includes/Html.php

   1 <?php
   2 /**
   3  * Collection of methods to generate HTML content
   4  *
   5  * Copyright © 2009 Aryeh Gregor
   6  * http://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  */
  25
  26 /**
  27  * This class is a collection of static functions that serve two purposes:
  28  *
  29  * 1) Implement any algorithms specified by HTML5, or other HTML
  30  * specifications, in a convenient and self-contained way.
  31  *
  32  * 2) Allow HTML elements to be conveniently and safely generated, like the
  33  * current Xml class but a) less confused (Xml supports HTML-specific things,
  34  * but only sometimes!) and b) not necessarily confined to XML-compatible
  35  * output.
  36  *
  37  * There are two important configuration options this class uses:
  38  *
  39  * $wgMimeType: If this is set to an xml MIME type then output should be
  40  *     valid XHTML5.
  41  * $wgWellFormedXml: If this is set to true, then all output should be
  42  *     well-formed XML (quotes on attributes, self-closing tags, etc.).
  43  *
  44  * This class is meant to be confined to utility functions that are called from
  45  * trusted code paths.  It does not do enforcement of policy like not allowing
  46  * <a> elements.
  47  *
  48  * @since 1.16
  49  */
  50 class Html {
  51         // List of void elements from HTML5, section 8.1.2 as of 2011-08-12
  52         private static $voidElements = array(
  53                 'area',
  54                 'base',
  55                 'br',
  56                 'col',
  57                 'command',
  58                 'embed',
  59                 'hr',
  60                 'img',
  61                 'input',
  62                 'keygen',
  63                 'link',
  64                 'meta',
  65                 'param',
  66                 'source',
  67                 'track',
  68                 'wbr',
  69         );
  70
  71         // Boolean attributes, which may have the value omitted entirely.  Manually
  72         // collected from the HTML5 spec as of 2011-08-12.
  73         private static $boolAttribs = array(
  74                 'async',
  75                 'autofocus',
  76                 'autoplay',
  77                 'checked',
  78                 'controls',
  79                 'default',
  80                 'defer',
  81                 'disabled',
  82                 'formnovalidate',
  83                 'hidden',
  84                 'ismap',
  85                 'itemscope',
  86                 'loop',
  87                 'multiple',
  88                 'muted',
  89                 'novalidate',
  90                 'open',
  91                 'pubdate',
  92                 'readonly',
  93                 'required',
  94                 'reversed',
  95                 'scoped',
  96                 'seamless',
  97                 'selected',
  98                 'truespeed',
  99                 'typemustmatch',
 100                 // HTML5 Microdata
 101                 'itemscope',
 102         );
 103
 104         /**
 105          * Modifies a set of attributes meant for button elements
 106          * and apply a set of default attributes when $wgUseMediaWikiUIEverywhere enabled.
 107          * @param array $modifiers to add to the button
 108          * @see https://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 109          * @return array $attrs A modified attribute array
 110          */
 111         public static function buttonAttributes( $attrs, $modifiers = array() ) {
 112                 global $wgUseMediaWikiUIEverywhere;
 113                 if ( $wgUseMediaWikiUIEverywhere ) {
 114                         if ( isset( $attrs['class'] ) ) {
 115                                 if ( is_array( $attrs['class'] ) ) {
 116                                         $attrs['class'][] = 'mw-ui-button';
 117                                         $attrs = array_merge( $attrs, $modifiers );
 118                                         // ensure compatibility with Xml
 119                                         $attrs['class'] = implode( ' ', $attrs['class'] );
 120                                 } else {
 121                                         $attrs['class'] .= ' mw-ui-button ' . implode( ' ', $modifiers );
 122                                 }
 123                         } else {
 124                                 $attrs['class'] = array( 'mw-ui-button' );
 125                                 // ensure compatibility with Xml
 126                                 $attrs['class'] = implode( ' ', array_merge( $attrs['class'], $modifiers ) );
 127                         }
 128                 }
 129                 return $attrs;
 130         }
 131
 132         /**
 133          * Modifies a set of attributes meant for text input elements
 134          * and apply a set of default attributes.
 135          * Removes size attribute when $wgUseMediaWikiUIEverywhere enabled.
 136          * @param array $attrs An attribute array.
 137          * @return array $attrs A modified attribute array
 138          */
 139         public static function getTextInputAttributes( $attrs ) {
 140                 global $wgUseMediaWikiUIEverywhere;
 141                 if ( !$attrs ) {
 142                         $attrs = array();
 143                 }
 144                 if ( isset( $attrs['class'] ) ) {
 145                         if ( is_array( $attrs['class'] ) ) {
 146                                 $attrs['class'][] = 'mw-ui-input';
 147                         } else {
 148                                 $attrs['class'] .= ' mw-ui-input';
 149                         }
 150                 } else {
 151                         $attrs['class'] = 'mw-ui-input';
 152                 }
 153                 if ( $wgUseMediaWikiUIEverywhere ) {
 154                         // Note that size can effect the desired width rendering of mw-ui-input elements
 155                         // so it is removed. Left intact when mediawiki ui not enabled.
