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Diffstat (limited to 'includes/Html.php')
| -rw-r--r-- | includes/Html.php | 539 |
1 files changed, 539 insertions, 0 deletions
diff --git a/includes/Html.php b/includes/Html.php new file mode 100644 index 00000000..00183b31 --- /dev/null +++ b/includes/Html.php @@ -0,0 +1,539 @@ +<?php +# Copyright (C) 2009 Aryeh Gregor +# http://www.mediawiki.org/ +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, write to the Free Software Foundation, Inc., +# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +# http://www.gnu.org/copyleft/gpl.html + +/** + * This class is a collection of static functions that serve two purposes: + * + * 1) Implement any algorithms specified by HTML5, or other HTML + * specifications, in a convenient and self-contained way. + * + * 2) Allow HTML elements to be conveniently and safely generated, like the + * current Xml class but a) less confused (Xml supports HTML-specific things, + * but only sometimes!) and b) not necessarily confined to XML-compatible + * output. + * + * There are two important configuration options this class uses: + * + * $wgHtml5: If this is set to false, then all output should be valid XHTML 1.0 + * Transitional. + * $wgWellFormedXml: If this is set to true, then all output should be + * well-formed XML (quotes on attributes, self-closing tags, etc.). + * + * This class is meant to be confined to utility functions that are called from + * trusted code paths. It does not do enforcement of policy like not allowing + * <a> elements. + */ +class Html { + # List of void elements from HTML5, section 9.1.2 as of 2009-08-10 + private static $voidElements = array( + 'area', + 'base', + 'br', + 'col', + 'command', + 'embed', + 'hr', + 'img', + 'input', + 'keygen', + 'link', + 'meta', + 'param', + 'source', + ); + + # Boolean attributes, which may have the value omitted entirely. Manually + # collected from the HTML5 spec as of 2009-08-10. + private static $boolAttribs = array( + 'async', + 'autobuffer', + 'autofocus', + 'autoplay', + 'checked', + 'controls', + 'defer', + 'disabled', + 'formnovalidate', + 'hidden', + 'ismap', + 'loop', + 'multiple', + 'novalidate', + 'open', + 'readonly', + 'required', + 'reversed', + 'scoped', + 'seamless', + ); + + /** + * Returns an HTML element in a string. The major advantage here over + * manually typing out the HTML is that it will escape all attribute + * values. If you're hardcoding all the attributes, or there are none, you + * should probably type out the string yourself. + * + * This is quite similar to Xml::tags(), but it implements some useful + * HTML-specific logic. For instance, there is no $allowShortTag + * parameter: the closing tag is magically omitted if $element has an empty + * content model. If $wgWellFormedXml is false, then a few bytes will be + * shaved off the HTML output as well. In the future, other HTML-specific + * features might be added, like allowing arrays for the values of + * attributes like class= and media=. + * + * @param $element string The element's name, e.g., 'a' + * @param $attribs array Associative array of attributes, e.g., array( + * 'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for + * further documentation. + * @param $contents string The raw HTML contents of the element: *not* + * escaped! + * @return string Raw HTML + */ + public static function rawElement( $element, $attribs = array(), $contents = '' ) { + global $wgWellFormedXml; + $start = self::openElement( $element, $attribs ); + if ( in_array( $element, self::$voidElements ) ) { + if ( $wgWellFormedXml ) { + # Silly XML. + return substr( $start, 0, -1 ) . ' />'; + } + return $start; + } else { + return "$start$contents</$element>"; + } + } + + /** + * Identical to rawElement(), but HTML-escapes $contents (like + * Xml::element()). + */ + public static function element( $element, $attribs = array(), $contents = '' ) { + return self::rawElement( $element, $attribs, strtr( $contents, array( + # There's no point in escaping quotes, >, etc. in the contents of + # elements. + '&' => '&', + '<' => '<' + ) ) ); + } + + /** + * Identical to rawElement(), but has no third parameter and omits the end + * tag (and the self-closing / in XML mode for