sforkowany z mirror/friendica
136 wiersze
5.0 KiB
PHP
136 wiersze
5.0 KiB
PHP
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<?php
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/**
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* This filter extracts <style> blocks from input HTML, cleans them up
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* using CSSTidy, and then places them in $purifier->context->get('StyleBlocks')
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* so they can be used elsewhere in the document.
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*
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* @note
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* See tests/HTMLPurifier/Filter/ExtractStyleBlocksTest.php for
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* sample usage.
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*
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* @note
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* This filter can also be used on stylesheets not included in the
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* document--something purists would probably prefer. Just directly
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* call HTMLPurifier_Filter_ExtractStyleBlocks->cleanCSS()
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*/
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class HTMLPurifier_Filter_ExtractStyleBlocks extends HTMLPurifier_Filter
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{
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public $name = 'ExtractStyleBlocks';
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private $_styleMatches = array();
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private $_tidy;
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public function __construct() {
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$this->_tidy = new csstidy();
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}
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/**
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* Save the contents of CSS blocks to style matches
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* @param $matches preg_replace style $matches array
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*/
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protected function styleCallback($matches) {
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$this->_styleMatches[] = $matches[1];
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}
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/**
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* Removes inline <style> tags from HTML, saves them for later use
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* @todo Extend to indicate non-text/css style blocks
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*/
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public function preFilter($html, $config, $context) {
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$tidy = $config->get('Filter.ExtractStyleBlocks.TidyImpl');
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if ($tidy !== null) $this->_tidy = $tidy;
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$html = preg_replace_callback('#<style(?:\s.*)?>(.+)</style>#isU', array($this, 'styleCallback'), $html);
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$style_blocks = $this->_styleMatches;
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$this->_styleMatches = array(); // reset
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$context->register('StyleBlocks', $style_blocks); // $context must not be reused
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if ($this->_tidy) {
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foreach ($style_blocks as &$style) {
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$style = $this->cleanCSS($style, $config, $context);
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}
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}
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return $html;
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}
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/**
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* Takes CSS (the stuff found in <style>) and cleans it.
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* @warning Requires CSSTidy <http://csstidy.sourceforge.net/>
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* @param $css CSS styling to clean
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* @param $config Instance of HTMLPurifier_Config
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* @param $context Instance of HTMLPurifier_Context
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* @return Cleaned CSS
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*/
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public function cleanCSS($css, $config, $context) {
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// prepare scope
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$scope = $config->get('Filter.ExtractStyleBlocks.Scope');
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if ($scope !== null) {
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$scopes = array_map('trim', explode(',', $scope));
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} else {
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$scopes = array();
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}
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// remove comments from CSS
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$css = trim($css);
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if (strncmp('<!--', $css, 4) === 0) {
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$css = substr($css, 4);
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}
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if (strlen($css) > 3 && substr($css, -3) == '-->') {
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$css = substr($css, 0, -3);
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}
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$css = trim($css);
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$this->_tidy->parse($css);
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$css_definition = $config->getDefinition('CSS');
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foreach ($this->_tidy->css as $k => $decls) {
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// $decls are all CSS declarations inside an @ selector
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$new_decls = array();
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foreach ($decls as $selector => $style) {
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$selector = trim($selector);
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if ($selector === '') continue; // should not happen
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if ($selector[0] === '+') {
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if ($selector !== '' && $selector[0] === '+') continue;
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}
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if (!empty($scopes)) {
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$new_selector = array(); // because multiple ones are possible
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$selectors = array_map('trim', explode(',', $selector));
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foreach ($scopes as $s1) {
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foreach ($selectors as $s2) {
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$new_selector[] = "$s1 $s2";
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}
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}
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$selector = implode(', ', $new_selector); // now it's a string
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}
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foreach ($style as $name => $value) {
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if (!isset($css_definition->info[$name])) {
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unset($style[$name]);
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continue;
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}
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$def = $css_definition->info[$name];
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$ret = $def->validate($value, $config, $context);
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if ($ret === false) unset($style[$name]);
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else $style[$name] = $ret;
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}
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$new_decls[$selector] = $style;
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}
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$this->_tidy->css[$k] = $new_decls;
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}
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// remove stuff that shouldn't be used, could be reenabled
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// after security risks are analyzed
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$this->_tidy->import = array();
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$this->_tidy->charset = null;
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$this->_tidy->namespace = null;
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$css = $this->_tidy->print->plain();
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// we are going to escape any special characters <>& to ensure
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// that no funny business occurs (i.e. </style> in a font-family prop).
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if ($config->get('Filter.ExtractStyleBlocks.Escaping')) {
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$css = str_replace(
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array('<', '>', '&'),
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array('\3C ', '\3E ', '\26 '),
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$css
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);
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}
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return $css;
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}
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}
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// vim: et sw=4 sts=4
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