 156                         unset( $attrs['size'] );
 157                 }
 158                 return $attrs;
 159         }
 160
 161         /**
 162          * Returns an HTML link element in a string styled as a button (when $wgUseMediaWikiUIEverywhere is enabled).
 163          *
 164          * @param string $contents The raw HTML contents of the element: *not*
 165          *   escaped!
 166          * @param array $attrs Associative array of attributes, e.g., array(
 167          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 168          *   further documentation.
 169          * @param array $modifiers to add to the button
 170          * @see http://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 171          * @return string Raw HTML
 172          */
 173         public static function linkButton( $contents, $attrs, $modifiers = array() ) {
 174                 return Html::element( 'a',
 175                         self::buttonAttributes( $attrs, $modifiers ),
 176                         $contents
 177                 );
 178         }
 179
 180         /**
 181          * Returns an HTML link element in a string styled as a button (when $wgUseMediaWikiUIEverywhere is enabled).
 182          *
 183          * @param string $contents The raw HTML contents of the element: *not*
 184          *   escaped!
 185          * @param array $attrs Associative array of attributes, e.g., array(
 186          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 187          *   further documentation.
 188          * @param array $modifiers to add to the button
 189          * @see http://tools.wmflabs.org/styleguide/desktop/index.html for guidance on available modifiers
 190          * @return string Raw HTML
 191          */
 192         public static function submitButton( $contents, $attrs, $modifiers = array() ) {
 193                 $attrs['type'] = 'submit';
 194                 $attrs['value'] = $contents;
 195                 return Html::element( 'input', self::buttonAttributes( $attrs, $modifiers ) );
 196         }
 197
 198         /**
 199          * Returns an HTML element in a string.  The major advantage here over
 200          * manually typing out the HTML is that it will escape all attribute
 201          * values.
 202          *
 203          * This is quite similar to Xml::tags(), but it implements some useful
 204          * HTML-specific logic.  For instance, there is no $allowShortTag
 205          * parameter: the closing tag is magically omitted if $element has an empty
 206          * content model.  If $wgWellFormedXml is false, then a few bytes will be
 207          * shaved off the HTML output as well.
 208          *
 209          * @param string $element The element's name, e.g., 'a'
 210          * @param array $attribs Associative array of attributes, e.g., array(
 211          *   'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for
 212          *   further documentation.
 213          * @param string $contents The raw HTML contents of the element: *not*
 214          *   escaped!
 215          * @return string Raw HTML
 216          */
 217         public static function rawElement( $element, $attribs = array(), $contents = '' ) {
 218                 global $wgWellFormedXml;
 219                 $start = self::openElement( $element, $attribs );
 220                 if ( in_array( $element, self::$voidElements ) ) {
 221                         if ( $wgWellFormedXml ) {
 222                                 // Silly XML.
 223                                 return substr( $start, 0, -1 ) . ' />';
 224                         }
 225                         return $start;
 226                 } else {
 227                         return "$start$contents" . self::closeElement( $element );
 228                 }
 229         }
 230
 231         /**
 232          * Identical to rawElement(), but HTML-escapes $contents (like
 233          * Xml::element()).
 234          *
 235          * @param string $element
 236          * @param array $attribs
 237          * @param string $contents
 238          *
 239          * @return string
 240          */
 241         public static function element( $element, $attribs = array(), $contents = '' ) {
 242                 return self::rawElement( $element, $attribs, strtr( $contents, array(
 243                         // There's no point in escaping quotes, >, etc. in the contents of
 244                         // elements.
 245                         '&' => '&amp;',
 246                         '<' => '&lt;'
 247                 ) ) );
 248         }
 249
 250         /**
 251          * Identical to rawElement(), but has no third parameter and omits the end
 252          * tag (and the self-closing '/' in XML mode for empty elements).
 253          *
 254          * @param string $element
 255          * @param array $attribs
 256          *
 257          * @return string
 258          */
 259         public static function openElement( $element, $attribs = array() ) {
 260                 global $wgWellFormedXml;
 261                 $attribs = (array)$attribs;
 262                 // This is not required in HTML5, but let's do it anyway, for
 263                 // consistency and better compression.
 264                 $element = strtolower( $element );
 265
 266                 // In text/html, initial <html> and <head> tags can be omitted under
 267                 // pretty much any sane circumstances, if they have no attributes.  See:
 268                 // <http://www.whatwg.org/html/syntax.html#optional-tags>
 269                 if ( !$wgWellFormedXml && !$attribs && in_array( $element, array( 'html', 'head' ) ) ) {
 270                         return '';
 271                 }
 272
 273                 // Remove invalid input types
 274                 if ( $element == 'input' ) {
 275                         $validTypes = array(
 276                                 'hidden',
 277                                 'text',
 278                                 'password',
 279                                 'checkbox',
 280                                 'radio',
 281                                 'file',
 282                                 'submit',
 283                                 'image',
 284                                 'reset',
 285                                 'button',
 286
 287                                 // HTML input types
 288                                 'datetime',
 289                                 'datetime-local',
 290                                 'date',
 291                                 'month',
 292                                 'time',
 293                                 'week',
 294                                 'number',
 295                                 'range',
 296                                 'email',
 297                                 'url',
 298                                 'search',
 299                                 'tel',
 300                                 'color',
 301                         );
 302                         if ( isset( $attribs['type'] ) && !in_array( $attribs['type'], $validTypes ) ) {
 303                                 unset( $attribs['type'] );
 304                         }
 305                 }
 306
 307                 // According to standard the default type for <button> elements is "submit".
