includes/Html.php

   1 <?php
   2 /**
   3  * Collection of methods to generate HTML content
   4  *
   5  * Copyright © 2009 Aryeh Gregor
   6  * http://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  */
  25
  26 /**
  27  * This class is a collection of static functions that serve two purposes:
  28  *
  29  * 1) Implement any algorithms specified by HTML5, or other HTML
  30  * specifications, in a convenient and self-contained way.
  31  *
  32  * 2) Allow HTML elements to be conveniently and safely generated, like the
  33  * current Xml class but a) less confused (Xml supports HTML-specific things,
  34  * but only sometimes!) and b) not necessarily confined to XML-compatible
  35  * output.
  36  *
  37  * There are two important configuration options this class uses:
  38  *
  39  * $wgMimeType: If this is set to an xml MIME type then output should be
  40  *     valid XHTML5.
  41  * $wgWellFormedXml: If this is set to true, then all output should be
  42  *     well-formed XML (quotes on attributes, self-closing tags, etc.).
  43  *
  44  * This class is meant to be confined to utility functions that are called from
  45  * trusted code paths.  It does not do enforcement of policy like not allowing
  46  * <a> elements.
  47  *
  48  * @since 1.16
  49  */
  50 class Html {
  51         // List of void elements from HTML5, section 8.1.2 as of 2011-08-12
  52         private static $voidElements = array(
  53                 'area',
  54                 'base',
  55                 'br',
  56                 'col',
  57                 'command',
  58                 'embed',
  59                 'hr',
  60                 'img',
  61                 'input',
  62                 'keygen',
  63                 'link',
  64                 'meta',
  65                 'param',
  66                 'source',
  67                 'track',
  68                 'wbr',
  69         );
  70
  71         // Boolean attributes, which may have the value omitted entirely.  Manually
  72         // collected from the HTML5 spec as of 2011-08-12.
  73         private static $boolAttribs = array(
  74                 'async',
  75                 'autofocus',
  76                 'autoplay',
  77                 'checked',
  78                 'controls',
  79                 'default',
  80                 'defer',
  81                 'disabled',
  82                 'formnovalidate',
  83                 'hidden',
  84                 'ismap',
  85                 'itemscope',
  86                 'loop',
  87                 'multiple',
  88                 'muted',
  89                 'novalidate',
  90                 'open',
  91                 'pubdate',
  92                 'readonly',
  93                 'required',
  94                 'reversed',
  95                 'scoped',
  96                 'seamless',
  97                 'selected',
  98                 'truespeed',
  99                 'typemustmatch',
 100                 // HTML5 Microdata
 101                 'itemscope',
 102         );
 103
 104         /**
 105          * Returns an HTML element in a string.  The major advantage here over
 106          * manually typing out the HTML is that it will escape all attribute
 107          * values.  If you're hardcoding all the attributes, or there are none, you
 108          * should probably just type out the html element yourself.
 109          *
 110          * This is quite similar to Xml::tags(), but it implements some useful
 111          * HTML-specific logic.  For instance, there is no $allowShortTag
 112          * parameter: the closing tag is magically omitted if $element has an empty
 113          * content model.  If $wgWellFormedXml is false, then a few bytes will be
 114          * shaved off the HTML output as well.
 115          *
 116          * @param string $element The element's name, e.g., 'a'
 117          * @param array $attribs Associative array of attributes, e.g., array(
 118          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 119          *   further documentation.
 120          * @param string $contents The raw HTML contents of the element: *not*
 121          *   escaped!
 122          * @return string Raw HTML
 123          */
 124         public static function rawElement( $element, $attribs = array(), $contents = '' ) {
 125                 global $wgWellFormedXml;
 126                 $start = self::openElement( $element, $attribs );
 127                 if ( in_array( $element, self::$voidElements ) ) {
 128                         if ( $wgWellFormedXml ) {
 129                                 // Silly XML.
 130                                 return substr( $start, 0, -1 ) . ' />';
 131                         }
 132                         return $start;
 133                 } else {
 134                         return "$start$contents" . self::closeElement( $element );
 135                 }
 136         }
 137
 138         /**
 139          * Identical to rawElement(), but HTML-escapes $contents (like
 140          * Xml::element()).