empty elements). + */ + public static function openElement( $element, $attribs = array() ) { + global $wgHtml5; + $attribs = (array)$attribs; + # This is not required in HTML5, but let's do it anyway, for + # consistency and better compression. + $element = strtolower( $element ); + + # Remove HTML5-only attributes if we aren't doing HTML5, and disable + # form validation regardless (see bug 23769 and the more detailed + # comment in expandAttributes()) + if ( $element == 'input' ) { + # Whitelist of types that don't cause validation. All except + # 'search' are valid in XHTML1. + $validTypes = array( + 'hidden', + 'text', + 'password', + 'checkbox', + 'radio', + 'file', + 'submit', + 'image', + 'reset', + 'button', + 'search', + ); + if ( isset( $attribs['type'] ) + && !in_array( $attribs['type'], $validTypes ) ) { + unset( $attribs['type'] ); + } + if ( isset( $attribs['type'] ) && $attribs['type'] == 'search' + && !$wgHtml5 ) { + unset( $attribs['type'] ); + } + # Here we're blacklisting some HTML5-only attributes... + $html5attribs = array( + 'autocomplete', + 'autofocus', + 'max', + 'min', + 'multiple', + 'pattern', + 'placeholder', + 'required', + 'step', + 'spellcheck', + ); + foreach ( $html5attribs as $badAttr ) { + unset( $attribs[$badAttr] ); + } + } + if ( !$wgHtml5 && $element == 'textarea' && isset( $attribs['maxlength'] ) ) { + unset( $attribs['maxlength'] ); + } + + return "<$element" . self::expandAttributes( + self::dropDefaults( $element, $attribs ) ) . '>'; + } + + /** + * Given an element name and an associative array of element attributes, + * return an array that is functionally identical to the input array, but + * possibly smaller. In particular, attributes might be stripped if they + * are given their default values. + * + * This method is not guaranteed to remove all redundant attributes, only + * some common ones and some others selected arbitrarily at random. It + * only guarantees that the output array should be functionally identical + * to the input array (currently per the HTML 5 draft as of 2009-09-06). + * + * @param $element string Name of the element, e.g., 'a' + * @param $attribs array Associative array of attributes, e.g., array( + * 'href' => 'http://www.mediawiki.org/' ). See expandAttributes() for + * further documentation. + * @return array An array of attributes functionally identical to $attribs + */ + private static function dropDefaults( $element, $attribs ) { + # Don't bother doing anything if we aren't outputting HTML5; it's too + # much of a pain to maintain two sets of defaults. + global $wgHtml5; + if ( !$wgHtml5 ) { + return $attribs; + } + + static $attribDefaults = array( + 'area' => array( 'shape' => 'rect' ), + 'button' => array( + 'formaction' => 'GET', + 'formenctype' => 'application/x-www-form-urlencoded', + 'type' => 'submit', + ), + 'canvas' => array( + 'height' => '150', + 'width' => '300', + ), + 'command' => array( 'type' => 'command' ), + 'form' => array( + 'action' => 'GET', + 'autocomplete' => 'on', + 'enctype' => 'application/x-www-form-urlencoded', + ), + 'input' => array( + 'formaction' => 'GET', + 'type' => 'text', + 'value' => '', + ), + 'keygen' => array( 'keytype' => 'rsa' ), + 'link' => array( 'media' => 'all' ), + 'menu' => array( 'type' => 'list' ), + # Note: the use of text/javascript here instead of other JavaScript + # MIME types follows the HTML5 spec. + 'script' => array( 'type' => 'text/javascript' ), + 'style' => array( + 'media' => 'all', + 'type' => 'text/css', + ), + 'textarea' => array( 'wrap' => 'soft' ), + ); + + $element = strtolower( $element ); + + foreach ( $attribs as $attrib => $value ) { + $lcattrib = strtolower( $attrib ); + $value = strval( $value ); + + # Simple checks using $attribDefaults + if ( isset( $attribDefaults[$element][$lcattrib] ) && + $attribDefaults[$element][$lcattrib] == $value ) { + unset( $attribs[$attrib] ); + } + + if ( $lcattrib == 'class' && $value == '' ) { + unset( $attribs[$attrib] ); + } + } + + # More subtle checks + if ( $element === 'link' && isset( $attribs['type'] ) + && strval( $attribs['type'] ) == 'text/css' ) { + unset( $attribs['type'] ); + } + if ( $element === 'select' && isset( $attribs['size'] ) ) { + if ( in_array( 'multiple', $attribs ) + || ( isset( $attribs['multiple'] ) && $attribs['multiple'] !