 308                 // Depending on compatibility mode IE might use "button", instead.
 309                 // We enforce the standard "submit".
 310                 if ( $element == 'button' && !isset( $attribs['type'] ) ) {
 311                         $attribs['type'] = 'submit';
 312                 }
 313
 314                 return "<$element" . self::expandAttributes(
 315                         self::dropDefaults( $element, $attribs ) ) . '>';
 316         }
 317
 318         /**
 319          * Returns "</$element>"
 320          *
 321          * @since 1.17
 322          * @param string $element Name of the element, e.g., 'a'
 323          * @return string A closing tag
 324          */
 325         public static function closeElement( $element ) {
 326                 $element = strtolower( $element );
 327
 328                 return "</$element>";
 329         }
 330
 331         /**
 332          * Given an element name and an associative array of element attributes,
 333          * return an array that is functionally identical to the input array, but
 334          * possibly smaller.  In particular, attributes might be stripped if they
 335          * are given their default values.
 336          *
 337          * This method is not guaranteed to remove all redundant attributes, only
 338          * some common ones and some others selected arbitrarily at random.  It
 339          * only guarantees that the output array should be functionally identical
 340          * to the input array (currently per the HTML 5 draft as of 2009-09-06).
 341          *
 342          * @param string $element Name of the element, e.g., 'a'
 343          * @param array $attribs Associative array of attributes, e.g., array(
 344          *   'href' => 'http://www.mediawiki.org/' ).  See expandAttributes() for
 345          *   further documentation.
 346          * @return array An array of attributes functionally identical to $attribs
 347          */
 348         private static function dropDefaults( $element, $attribs ) {
 349
 350                 // Whenever altering this array, please provide a covering test case
 351                 // in HtmlTest::provideElementsWithAttributesHavingDefaultValues
 352                 static $attribDefaults = array(
 353                         'area' => array( 'shape' => 'rect' ),
 354                         'button' => array(
 355                                 'formaction' => 'GET',
 356                                 'formenctype' => 'application/x-www-form-urlencoded',
 357                         ),
 358                         'canvas' => array(
 359                                 'height' => '150',
 360                                 'width' => '300',
 361                         ),
 362                         'command' => array( 'type' => 'command' ),
 363                         'form' => array(
 364                                 'action' => 'GET',
 365                                 'autocomplete' => 'on',
 366                                 'enctype' => 'application/x-www-form-urlencoded',
 367                         ),
 368                         'input' => array(
 369                                 'formaction' => 'GET',
 370                                 'type' => 'text',
 371                         ),
 372                         'keygen' => array( 'keytype' => 'rsa' ),
 373                         'link' => array( 'media' => 'all' ),
 374                         'menu' => array( 'type' => 'list' ),
 375                         // Note: the use of text/javascript here instead of other JavaScript
 376                         // MIME types follows the HTML5 spec.
 377                         'script' => array( 'type' => 'text/javascript' ),
 378                         'style' => array(
 379                                 'media' => 'all',
 380                                 'type' => 'text/css',
 381                         ),
 382                         'textarea' => array( 'wrap' => 'soft' ),
 383                 );
 384
 385                 $element = strtolower( $element );
 386
 387                 foreach ( $attribs as $attrib => $value ) {
 388                         $lcattrib = strtolower( $attrib );
 389                         if ( is_array( $value ) ) {
 390                                 $value = implode( ' ', $value );
 391                         } else {
 392                                 $value = strval( $value );
 393                         }
 394
 395                         // Simple checks using $attribDefaults
 396                         if ( isset( $attribDefaults[$element][$lcattrib] )
 397                                 && $attribDefaults[$element][$lcattrib] == $value
 398                         ) {
 399                                 unset( $attribs[$attrib] );
 400                         }
 401
 402                         if ( $lcattrib == 'class' && $value == '' ) {
 403                                 unset( $attribs[$attrib] );
 404                         }
 405                 }
 406
 407                 // More subtle checks
 408                 if ( $element === 'link'
 409                         && isset( $attribs['type'] ) && strval( $attribs['type'] ) == 'text/css'
 410                 ) {
 411                         unset( $attribs['type'] );
 412                 }
 413                 if ( $element === 'input' ) {
 414                         $type = isset( $attribs['type'] ) ? $attribs['type'] : null;
 415                         $value = isset( $attribs['value'] ) ? $attribs['value'] : null;
 416                         if ( $type === 'checkbox' || $type === 'radio' ) {
 417                                 // The default value for checkboxes and radio buttons is 'on'
 418                                 // not ''. By stripping value="" we break radio boxes that
 419                                 // actually wants empty values.