 141          *
 142          * @param string $element
 143          * @param array $attribs
 144          * @param string $contents
 145          *
 146          * @return string
 147          */
 148         public static function element( $element, $attribs = array(), $contents = '' ) {
 149                 return self::rawElement( $element, $attribs, strtr( $contents, array(
 150                         // There's no point in escaping quotes, >, etc. in the contents of
 151                         // elements.
 152                         '&' => '&amp;',
 153                         '<' => '&lt;'
 154                 ) ) );
 155         }
 156
 157         /**
 158          * Identical to rawElement(), but has no third parameter and omits the end
 159          * tag (and the self-closing '/' in XML mode for empty elements).
 160          *
 161          * @param string $element
 162          * @param array $attribs
 163          *
 164          * @return string
 165          */
 166         public static function openElement( $element, $attribs = array() ) {
 167                 global $wgWellFormedXml;
 168                 $attribs = (array)$attribs;
 169                 // This is not required in HTML5, but let's do it anyway, for
 170                 // consistency and better compression.
 171                 $element = strtolower( $element );
 172
 173                 // In text/html, initial <html> and <head> tags can be omitted under
 174                 // pretty much any sane circumstances, if they have no attributes.  See:
 175                 // <http://www.whatwg.org/html/syntax.html#optional-tags>
 176                 if ( !$wgWellFormedXml && !$attribs
 177                 && in_array( $element, array( 'html', 'head' ) ) ) {
 178                         return '';
 179                 }
 180
 181                 // Remove invalid input types
 182                 if ( $element == 'input' ) {
 183                         $validTypes = array(
 184                                 'hidden',
 185                                 'text',
 186                                 'password',
 187                                 'checkbox',
 188                                 'radio',
 189                                 'file',
 190                                 'submit',
 191                                 'image',
 192                                 'reset',
 193                                 'button',
 194
 195                                 // HTML input types
 196                                 'datetime',
 197                                 'datetime-local',
 198                                 'date',
 199                                 'month',
 200                                 'time',
 201                                 'week',
 202                                 'number',
 203                                 'range',
 204                                 'email',
 205                                 'url',
 206                                 'search',
 207                                 'tel',
 208                                 'color',
 209                         );
 210                         if ( isset( $attribs['type'] )
 211                         && !in_array( $attribs['type'], $validTypes ) ) {
 212                                 unset( $attribs['type'] );
 213                         }
 214                 }
 215
 216                 // According to standard the default type for <button> elements is "submit".
 217                 // Depending on compatibility mode IE might use "button", instead.
 218                 // We enforce the standard "submit".
 219                 if ( $element == 'button' && !isset( $attribs['type'] ) ) {
 220                         $attribs['type'] = 'submit';
 221                 }
 222
 223                 return "<$element" . self::expandAttributes(
 224                         self::dropDefaults( $element, $attribs ) ) . '>';
 225         }
 226
 227         /**
 228          * Returns "</$element>", except if $wgWellFormedXml is off, in which case
 229          * it returns the empty string when that's guaranteed to be safe.
 230          *
 231          * @since 1.17
 232          * @param string $element Name of the element, e.g., 'a'
 233          * @return string A closing tag, if required
 234          */
 235         public static function closeElement( $element ) {
 236                 $element = strtolower( $element );
 237
 238                 return "</$element>";
 239         }
 240
 241         /**
 242          * Given an element name and an associative array of element attributes,
 243          * return an array that is functionally identical to the input array, but
 244          * possibly smaller.  In particular, attributes might be stripped if they
 245          * are given their default values.
 246          *
 247          * This method is not guaranteed to remove all redundant attributes, only
 248          * some common ones and some others selected arbitrarily at random.  It
 249          * only guarantees that the output array should be functionally identical
 250          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 251          *
 252          * @param string $element Name of the element, e.g., 'a'
 253          * @param array $attribs Associative array of attributes, e.g., array(
 254          *   'href' => 'http://www.mediawiki.org/' ).  See expandAttributes() for
 255          *   further documentation.
