<?php /** * Parser that uses PHP 5's DOM extension (part of the core). * * In PHP 5, the DOM XML extension was revamped into DOM and added to the core. * It gives us a forgiving HTML parser, which we use to transform the HTML * into a DOM, and then into the tokens. It is blazingly fast (for large * documents, it performs twenty times faster than * HTMLPurifier_Lexer_DirectLex,and is the default choice for PHP 5. * * @note Any empty elements will have empty tokens associated with them, even if * this is prohibited by the spec. This is cannot be fixed until the spec * comes into play. * * @note PHP's DOM extension does not actually parse any entities, we use * our own function to do that. * * @warning DOM tends to drop whitespace, which may wreak havoc on indenting. * If this is a huge problem, due to the fact that HTML is hand * edited and you are unable to get a parser cache that caches the * the output of HTML Purifier while keeping the original HTML lying * around, you may want to run Tidy on the resulting output or use * HTMLPurifier_DirectLex */ class HTMLPurifier_Lexer_DOMLex extends HTMLPurifier_Lexer { private $factory; public function __construct() { // setup the factory parent::__construct(); $this->factory = new HTMLPurifier_TokenFactory(); } public function tokenizeHTML($html, $config, $context) { $html = $this->normalize($html, $config, $context); // attempt to armor stray angled brackets that cannot possibly // form tags and thus are probably being used as emoticons if ($config->get('Core.AggressivelyFixLt')) { $char = '[^a-z!\/]'; $comment = "/<!--(.*?)(-->|\z)/is"; $html = preg_replace_callback($comment, array($this, 'callbackArmorCommentEntities'), $html); do { $old = $html; $html = preg_replace("/<($char)/i", '<\\1', $html); } while ($html !== $old); $html = preg_replace_callback($comment, array($this, 'callbackUndoCommentSubst'), $html); // fix comments } // preprocess html, essential for UTF-8 $html = $this->wrapHTML($html, $config, $context); $doc = new DOMDocument(); $doc->encoding = 'UTF-8'; // theoretically, the above has this covered set_error_handler(array($this, 'muteErrorHandler')); $doc->loadHTML($html); restore_error_handler(); $tokens = array(); $this->tokenizeDOM( $doc->getElementsByTagName('html')->item(0)-> // <html> getElementsByTagName('body')->item(0)-> // <body> getElementsByTagName('div')->item(0) // <div> , $tokens); return $tokens; } /** * Recursive function that tokenizes a node, putting it into an accumulator. * * @param $node DOMNode to be tokenized. * @param $tokens Array-list of already tokenized tokens. * @param $collect Says whether or start and close are collected, set to * false at first recursion because it's the implicit DIV * tag you're dealing with. * @returns Tokens of node appended to previously passed tokens. */ protected function tokenizeDOM($node, &$tokens, $collect = false) { // intercept non element nodes. WE MUST catch all of them, // but we're not getting the character reference nodes because // those should have been preprocessed if ($node->nodeType === XML_TEXT_NODE) { $tokens[] = $this->factory->createText($node->data); return; } elseif ($node->nodeType === XML_CDATA_SECTION_NODE) { // undo libxml's special treatment of <script> and <style> tags $last = end($tokens); $data = $node->data; // (note $node->tagname is already normalized) if ($last instanceof HTMLPurifier_Token_Start && ($last->name == 'script' || $last->name == 'style')) { $new_data = trim($data); if (substr($new_data, 0, 4) === '<!--') { $data = substr($new_data, 4); if (substr($data, -3) === '-->') { $data = substr($data, 0, -3); } else { // Highly suspicious! Not sure what to do... } } } $tokens[] = $this->factory->createText($this->parseData($data)); return; } elseif ($node->nodeType === XML_COMMENT_NODE) { // this is code is only invoked for comments in script/style in versions // of libxml pre-2.6.28 (regular comments, of course, are still // handled regularly) $tokens[] = $this->factory->createComment($node->data); return; } elseif ( // not-well tested: there may be other nodes we have to grab $node->nodeType !== XML_ELEMENT_NODE ) { return; } $attr = $node->hasAttributes() ? $this->transformAttrToAssoc($node->attributes) : array(); // We still have to make sure that the element actually IS empty if (!$node->childNodes->length) { if ($collect) { $tokens[] = $this->factory->createEmpty($node->tagName, $attr); } } else { if ($collect) { // don't wrap on first iteration $tokens[] = $this->factory->createStart( $tag_name = $node->tagName, // somehow, it get's dropped $attr ); } foreach ($node->childNodes as $node) { // remember, it's an accumulator. Otherwise, we'd have // to use array_merge $this->tokenizeDOM($node, $tokens, true); } if ($collect) { $tokens[] = $this->factory->createEnd($tag_name); } } } /** * Converts a DOMNamedNodeMap of DOMAttr objects into an assoc array. * * @param $attribute_list DOMNamedNodeMap of DOMAttr objects. * @returns Associative array of attributes. */ protected function transformAttrToAssoc($node_map) { // NamedNodeMap is documented very well, so we're using undocumented // features, namely, the fact that it implements Iterator and // has a ->length attribute if ($node_map->length === 0) return array(); $array = array(); foreach ($node_map as $attr) { $array[$attr->name] = $attr->value; } return $array; } /** * An error handler that mutes all errors */ public function muteErrorHandler($errno, $errstr) {} /** * Callback function for undoing escaping of stray angled brackets * in comments */ public function callbackUndoCommentSubst($matches) { return '<!--' . strtr($matches[1], array('&'=>'&','<'=>'<')) . $matches[2]; } /** * Callback function that entity-izes ampersands in comments so that * callbackUndoCommentSubst doesn't clobber them */ public function callbackArmorCommentEntities($matches) { return '<!--' . str_replace('&', '&', $matches[1]) . $matches[2]; } /** * Wraps an HTML fragment in the necessary HTML */ protected function wrapHTML($html, $config, $context) { $def = $config->getDefinition('HTML'); $ret = ''; if (!empty($def->doctype->dtdPublic) || !empty($def->doctype->dtdSystem)) { $ret .= '<!DOCTYPE html '; if (!empty($def->doctype->dtdPublic)) $ret .= 'PUBLIC "' . $def->doctype->dtdPublic . '" '; if (!empty($def->doctype->dtdSystem)) $ret .= '"' . $def->doctype->dtdSystem . '" '; $ret .= '>'; } $ret .= '<html><head>'; $ret .= '<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />'; // No protection if $html contains a stray </div>! $ret .= '</head><body><div>'.$html.'</div></body></html>'; return $ret; } } // vim: et sw=4 sts=4