 420                                 if ( $value === 'on' ) {
 421                                         unset( $attribs['value'] );
 422                                 }
 423                         } elseif ( $type === 'submit' ) {
 424                                 // The default value for submit appears to be "Submit" but
 425                                 // let's not bother stripping out localized text that matches
 426                                 // that.
 427                         } else {
 428                                 // The default value for nearly every other field type is ''
 429                                 // The 'range' and 'color' types use different defaults but
 430                                 // stripping a value="" does not hurt them.
 431                                 if ( $value === '' ) {
 432                                         unset( $attribs['value'] );
 433                                 }
 434                         }
 435                 }
 436                 if ( $element === 'select' && isset( $attribs['size'] ) ) {
 437                         if ( in_array( 'multiple', $attribs )
 438                                 || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false )
 439                         ) {
 440                                 // A multi-select
 441                                 if ( strval( $attribs['size'] ) == '4' ) {
 442                                         unset( $attribs['size'] );
 443                                 }
 444                         } else {
 445                                 // Single select
 446                                 if ( strval( $attribs['size'] ) == '1' ) {
 447                                         unset( $attribs['size'] );
 448                                 }
 449                         }
 450                 }
 451
 452                 return $attribs;
 453         }
 454
 455         /**
 456          * Given an associative array of element attributes, generate a string
 457          * to stick after the element name in HTML output.  Like array( 'href' =>
 458          * 'http://www.mediawiki.org/' ) becomes something like
 459          * ' href="http://www.mediawiki.org"'.  Again, this is like
 460          * Xml::expandAttributes(), but it implements some HTML-specific logic.
 461          * For instance, it will omit quotation marks if $wgWellFormedXml is false,
 462          * and will treat boolean attributes specially.
 463          *
 464          * Attributes that can contain space-separated lists ('class', 'accesskey' and 'rel') array
 465          * values are allowed as well, which will automagically be normalized
 466          * and converted to a space-separated string. In addition to a numerical
 467          * array, the attribute value may also be an associative array. See the
 468          * example below for how that works.
 469          *
 470          * @par Numerical array
 471          * @code
 472          *     Html::element( 'em', array(
 473          *         'class' => array( 'foo', 'bar' )
 474          *     ) );
 475          *     // gives '<em class="foo bar"></em>'
 476          * @endcode
 477          *
 478          * @par Associative array
 479          * @code
 480          *     Html::element( 'em', array(
 481          *         'class' => array( 'foo', 'bar', 'foo' => false, 'quux' => true )
 482          *     ) );
 483          *     // gives '<em class="bar quux"></em>'
 484          * @endcode
 485          *
 486          * @param array $attribs Associative array of attributes, e.g., array(
 487          *   'href' => 'http://www.mediawiki.org/' ).  Values will be HTML-escaped.
 488          *   A value of false means to omit the attribute.  For boolean attributes,
 489          *   you can omit the key, e.g., array( 'checked' ) instead of
 490          *   array( 'checked' => 'checked' ) or such.
 491          *
 492          * @throws MWException If an attribute that doesn't allow lists is set to an array
 493          * @return string HTML fragment that goes between element name and '>'
 494          *   (starting with a space if at least one attribute is output)
 495          */
 496         public static function expandAttributes( $attribs ) {
 497                 global $wgWellFormedXml;
 498
 499                 $ret = '';
 500                 $attribs = (array)$attribs;
 501                 foreach ( $attribs as $key => $value ) {
 502                         // Support intuitive array( 'checked' => true/false ) form
 503                         if ( $value === false || is_null( $value ) ) {
 504                                 continue;
 505                         }
 506
 507                         // For boolean attributes, support array( 'foo' ) instead of
 508                         // requiring array( 'foo' => 'meaningless' ).
 509                         if ( is_int( $key ) && in_array( strtolower( $value ), self::$boolAttribs ) ) {
 510                                 $key = $value;
 511                         }
 512
 513                         // Not technically required in HTML5 but we'd like consistency
 514                         // and better compression anyway.
 515                         $key = strtolower( $key );
 516
 517                         // Bug 23769: Blacklist all form validation attributes for now.  Current
 518                         // (June 2010) WebKit has no UI, so the form just refuses to submit
 519                         // without telling the user why, which is much worse than failing
 520                         // server-side validation.  Opera is the only other implementation at
 521                         // this time, and has ugly UI, so just kill the feature entirely until
 522                         // we have at least one good implementation.
 523
 524                         // As the default value of "1" for "step" rejects decimal
 525                         // numbers to be entered in 'type="number"' fields, allow
 526                         // the special case 'step="any"'.