 256          * @return array An array of attributes functionally identical to $attribs
 257          */
 258         private static function dropDefaults( $element, $attribs ) {
 259
 260                 // Whenever altering this array, please provide a covering test case
 261                 // in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 262                 static $attribDefaults = array(
 263                         'area' => array( 'shape' => 'rect' ),
 264                         'button' => array(
 265                                 'formaction' => 'GET',
 266                                 'formenctype' => 'application/x-www-form-urlencoded',
 267                         ),
 268                         'canvas' => array(
 269                                 'height' => '150',
 270                                 'width' => '300',
 271                         ),
 272                         'command' => array( 'type' => 'command' ),
 273                         'form' => array(
 274                                 'action' => 'GET',
 275                                 'autocomplete' => 'on',
 276                                 'enctype' => 'application/x-www-form-urlencoded',
 277                         ),
 278                         'input' => array(
 279                                 'formaction' => 'GET',
 280                                 'type' => 'text',
 281                         ),
 282                         'keygen' => array( 'keytype' => 'rsa' ),
 283                         'link' => array( 'media' => 'all' ),
 284                         'menu' => array( 'type' => 'list' ),
 285                         // Note: the use of text/javascript here instead of other JavaScript
 286                         // MIME types follows the HTML5 spec.
 287                         'script' => array( 'type' => 'text/javascript' ),
 288                         'style' => array(
 289                                 'media' => 'all',
 290                                 'type' => 'text/css',
 291                         ),
 292                         'textarea' => array( 'wrap' => 'soft' ),
 293                 );
 294
 295                 $element = strtolower( $element );
 296
 297                 foreach ( $attribs as $attrib => $value ) {
 298                         $lcattrib = strtolower( $attrib );
 299                         if ( is_array( $value ) ) {
 300                                 $value = implode( ' ', $value );
 301                         } else {
 302                                 $value = strval( $value );
 303                         }
 304
 305                         // Simple checks using $attribDefaults
 306                         if ( isset( $attribDefaults[$element][$lcattrib] ) &&
 307                         $attribDefaults[$element][$lcattrib] == $value ) {
 308                                 unset( $attribs[$attrib] );
 309                         }
 310
 311                         if ( $lcattrib == 'class' && $value == '' ) {
 312                                 unset( $attribs[$attrib] );
 313                         }
 314                 }
 315
 316                 // More subtle checks
 317                 if ( $element === 'link' && isset( $attribs['type'] )
 318                 && strval( $attribs['type'] ) == 'text/css' ) {
 319                         unset( $attribs['type'] );
 320                 }
 321                 if ( $element === 'input' ) {
 322                         $type = isset( $attribs['type'] ) ? $attribs['type'] : null;
 323                         $value = isset( $attribs['value'] ) ? $attribs['value'] : null;
 324                         if ( $type === 'checkbox' || $type === 'radio' ) {
 325                                 // The default value for checkboxes and radio buttons is 'on'
 326                                 // not ''. By stripping value="" we break radio boxes that
 327                                 // actually wants empty values.
 328                                 if ( $value === 'on' ) {
 329                                         unset( $attribs['value'] );
 330                                 }
 331                         } elseif ( $type === 'submit' ) {
 332                                 // The default value for submit appears to be "Submit" but
 333                                 // let's not bother stripping out localized text that matches
 334                                 // that.
 335                         } else {
 336                                 // The default value for nearly every other field type is ''
 337                                 // The 'range' and 'color' types use different defaults but
 338                                 // stripping a value="" does not hurt them.
 339                                 if ( $value === '' ) {
 340                                         unset( $attribs['value'] );
 341                                 }
 342                         }
 343                 }
 344                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 345                         if ( in_array( 'multiple', $attribs )
 346                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 347                         ) {
 348                                 // A multi-select
 349                                 if ( strval( $attribs['size'] ) == '4' ) {
 350                                         unset( $attribs['size'] );
 351                                 }
 352                         } else {
 353                                 // Single select
 354                                 if ( strval( $attribs['size'] ) == '1' ) {
 355                                         unset( $attribs['size'] );
 356                                 }
 357                         }
 358                 }
 359
 360                 return $attribs;
 361         }
 362
 363         /**
 364          * Given an associative array of element attributes, generate a string
 365          * to stick after the element name in HTML output.  Like array( 'href' =>
 366          * 'http://www.mediawiki.org/' ) becomes something like
 367          * ' href="http://www.mediawiki.org"'.  Again, this is like
 368          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 369          * For instance, it will omit quotation marks if $wgWellFormedXml is false,
 370          * and will treat boolean attributes specially.
