          *
 918          * @param $text String: wikitext, get this with wfMessage()->plain()
 919          * @param $icon String: icon name, file in skins/common/images
 920          * @param $alt String: alternate text for the icon
 921          * @param $class String: additional class name to add to the wrapper div
 922          * @param $useStylePath
 923          *
 924          * @return string
 925          */
 926         static function infoBox( $text, $icon, $alt, $class = false, $useStylePath = true ) {
 927                 global $wgStylePath;
 928
 929                 if ( $useStylePath ) {
 930                         $icon = $wgStylePath.'/common/images/'.$icon;
 931                 }
 932
 933                 $s  = Html::openElement( 'div', array( 'class' => "mw-infobox $class") );
 934
 935                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-left' ) ).
 936                                 Html::element( 'img',
 937                                         array(
 938                                                 'src' => $icon,
 939                                                 'alt' => $alt,
 940                                         )
 941                                 ).
 942                                 Html::closeElement( 'div' );
 943
 944                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-right' ) ).
 945                                 $text.
 946                                 Html::closeElement( 'div' );
 947                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
 948
 949                 $s .= Html::closeElement( 'div' );
 950
 951                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
 952
 953                 return $s;
 954         }
 955
 956         /**
 957          * Generate a srcset attribute value from an array mapping pixel densities
 958          * to URLs. Note that srcset supports width and height values as well, which
 959          * are not used here.
 960          *
 961          * @param array $urls
 962          * @return string
 963          */
 964         static function srcSet( $urls ) {
 965                 $candidates = array();
 966                 foreach( $urls as $density => $url ) {
 967                         // Image candidate syntax per current whatwg live spec, 2012-09-23:
 968                         // http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded-content-1.html#attr-img-srcset
 969                         $candidates[] = "{$url} {$density}x";
 970                 }
 971                 return implode( ", ", $candidates );
 972         }
 973 }