 527
 528                         if ( in_array( $key, array( 'max', 'min', 'pattern', 'required' ) )
 529                                 || $key === 'step' && $value !== 'any' ) {
 530                                 continue;
 531                         }
 532
 533                         // http://www.w3.org/TR/html401/index/attributes.html ("space-separated")
 534                         // http://www.w3.org/TR/html5/index.html#attributes-1 ("space-separated")
 535                         $spaceSeparatedListAttributes = array(
 536                                 'class', // html4, html5
 537                                 'accesskey', // as of html5, multiple space-separated values allowed
 538                                 // html4-spec doesn't document rel= as space-separated
 539                                 // but has been used like that and is now documented as such
 540                                 // in the html5-spec.
 541                                 'rel',
 542                         );
 543
 544                         // Specific features for attributes that allow a list of space-separated values
 545                         if ( in_array( $key, $spaceSeparatedListAttributes ) ) {
 546                                 // Apply some normalization and remove duplicates
 547
 548                                 // Convert into correct array. Array can contain space-separated
 549                                 // values. Implode/explode to get those into the main array as well.
 550                                 if ( is_array( $value ) ) {
 551                                         // If input wasn't an array, we can skip this step
 552                                         $newValue = array();
 553                                         foreach ( $value as $k => $v ) {
 554                                                 if ( is_string( $v ) ) {
 555                                                         // String values should be normal `array( 'foo' )`
 556                                                         // Just append them
 557                                                         if ( !isset( $value[$v] ) ) {
 558                                                                 // As a special case don't set 'foo' if a
 559                                                                 // separate 'foo' => true/false exists in the array
 560                                                                 // keys should be authoritative
 561                                                                 $newValue[] = $v;
 562                                                         }
 563                                                 } elseif ( $v ) {
 564                                                         // If the value is truthy but not a string this is likely
 565                                                         // an array( 'foo' => true ), falsy values don't add strings
 566                                                         $newValue[] = $k;
 567                                                 }
 568                                         }
 569                                         $value = implode( ' ', $newValue );
 570                                 }
 571                                 $value = explode( ' ', $value );
 572
 573                                 // Normalize spacing by fixing up cases where people used
 574                                 // more than 1 space and/or a trailing/leading space
 575                                 $value = array_diff( $value, array( '', ' ' ) );
 576
 577                                 // Remove duplicates and create the string
 578                                 $value = implode( ' ', array_unique( $value ) );
 579                         } elseif ( is_array( $value ) ) {
 580                                 throw new MWException( "HTML attribute $key can not contain a list of values" );
 581                         }
 582
 583                         // See the "Attributes" section in the HTML syntax part of HTML5,
 584                         // 9.1.2.3 as of 2009-08-10.  Most attributes can have quotation
 585                         // marks omitted, but not all.  (Although a literal " is not
 586                         // permitted, we don't check for that, since it will be escaped
 587                         // anyway.)
 588
 589                         // See also research done on further characters that need to be
 590                         // escaped: http://code.google.com/p/html5lib/issues/detail?id=93
 591                         $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}"
 592                                 . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}"
 593                                 . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}";
 594                         if ( $wgWellFormedXml || $value === '' || preg_match( "![$badChars]!u", $value ) ) {
 595                                 $quote = '"';
 596                         } else {
 597                                 $quote = '';
 598                         }
 599
 600                         if ( in_array( $key, self::$boolAttribs ) ) {
 601                                 // In HTML5, we can leave the value empty. If we don't need
 602                                 // well-formed XML, we can omit the = entirely.
 603                                 if ( !$wgWellFormedXml ) {
 604                                         $ret .= " $key";
 605                                 } else {
 606                                         $ret .= " $key=\"\"";
 607                                 }
 608                         } else {
 609                                 // Apparently we need to entity-encode \n, \r, \t, although the
 610                                 // spec doesn't mention that.  Since we're doing strtr() anyway,
 611                                 // and we don't need <> escaped here, we may as well not call
 612                                 // htmlspecialchars().
 613                                 // @todo FIXME: Verify that we actually need to
 614                                 // escape \n\r\t here, and explain why, exactly.
 615                                 #
 616                                 // We could call Sanitizer::encodeAttribute() for this, but we
 617                                 // don't because we're stubborn and like our marginal savings on
 618                                 // byte size from not having to encode unnecessary quotes.
 619                                 $map = array(
 620                                         '&' => '&amp;',
 621                                         '"' => '&quot;',
 622                                         "\n" => '&#10;',
 623                                         "\r" => '&#13;',
 624                                         "\t" => '&#9;'
 625                                 );
 626                                 if ( $wgWellFormedXml ) {
 627                                         // This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue>
 628                                         // But reportedly it breaks some XML tools?
 629                                         // @todo FIXME: Is this really true?
 630                                         $map['<'] = '&lt;';
 631                                 }
 632                                 $ret .= " $key=$quote" . strtr( $value, $map ) . $quote;
 633                         }
 634                 }
 635                 return $ret;
 636         }
 637
 638         /**
 639          * Output a "<script>" tag with the given contents.
 640          *
 641          * @todo do some useful escaping as well, like if $contents contains
 642          * literal "</script>" or (for XML) literal "]]>".