 371          *
 372          * Attributes that can contain space-separated lists ('class', 'accesskey' and 'rel') array
 373          * values are allowed as well, which will automagically be normalized
 374          * and converted to a space-separated string. In addition to a numerical
 375          * array, the attribute value may also be an associative array. See the
 376          * example below for how that works.
 377          *
 378          * @par Numerical array
 379          * @code
 380          *     Html::element( 'em', array(
 381          *         'class' => array( 'foo', 'bar' )
 382          *     ) );
 383          *     // gives '<em class="foo bar"></em>'
 384          * @endcode
 385          *
 386          * @par Associative array
 387          * @code
 388          *     Html::element( 'em', array(
 389          *         'class' => array( 'foo', 'bar', 'foo' => false, 'quux' => true )
 390          *     ) );
 391          *     // gives '<em class="bar quux"></em>'
 392          * @endcode
 393          *
 394          * @param array $attribs Associative array of attributes, e.g., array(
 395          *   'href' => 'http://www.mediawiki.org/' ).  Values will be HTML-escaped.
 396          *   A value of false means to omit the attribute.  For boolean attributes,
 397          *   you can omit the key, e.g., array( 'checked' ) instead of
 398          *   array( 'checked' => 'checked' ) or such.
 399          *
 400          * @throws MWException If an attribute that doesn't allow lists is set to an array
 401          * @return string HTML fragment that goes between element name and '>'
 402          *   (starting with a space if at least one attribute is output)
 403          */
 404         public static function expandAttributes( $attribs ) {
 405                 global $wgWellFormedXml;
 406
 407                 $ret = '';
 408                 $attribs = (array)$attribs;
 409                 foreach ( $attribs as $key => $value ) {
 410                         // Support intuitive array( 'checked' => true/false ) form
 411                         if ( $value === false || is_null( $value ) ) {
 412                                 continue;
 413                         }
 414
 415                         // For boolean attributes, support array( 'foo' ) instead of
 416                         // requiring array( 'foo' => 'meaningless' ).
 417                         if ( is_int( $key )
 418                         && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 419                                 $key = $value;
 420                         }
 421
 422                         // Not technically required in HTML5 but we'd like consistency
 423                         // and better compression anyway.
 424                         $key = strtolower( $key );
 425
 426                         // Bug 23769: Blacklist all form validation attributes for now.  Current
 427                         // (June 2010) WebKit has no UI, so the form just refuses to submit
 428                         // without telling the user why, which is much worse than failing
 429                         // server-side validation.  Opera is the only other implementation at
 430                         // this time, and has ugly UI, so just kill the feature entirely until
 431                         // we have at least one good implementation.
 432
 433                         // As the default value of "1" for "step" rejects decimal
 434                         // numbers to be entered in 'type="number"' fields, allow
 435                         // the special case 'step="any"'.
 436
 437                         if ( in_array( $key, array( 'max', 'min', 'pattern', 'required' ) )
 438                                 || $key === 'step' && $value !== 'any' ) {
 439                                 continue;
 440                         }
 441
 442                         // http://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 443                         // http://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 444                         $spaceSeparatedListAttributes = array(
 445                                 'class', // html4, html5
 446                                 'accesskey', // as of html5, multiple space-separated values allowed
 447                                 // html4-spec doesn't document rel= as space-separated
 448                                 // but has been used like that and is now documented as such
 449                                 // in the html5-spec.
 450                                 'rel',
 451                         );
 452
 453                         // Specific features for attributes that allow a list of space-separated values
 454                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 455                                 // Apply some normalization and remove duplicates
 456
 457                                 // Convert into correct array. Array can contain space-separated
 458                                 // values. Implode/explode to get those into the main array as well.