== false ) + ) { + # A multi-select + if ( strval( $attribs['size'] ) == '4' ) { + unset( $attribs['size'] ); + } + } else { + # Single select + if ( strval( $attribs['size'] ) == '1' ) { + unset( $attribs['size'] ); + } + } + } + + return $attribs; + } + + /** + * Given an associative array of element attributes, generate a string + * to stick after the element name in HTML output. Like array( 'href' => + * 'http://www.mediawiki.org/' ) becomes something like + * ' href="http://www.mediawiki.org"'. Again, this is like + * Xml::expandAttributes(), but it implements some HTML-specific logic. + * For instance, it will omit quotation marks if $wgWellFormedXml is false, + * and will treat boolean attributes specially. + * + * @param $attribs array Associative array of attributes, e.g., array( + * 'href' => 'http://www.mediawiki.org/' ). Values will be HTML-escaped. + * A value of false means to omit the attribute. For boolean attributes, + * you can omit the key, e.g., array( 'checked' ) instead of + * array( 'checked' => 'checked' ) or such. + * @return string HTML fragment that goes between element name and '>' + * (starting with a space if at least one attribute is output) + */ + public static function expandAttributes( $attribs ) { + global $wgHtml5, $wgWellFormedXml; + + $ret = ''; + $attribs = (array)$attribs; + foreach ( $attribs as $key => $value ) { + if ( $value === false ) { + continue; + } + + # For boolean attributes, support array( 'foo' ) instead of + # requiring array( 'foo' => 'meaningless' ). + if ( is_int( $key ) + && in_array( strtolower( $value ), self::$boolAttribs ) ) { + $key = $value; + } + + # Not technically required in HTML5, but required in XHTML 1.0, + # and we'd like consistency and better compression anyway. + $key = strtolower( $key ); + + # Bug 23769: Blacklist all form validation attributes for now. Current + # (June 2010) WebKit has no UI, so the form just refuses to submit + # without telling the user why, which is much worse than failing + # server-side validation. Opera is the only other implementation at + # this time, and has ugly UI, so just kill the feature entirely until + # we have at least one good implementation. + if ( in_array( $key, array( 'max', 'min', 'pattern', 'required', 'step' ) ) ) { + continue; + } + + # See the "Attributes" section in the HTML syntax part of HTML5, + # 9.1.2.3 as of 2009-08-10. Most attributes can have quotation + # marks omitted, but not all. (Although a literal " is not + # permitted, we don't check for that, since it will be escaped + # anyway.) + # + # See also research done on further characters that need to be + # escaped: http://code.google.com/p/html5lib/issues/detail?id=93 + $badChars = "\\x00- '=<>`/\x{00a0}\x{1680}\x{180e}\x{180F}\x{2000}\x{2001}" + . "\x{2002}\x{2003}\x{2004}\x{2005}\x{2006}\x{2007}\x{2008}\x{2009}" + . "\x{200A}\x{2028}\x{2029}\x{202F}\x{205F}\x{3000}"; + if ( $wgWellFormedXml || $value === '' + || preg_match( "![$badChars]!u", $value ) ) { + $quote = '"'; + } else { + $quote = ''; + } + + if ( in_array( $key, self::$boolAttribs ) ) { + # In XHTML 1.0 Transitional, the value needs to be equal to the + # key. In HTML5, we can leave the value empty instead. If we + # don't need well-formed XML, we can omit the = entirely. + if ( !$wgWellFormedXml ) { + $ret .= " $key"; + } elseif ( $wgHtml5 ) { + $ret .= " $key=\"\""; + } else { + $ret .= " $key=\"$key\""; + } + } else { + # Apparently we need to entity-encode \n, \r, \t, although the + # spec doesn't mention that. Since we're doing strtr() anyway, + # and we don't need <> escaped here, we may as well not call + # htmlspecialchars(). FIXME: verify that we actually need to + # escape \n\r\t here, and explain why, exactly. + # + # We could call Sanitizer::encodeAttribute() for this, but we + # don't because we're stubborn and like our marginal savings on + # byte size from not having to encode unnecessary quotes. + $map = array( + '&' => '&', + '"' => '"', + "\n" => ' ', + "\r" => ' ', + "\t" => '	' + ); + if ( $wgWellFormedXml ) { + # This is allowed per spec: <http://www.w3.org/TR/xml/#NT-AttValue> + # But reportedly it breaks some XML tools? FIXME: is this + # really true? + $map['<'] = '<'; + } + $ret .