 643          *
 644          * @param string $contents JavaScript
 645          * @return string Raw HTML
 646          */
 647         public static function inlineScript( $contents ) {
 648                 global $wgWellFormedXml;
 649
 650                 $attrs = array();
 651
 652                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 653                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 654                 }
 655
 656                 return self::rawElement( 'script', $attrs, $contents );
 657         }
 658
 659         /**
 660          * Output a "<script>" tag linking to the given URL, e.g.,
 661          * "<script src=foo.js></script>".
 662          *
 663          * @param string $url
 664          * @return string Raw HTML
 665          */
 666         public static function linkedScript( $url ) {
 667                 $attrs = array( 'src' => $url );
 668
 669                 return self::element( 'script', $attrs );
 670         }
 671
 672         /**
 673          * Output a "<style>" tag with the given contents for the given media type
 674          * (if any).  TODO: do some useful escaping as well, like if $contents
 675          * contains literal "</style>" (admittedly unlikely).
 676          *
 677          * @param string $contents CSS
 678          * @param string $media A media type string, like 'screen'
 679          * @return string Raw HTML
 680          */
 681         public static function inlineStyle( $contents, $media = 'all' ) {
 682                 global $wgWellFormedXml;
 683
 684                 if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) {
 685                         $contents = "/*<![CDATA[*/$contents/*]]>*/";
 686                 }
 687
 688                 return self::rawElement( 'style', array(
 689                         'type' => 'text/css',
 690                         'media' => $media,
 691                 ), $contents );
 692         }
 693
 694         /**
 695          * Output a "<link rel=stylesheet>" linking to the given URL for the given
 696          * media type (if any).
 697          *
 698          * @param string $url
 699          * @param string $media A media type string, like 'screen'
 700          * @return string Raw HTML
 701          */
 702         public static function linkedStyle( $url, $media = 'all' ) {
 703                 return self::element( 'link', array(
 704                         'rel' => 'stylesheet',
 705                         'href' => $url,
 706                         'type' => 'text/css',
 707                         'media' => $media,
 708                 ) );
 709         }
 710
 711         /**
 712          * Convenience function to produce an "<input>" element.  This supports the
 713          * new HTML5 input types and attributes.
 714          *
 715          * @param string $name Name attribute
 716          * @param array $value Value attribute
 717          * @param string $type Type attribute
 718          * @param array $attribs Associative array of miscellaneous extra
 719          *   attributes, passed to Html::element()
 720          * @return string Raw HTML
 721          */
 722         public static function input( $name, $value = '', $type = 'text', $attribs = array() ) {
 723                 $attribs['type'] = $type;
 724                 $attribs['value'] = $value;
 725                 $attribs['name'] = $name;
 726                 if ( in_array( $type, array( 'text', 'search', 'email', 'password', 'number' ) ) ) {
 727                         $attribs = Html::getTextInputAttributes( $attribs );
 728                 }
 729                 return self::element( 'input', $attribs );
 730         }
 731
 732         /**
 733          * Convenience function to produce a checkbox (input element with type=checkbox)
 734          *
 735          * @param string $name Name attribute
 736          * @param bool $checked Whether the checkbox is checked or not
 737          * @param array $attribs Array of additional attributes
 738          * @return string
 739          */
 740         public static function check( $name, $checked = false, array $attribs = array() ) {
 741                 if ( isset( $attribs['value'] ) ) {
 742                         $value = $attribs['value'];
 743                         unset( $attribs['value'] );
 744                 } else {
 745                         $value = 1;
 746                 }
 747
 748                 if ( $checked ) {
 749                         $attribs[] = 'checked';
 750                 }
 751
 752                 return self::input( $name, $value, 'checkbox', $attribs );
 753         }
 754
 755         /**
 756          * Convenience function to produce a checkbox (input element with type=checkbox)
 757          *
 758          * @param string $name Name attribute
 759          * @param bool $checked Whether the checkbox is checked or not
 760          * @param array $attribs Array of additional attributes
 761          * @return string
 762          */
 763         public static function radio( $name, $checked = false, array $attribs = array() ) {
 764                 if ( isset( $attribs['value'] ) ) {
 765                         $value = $attribs['value'];
 766                         unset( $attribs['value'] );
 767                 } else {
 768                         $value = 1;
 769                 }
 770
 771                 if ( $checked ) {
 772                         $attribs[] = 'checked';
 773                 }
 774
 775                 return self::input( $name, $value, 'radio', $attribs );
 776         }
 777
 778         /**
 779          * Convenience function for generating a label for inputs.
 780          *
 781          * @param string $label Contents of the label
 782          * @param string $id ID of the element being labeled
 783          * @param array $attribs Additional attributes
 784          * @return string
 785          */
 786         public static function label( $label, $id, array $attribs = array() ) {
 787                 $attribs += array(
 788                         'for' => $id
 789                 );
 790                 return self::element( 'label', $attribs, $label );
 791         }
 792
 793         /**
 794          * Convenience function to produce an input element with type=hidden
 795          *
 796          * @param string $name Name attribute
 797          * @param string $value Value attribute
 798          * @param array $attribs Associative array of miscellaneous extra
 799          *   attributes, passed to Html::element()
 800          * @return string Raw HTML
 801          */
 802         public static function hidden( $name, $value, $attribs = array() ) {
 803                 return self::input( $name, $value, 'hidden', $attribs );
 804         }
 805
 806         /**
 807          * Convenience function to produce a <textarea> element.