 459                                 if ( is_array( $value ) ) {
 460                                         // If input wasn't an array, we can skip this step
 461                                         $newValue = array();
 462                                         foreach ( $value as $k => $v ) {
 463                                                 if ( is_string( $v ) ) {
 464                                                         // String values should be normal `array( 'foo' )`
 465                                                         // Just append them
 466                                                         if ( !isset( $value[$v] ) ) {
 467                                                                 // As a special case don't set 'foo' if a
 468                                                                 // separate 'foo' => true/false exists in the array
 469                                                                 // keys should be authoritative
 470                                                                 $newValue[] = $v;
 471                                                         }
 472                                                 } elseif ( $v ) {
 473                                                         // If the value is truthy but not a string this is likely
 474                                                         // an array( 'foo' => true ), falsy values don't add strings
 475                                                         $newValue[] = $k;
 476                                                 }
 477                                         }
 478                                         $value = implode( ' ', $newValue );
 479                                 }
 480                                 $value = explode( ' ', $value );
 481
 482                                 // Normalize spacing by fixing up cases where people used
 483                                 // more than 1 space and/or a trailing/leading space
 484                                 $value = array_diff( $value, array( '', ' ' ) );
 485
 486                                 // Remove duplicates and create the string
 487                                 $value = implode( ' ', array_unique( $value ) );
 488                         } elseif ( is_array( $value ) ) {
 489                                 throw new MWException( "HTML attribute $key can not contain a list of values" );
 490                         }
 491
 492                         // See the "Attributes" section in the HTML syntax part of HTML5,
 493                         // 9.1.2.3 as of 2009-08-10.  Most attributes can have quotation
 494                         // marks omitted, but not all.  (Although a literal " is not
 495                         // permitted, we don't check for that, since it will be escaped
 496                         // anyway.)
 497                         #
 498                         // See also research done on further characters that need to be
 499                         // escaped: http://code.google.com/p/html5lib/issues/detail?id=93
 500                         $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}"
 501                                 . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}"
 502                                 . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}";
 503                         if ( $wgWellFormedXml || $value === ''
 504                         || preg_match( "![$badChars]!u", $value ) ) {
 505                                 $quote = '"';
 506                         } else {
 507                                 $quote = '';
 508                         }
 509
 510                         if ( in_array( $key, self::$boolAttribs ) ) {
 511                                 // In HTML5, we can leave the value empty. If we don't need
 512                                 // well-formed XML, we can omit the = entirely.
 513                                 if ( !$wgWellFormedXml ) {
 514                                         $ret .= " $key";
 515                                 } else {
 516                                         $ret .= " $key=\"\"";
 517                                 }
 518                         } else {
 519                                 // Apparently we need to entity-encode \n, \r, \t, although the
 520                                 // spec doesn't mention that.  Since we're doing strtr() anyway,
 521                                 // and we don't need <> escaped here, we may as well not call
 522                                 // htmlspecialchars().
 523                                 // @todo FIXME: Verify that we actually need to
 524                                 // escape \n\r\t here, and explain why, exactly.
 525                                 #
 526                                 // We could call Sanitizer::encodeAttribute() for this, but we
 527                                 // don't because we're stubborn and like our marginal savings on
 528                                 // byte size from not having to encode unnecessary quotes.
 529                                 $map = array(
 530                                         '&' => '&amp;',
 531                                         '"' => '&quot;',
 532                                         "\n" => '&#10;',
 533                                         "\r" => '&#13;',
 534                                         "\t" => '&#9;'
 535                                 );
 536                                 if ( $wgWellFormedXml ) {
 537                                         // This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue>
 538                                         // But reportedly it breaks some XML tools?
 539                                         // @todo FIXME: Is this really true?
 540                                         $map['<'] = '&lt;';
 541                                 }
 542                                 $ret .= " $key=$quote" . strtr( $value, $map ) . $quote;
 543                         }
 544                 }
 545                 return $ret;
 546         }
 547
 548         /**
 549          * Output a "<script>" tag with the given contents.
 550          *
 551          * @todo do some useful escaping as well, like if $contents contains
 552          * literal "</script>" or (for XML) literal "]]>".