= " $key=$quote" . strtr( $value, $map ) . $quote; + } + } + return $ret; + } + + /** + * Output a <script> tag with the given contents. TODO: do some useful + * escaping as well, like if $contents contains literal '</script>' or (for + * XML) literal "]]>". + * + * @param $contents string JavaScript + * @return string Raw HTML + */ + public static function inlineScript( $contents ) { + global $wgHtml5, $wgJsMimeType, $wgWellFormedXml; + + $attrs = array(); + if ( !$wgHtml5 ) { + $attrs['type'] = $wgJsMimeType; + } + if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) { + $contents = "/*<![CDATA[*/$contents/*]]>*/"; + } + return self::rawElement( 'script', $attrs, $contents ); + } + + /** + * Output a <script> tag linking to the given URL, e.g., + * <script src=foo.js></script>. + * + * @param $url string + * @return string Raw HTML + */ + public static function linkedScript( $url ) { + global $wgHtml5, $wgJsMimeType; + + $attrs = array( 'src' => $url ); + if ( !$wgHtml5 ) { + $attrs['type'] = $wgJsMimeType; + } + return self::element( 'script', $attrs ); + } + + /** + * Output a <style> tag with the given contents for the given media type + * (if any). TODO: do some useful escaping as well, like if $contents + * contains literal '</style>' (admittedly unlikely). + * + * @param $contents string CSS + * @param $media mixed A media type string, like 'screen' + * @return string Raw HTML + */ + public static function inlineStyle( $contents, $media = 'all' ) { + global $wgWellFormedXml; + + if ( $wgWellFormedXml && preg_match( '/[<&]/', $contents ) ) { + $contents = "/*<![CDATA[*/$contents/*]]>*/"; + } + return self::rawElement( 'style', array( + 'type' => 'text/css', + 'media' => $media, + ), $contents ); + } + + /** + * Output a <link rel=stylesheet> linking to the given URL for the given + * media type (if any). + * + * @param $url string + * @param $media mixed A media type string, like 'screen' + * @return string Raw HTML + */ + public static function linkedStyle( $url, $media = 'all' ) { + return self::element( 'link', array( + 'rel' => 'stylesheet', + 'href' => $url, + 'type' => 'text/css', + 'media' => $media, + ) ); + } + + /** + * Convenience function to produce an <input> element. This supports the + * new HTML5 input types and attributes, and will silently strip them if + * $wgHtml5 is false. + * + * @param $name string name attribute + * @param $value mixed value attribute + * @param $type string type attribute + * @param $attribs array Associative array of miscellaneous extra + * attributes, passed to Html::element() + * @return string Raw HTML + */ + public static function input( $name, $value = '', $type = 'text', $attribs = array() ) { + $attribs['type'] = $type; + $attribs['value'] = $value; + $attribs['name'] = $name; + + return self::element( 'input', $attribs ); + } + + /** + * Convenience function to produce an input element with type=hidden, like + * Xml::hidden. + * + * @param $name string name attribute + * @param $value string value attribute + * @param $attribs array Associative array of miscellaneous extra + * attributes, passed to Html::element() + * @return string Raw HTML + */ + public static function hidden( $name, $value, $attribs = array() ) { + return self::input( $name, $value, 'hidden', $attribs ); + } + + /** + * Convenience function to produce an <input> element. This supports leaving + * out the cols= and rows= which Xml requires and are required by HTML4/XHTML + * but not required by HTML5 and will silently set cols="" and rows="" if + * $wgHtml5 is false and cols and rows are omitted (HTML4 validates present + * but empty cols="" and rows="" as valid). + * + * @param $name string name attribute + * @param $value string value attribute + * @param $attribs array Associative array of miscellaneous extra + * attributes, passed to Html::element() + * @return string Raw HTML + */ + public static function textarea( $name, $value = '', $attribs = array() ) { + global $wgHtml5; + $attribs['name'] = $name; + if ( !$wgHtml5 ) { + if ( !isset( $attribs['cols'] ) ) + $attribs['cols'] = ""; + if ( !isset( $attribs['rows'] ) ) + $attribs['rows'] = ""; + } + return self::element( 'textarea', $attribs, $value ); + } +} |