 808          *
 809          * This supports leaving out the cols= and rows= which Xml requires and are
 810          * required by HTML4/XHTML but not required by HTML5.
 811          *
 812          * @param string $name Name attribute
 813          * @param string $value Value attribute
 814          * @param array $attribs Associative array of miscellaneous extra
 815          *   attributes, passed to Html::element()
 816          * @return string Raw HTML
 817          */
 818         public static function textarea( $name, $value = '', $attribs = array() ) {
 819                 $attribs['name'] = $name;
 820
 821                 if ( substr( $value, 0, 1 ) == "\n" ) {
 822                         // Workaround for bug 12130: browsers eat the initial newline
 823                         // assuming that it's just for show, but they do keep the later
 824                         // newlines, which we may want to preserve during editing.
 825                         // Prepending a single newline
 826                         $spacedValue = "\n" . $value;
 827                 } else {
 828                         $spacedValue = $value;
 829                 }
 830                 return self::element( 'textarea', Html::getTextInputAttributes( $attribs ), $spacedValue );
 831         }
 832
 833         /**
 834          * Build a drop-down box for selecting a namespace
 835          *
 836          * @param array $params Params to set.
 837          * - selected: [optional] Id of namespace which should be pre-selected
 838          * - all: [optional] Value of item for "all namespaces". If null or unset,
 839          *   no "<option>" is generated to select all namespaces.
 840          * - label: text for label to add before the field.
 841          * - exclude: [optional] Array of namespace ids to exclude.
 842          * - disable: [optional] Array of namespace ids for which the option should
 843          *   be disabled in the selector.
 844          * @param array $selectAttribs HTML attributes for the generated select element.
 845          * - id:   [optional], default: 'namespace'.
 846          * - name: [optional], default: 'namespace'.
 847          * @return string HTML code to select a namespace.
 848          */
 849         public static function namespaceSelector( array $params = array(),
 850                 array $selectAttribs = array()
 851         ) {
 852                 global $wgContLang;
 853
 854                 ksort( $selectAttribs );
 855
 856                 // Is a namespace selected?
 857                 if ( isset( $params['selected'] ) ) {
 858                         // If string only contains digits, convert to clean int. Selected could also
 859                         // be "all" or "" etc. which needs to be left untouched.
 860                         // PHP is_numeric() has issues with large strings, PHP ctype_digit has other issues
 861                         // and returns false for already clean ints. Use regex instead..
 862                         if ( preg_match( '/^\d+$/', $params['selected'] ) ) {
 863                                 $params['selected'] = intval( $params['selected'] );
 864                         }
 865                         // else: leaves it untouched for later processing
 866                 } else {
 867                         $params['selected'] = '';
 868                 }
 869
 870                 if ( !isset( $params['exclude'] ) || !is_array( $params['exclude'] ) ) {
 871                         $params['exclude'] = array();
 872                 }
 873                 if ( !isset( $params['disable'] ) || !is_array( $params['disable'] ) ) {
 874                         $params['disable'] = array();
 875                 }
 876
 877                 // Associative array between option-values and option-labels
 878                 $options = array();
 879
 880                 if ( isset( $params['all'] ) ) {
 881                         // add an option that would let the user select all namespaces.
 882                         // Value is provided by user, the name shown is localized for the user.
 883                         $options[$params['all']] = wfMessage( 'namespacesall' )->text();
 884                 }
 885                 // Add all namespaces as options (in the content language)
 886                 $options += $wgContLang->getFormattedNamespaces();
 887
 888                 // Convert $options to HTML and filter out namespaces below 0
 889                 $optionsHtml = array();
 890                 foreach ( $options as $nsId => $nsName ) {
 891                         if ( $nsId < NS_MAIN || in_array( $nsId, $params['exclude'] ) ) {
 892                                 continue;
 893                         }
 894                         if ( $nsId === NS_MAIN ) {
 895                                 // For other namespaces use the namespace prefix as label, but for
 896                                 // main we don't use "" but the user message describing it (e.g. "(Main)" or "(Article)")
 897                                 $nsName = wfMessage( 'blanknamespace' )->text();
 898                         } elseif ( is_int( $nsId ) ) {
 899                                 $nsName = $wgContLang->convertNamespace( $nsId );
 900                         }
 901                         $optionsHtml[] = Html::element(
 902                                 'option', array(
 903                                         'disabled' => in_array( $nsId, $params['disable'] ),
 904                                         'value' => $nsId,
 905                                         'selected' => $nsId === $params['selected'],
 906                                 ), $nsName
 907                         );
 908                 }
 909
 910                 if ( !array_key_exists( 'id', $selectAttribs ) ) {
 911                         $selectAttribs['id'] = 'namespace';
 912                 }
 913
 914                 if ( !array_key_exists( 'name', $selectAttribs ) ) {
 915                         $selectAttribs['name'] = 'namespace';
 916                 }
 917
 918                 $ret = '';
 919                 if ( isset( $params['label'] ) ) {
 920                         $ret .= Html::element(
 921                                 'label', array(
 922                                         'for' => isset( $selectAttribs['id'] ) ? $selectAttribs['id'] : null,
 923                                 ), $params['label']
 924                         ) . '&#160;';
 925                 }
 926
 927                 // Wrap options in a <select>
 928                 $ret .= Html::openElement( 'select', $selectAttribs )
 929                         . "\n"
 930                         . implode( "\n", $optionsHtml )
 931                         . "\n"
 932                         . Html::closeElement( 'select' );
 933
 934                 return $ret;
 935         }
 936
 937         /**
 938          * Constructs the opening html-tag with necessary doctypes depending on
 939          * global variables.