 553          *
 554          * @param string $contents JavaScript
 555          * @return string Raw HTML
 556          */
 557         public static function inlineScript( $contents ) {
 558                 global $wgWellFormedXml;
 559
 560                 $attrs = array();
 561
 562                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 563                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 564                 }
 565
 566                 return self::rawElement( 'script', $attrs, $contents );
 567         }
 568
 569         /**
 570          * Output a "<script>" tag linking to the given URL, e.g.,
 571          * "<script src=foo.js></script>".
 572          *
 573          * @param string $url
 574          * @return string Raw HTML
 575          */
 576         public static function linkedScript( $url ) {
 577                 $attrs = array( 'src' => $url );
 578
 579                 return self::element( 'script', $attrs );
 580         }
 581
 582         /**
 583          * Output a "<style>" tag with the given contents for the given media type
 584          * (if any).  TODO: do some useful escaping as well, like if $contents
 585          * contains literal "</style>" (admittedly unlikely).
 586          *
 587          * @param string $contents CSS
 588          * @param string $media A media type string, like 'screen'
 589          * @return string Raw HTML
 590          */
 591         public static function inlineStyle( $contents, $media = 'all' ) {
 592                 global $wgWellFormedXml;
 593
 594                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 595                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 596                 }
 597
 598                 return self::rawElement( 'style', array(
 599                         'type' => 'text/css',
 600                         'media' => $media,
 601                 ), $contents );
 602         }
 603
 604         /**
 605          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 606          * media type (if any).
 607          *
 608          * @param string $url
 609          * @param string $media A media type string, like 'screen'
 610          * @return string Raw HTML
 611          */
 612         public static function linkedStyle( $url, $media = 'all' ) {
 613                 return self::element( 'link', array(
 614                         'rel' => 'stylesheet',
 615                         'href' => $url,
 616                         'type' => 'text/css',
 617                         'media' => $media,
 618                 ) );
 619         }
 620
 621         /**
 622          * Convenience function to produce an "<input>" element.  This supports the
 623          * new HTML5 input types and attributes.
 624          *
 625          * @param string $name Name attribute
 626          * @param array $value Value attribute
 627          * @param string $type Type attribute
 628          * @param array $attribs Associative array of miscellaneous extra
 629          *   attributes, passed to Html::element()
 630          * @return string Raw HTML
 631          */
 632         public static function input( $name, $value = '', $type = 'text', $attribs = array() ) {
 633                 $attribs['type'] = $type;
 634                 $attribs['value'] = $value;
 635                 $attribs['name'] = $name;
 636
 637                 return self::element( 'input', $attribs );
 638         }
 639
 640         /**
 641          * Convenience function to produce a checkbox (input element with type=checkbox)
 642          *
 643          * @param string $name Name attribute
 644          * @param bool $checked Whether the checkbox is checked or not
 645          * @param array $attribs Array of additional attributes
 646          */
 647         public static function check( $name, $checked = false, array $attribs = array() ) {
 648                 if ( isset( $attribs['value'] ) ) {
 649                         $value = $attribs['value'];
 650                         unset( $attribs['value'] );
 651                 } else {
 652                         $value = 1;
 653                 }
 654
 655                 if ( $checked ) {
 656                         $attribs[] = 'checked';
 657                 }
 658
 659                 return self::input( $name, $value, 'checkbox', $attribs );
 660         }
 661
 662         /**
 663          * Convenience function to produce a checkbox (input element with type=checkbox)
 664          *
 665          * @param string $name Name attribute
 666          * @param bool $checked Whether the checkbox is checked or not
 667          * @param array $attribs Array of additional attributes
 668          */
 669         public static function radio( $name, $checked = false, array $attribs = array() ) {
 670                 if ( isset( $attribs['value'] ) ) {
 671                         $value = $attribs['value'];
 672                         unset( $attribs['value'] );
 673                 } else {
 674                         $value = 1;
 675                 }
 676
 677                 if ( $checked ) {
 678                         $attribs[] = 'checked';
 679                 }
 680
 681                 return self::input( $name, $value, 'radio', $attribs );
 682         }
 683
 684         /**
 685          * Convenience function for generating a label for inputs.
 686          *
 687          * @param string $label Contents of the label
 688          * @param string $id ID of the element being labeled
 689          * @param array $attribs Additional attributes
 690          */
 691         public static function label( $label, $id, array $attribs = array() ) {
 692                 $attribs += array(
 693                         'for' => $id
 694                 );
 695                 return self::element( 'label', $attribs, $label );
 696         }
 697
 698         /**
 699          * Convenience function to produce an input element with type=hidden
 700          *
 701          * @param string $name Name attribute
 702          * @param string $value Value attribute
 703          * @param array $attribs Associative array of miscellaneous extra
 704          *   attributes, passed to Html::element()
 705          * @return string Raw HTML
 706          */
 707         public static function hidden( $name, $value, $attribs = array() ) {
 708                 return self::input( $name, $value, 'hidden', $attribs );
 709         }
 710
 711         /**
 712          * Convenience function to produce a <textarea> element.
 713          *
 714          * This supports leaving out the cols= and rows= which Xml requires and are
 715          * required by HTML4/XHTML but not required by HTML5.
 716          *
 717          * @param string $name Name attribute
 718          * @param string $value Value attribute
 719          * @param array $attribs Associative array of miscellaneous extra
 720          *   attributes, passed to Html::element()
 721          * @return string Raw HTML
 722          */
 723         public static function textarea( $name, $value = '', $attribs = array() ) {
 724                 $attribs['name'] = $name;
 725
 726                 if ( substr( $value, 0, 1 ) == "\n" ) {
 727                         // Workaround for bug 12130: browsers eat the initial newline
 728                         // assuming that it's just for show, but they do keep the later
 729                         // newlines, which we may want to preserve during editing.
 730                         // Prepending a single newline
 731                         $spacedValue = "\n" . $value;
 732                 } else {
 733                         $spacedValue = $value;
 734                 }
 735                 return self::element( 'textarea', $attribs, $spacedValue );
 736         }
 737
 738         /**
 739          * Build a drop-down box for selecting a namespace
 740          *
 741          * @param array $params Params to set.
 742          * - selected: [optional] Id of namespace which should be pre-selected
 743          * - all: [optional] Value of item for "all namespaces". If null or unset,
 744          *   no "<option>" is generated to select all namespaces.
 745          * - label: text for label to add before the field.
 746          * - exclude: [optional] Array of namespace ids to exclude.
 747          * - disable: [optional] Array of namespace ids for which the option should
 748          *   be disabled in the selector.
 749          * @param array $selectAttribs 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(),
 755                 array $selectAttribs = array()
 756         ) {
 757                 global $wgContLang;
 758
 759                 ksort( $selectAttribs );
 760
 761                 // Is a namespace selected?
 762                 if ( isset( $params['selected'] ) ) {
 763                         // If string only contains digits, convert to clean int. Selected could also
 764                         // be "all" or "" etc. which needs to be left untouched.
 765                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 766                         // and returns false for already clean ints. Use regex instead..
 767                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 768                                 $params['selected'] = intval( $params['selected'] );
 769                         }
 770                         // else: leaves it untouched for later processing
 771                 } else {
 772                         $params['selected'] = '';
 773                 }
 774
 775                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 776                         $params['exclude'] = array();
 777                 }
 778                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 779                         $params['disable'] = array();
 780                 }
 781
 782                 // Associative array between option-values and option-labels
 783                 $options = array();
 784
 785                 if ( isset( $params['all'] ) ) {
 786                         // add an option that would let the user select all namespaces.
 787                         // Value is provided by user, the name shown is localized for the user.