 940          *
 941          * @param array $attribs Associative array of miscellaneous extra
 942          *   attributes, passed to Html::element() of html tag.
 943          * @return string Raw HTML
 944          */
 945         public static function htmlHeader( $attribs = array() ) {
 946                 $ret = '';
 947
 948                 global $wgHtml5Version, $wgMimeType, $wgXhtmlNamespaces;
 949
 950                 $isXHTML = self::isXmlMimeType( $wgMimeType );
 951
 952                 if ( $isXHTML ) { // XHTML5
 953                         // XML MIME-typed markup should have an xml header.
 954                         // However a DOCTYPE is not needed.
 955                         $ret .= "<?xml version=\"1.0\" encoding=\"UTF-8\" ?" . ">\n";
 956
 957                         // Add the standard xmlns
 958                         $attribs['xmlns'] = 'http://www.w3.org/1999/xhtml';
 959
 960                         // And support custom namespaces
 961                         foreach ( $wgXhtmlNamespaces as $tag => $ns ) {
 962                                 $attribs["xmlns:$tag"] = $ns;
 963                         }
 964                 } else { // HTML5
 965                         // DOCTYPE
 966                         $ret .= "<!DOCTYPE html>\n";
 967                 }
 968
 969                 if ( $wgHtml5Version ) {
 970                         $attribs['version'] = $wgHtml5Version;
 971                 }
 972
 973                 $html = Html::openElement( 'html', $attribs );
 974
 975                 if ( $html ) {
 976                         $html .= "\n";
 977                 }
 978
 979                 $ret .= $html;
 980
 981                 return $ret;
 982         }
 983
 984         /**
 985          * Determines if the given MIME type is xml.
 986          *
 987          * @param string $mimetype MIME type
 988          * @return bool
 989          */
 990         public static function isXmlMimeType( $mimetype ) {
 991                 # http://www.whatwg.org/html/infrastructure.html#xml-mime-type
 992                 # * text/xml
 993                 # * application/xml
 994                 # * Any MIME type with a subtype ending in +xml (this implicitly includes application/xhtml+xml)
 995                 return (bool)preg_match( '!^(text|application)/xml$|^.+/.+\+xml$!', $mimetype );
 996         }
 997
 998         /**
 999          * Get HTML for an info box with an icon.
1000          *
1001          * @param string $text Wikitext, get this with wfMessage()->plain()
1002          * @param string $icon Path to icon file (used as 'src' attribute)
1003          * @param string $alt Alternate text for the icon
1004          * @param string $class Additional class name to add to the wrapper div
1005          *
1006          * @return string
1007          */
1008         static function infoBox( $text, $icon, $alt, $class = false ) {
1009                 $s = Html::openElement( 'div', array( 'class' => "mw-infobox $class" ) );
1010
1011                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-left' ) ) .
1012                                 Html::element( 'img',
1013                                         array(
1014                                                 'src' => $icon,
1015                                                 'alt' => $alt,
1016                                         )
1017                                 ) .
1018                                 Html::closeElement( 'div' );
1019
1020                 $s .= Html::openElement( 'div', array( 'class' => 'mw-infobox-right' ) ) .
1021                                 $text .
1022                                 Html::closeElement( 'div' );
1023                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
1024
1025                 $s .= Html::closeElement( 'div' );
1026
1027                 $s .= Html::element( 'div', array( 'style' => 'clear: left;' ), ' ' );
1028
1029                 return $s;
1030         }
1031
1032         /**
1033          * Generate a srcset attribute value from an array mapping pixel densities
1034          * to URLs. Note that srcset supports width and height values as well, which
1035          * are not used here.
1036          *
1037          * @param array $urls
1038          * @return string
1039          */
1040         static function srcSet( $urls ) {
1041                 $candidates = array();
1042                 foreach ( $urls as $density => $url ) {
1043                         // Image candidate syntax per current whatwg live spec, 2012-09-23:
1044                         // http://www.whatwg.org/html/embedded-content-1.html#attr-img-srcset
1045                         $candidates[] = "{$url} {$density}x";
1046                 }
1047                 return implode( ", ", $candidates );
1048         }
1049 }