 788                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 789                 }
 790                 // Add all namespaces as options (in the content language)
 791                 $options += $wgContLang->getFormattedNamespaces();
 792
 793                 // Convert $options to HTML and filter out namespaces below 0
 794                 $optionsHtml = array();
 795                 foreach ( $options as $nsId => $nsName ) {
 796                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 797                                 continue;
 798                         }
 799                         if ( $nsId === NS_MAIN ) {
 800                                 // For other namespaces use use the namespace prefix as label, but for
 801                                 // main we don't use "" but the user message describing it (e.g. "(Main)" or "(Article)")
 802                                 $nsName = wfMessage( 'blanknamespace' )->text();
 803                         } elseif ( is_int( $nsId ) ) {
 804                                 $nsName = $wgContLang->convertNamespace( $nsId );
 805                         }
 806                         $optionsHtml[] = Html::element(
 807                                 'option', array(
 808                                         'disabled' => in_array( $nsId, $params['disable'] ),
 809                                         'value' => $nsId,
 810                                         'selected' => $nsId === $params['selected'],
 811                                 ), $nsName
 812                         );
 813                 }
 814
 815                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 816                         $selectAttribs['id'] = 'namespace';
 817                 }
 818
 819                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 820                         $selectAttribs['name'] = 'namespace';
 821                 }
 822
 823                 $ret = '';
 824                 if ( isset( $params['label'] ) ) {
 825                         $ret .= Html::element(
 826                                 'label', array(
 827                                         'for' => isset( $selectAttribs['id'] ) ? $selectAttribs['id'] : null,
 828                                 ), $params['label']
 829                         ) . '&#160;';
 830                 }
 831
 832                 // Wrap options in a <select>
 833                 $ret .= Html::openElement( 'select', $selectAttribs )
 834                         . "\n"
 835                         . implode( "\n", $optionsHtml )
 836                         . "\n"
 837                         . Html::closeElement( 'select' );
 838
 839                 return $ret;
 840         }
 841
 842         /**
 843          * Constructs the opening html-tag with necessary doctypes depending on
 844          * global variables.
 845          *
 846          * @param array $attribs Associative array of miscellaneous extra
 847          *   attributes, passed to Html::element() of html tag.
 848          * @return string Raw HTML
 849          */
 850         public static function htmlHeader( $attribs = array() ) {
 851                 $ret = '';
 852
 853                 global $wgHtml5Version, $wgMimeType, $wgXhtmlNamespaces;
 854
 855                 $isXHTML = self::isXmlMimeType( $wgMimeType );
 856
 857                 if ( $isXHTML ) { // XHTML5
 858                         // XML MIME-typed markup should have an xml header.
 859                         // However a DOCTYPE is not needed.
 860                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 861
 862                         // Add the standard xmlns
 863                         $attribs['xmlns'] = 'http://www.w3.org/1999/xhtml';
 864
 865                         // And support custom namespaces
 866                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 867                                 $attribs["xmlns:$tag"] = $ns;
 868                         }
 869                 } else { // HTML5
 870                         // DOCTYPE
 871                         $ret .= "<!DOCTYPE html>\n";
 872                 }
 873
 874                 if ( $wgHtml5Version ) {
 875                         $attribs['version'] = $wgHtml5Version;
 876                 }
 877
 878                 $html = Html::openElement( 'html', $attribs );
 879
 880                 if ( $html ) {
 881                         $html .= "\n";
 882                 }
 883
 884                 $ret .= $html;
 885
 886                 return $ret;
 887         }
 888
 889         /**
 890          * Determines if the given MIME type is xml.
 891          *
 892          * @param string $mimetype MIME type
 893          * @return bool
 894          */
 895         public static function isXmlMimeType( $mimetype ) {
 896                 # http://www.whatwg.org/html/infrastructure.html#xml-mime-type
 897                 # * text/xml
 898                 # * application/xml
 899                 # * Any MIME type with a subtype ending in +xml (this implicitly includes application/xhtml+xml)
 900                 return (bool)preg_match( '!^(text|application)/xml$|^.+/.+\+xml$!', $mimetype );
 901         }
 902
 903         /**
 904          * Get HTML for an info box with an icon.
 905          *
 906          * @param string $text Wikitext, get this with wfMessage()->plain()
 907          * @param string $icon Icon name, file in skins/common/images
 908          * @param string $alt Alternate text for the icon
 909          * @param string $class Additional class name to add to the wrapper div
 910          * @param bool $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/html/embedded-content-1.html#attr-img-srcset
 957                         $candidates[] = "{$url} {$density}x";
 958                 }
 959                 return implode( ", ", $candidates );
 960         }
 961 }