PHPXRef 0.7.1 : Unnamed Project : /lib/htmlpurifier/HTMLPurifier/Lexer/DOMLex.php source

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   1  <?php
   2  
   3  /**
   4   * Parser that uses PHP 5's DOM extension (part of the core).
   5   *
   6   * In PHP 5, the DOM XML extension was revamped into DOM and added to the core.
   7   * It gives us a forgiving HTML parser, which we use to transform the HTML
   8   * into a DOM, and then into the tokens.  It is blazingly fast (for large
   9   * documents, it performs twenty times faster than
  10   * HTMLPurifier_Lexer_DirectLex,and is the default choice for PHP 5.
  11   *
  12   * @note Any empty elements will have empty tokens associated with them, even if
  13   * this is prohibited by the spec. This is cannot be fixed until the spec
  14   * comes into play.
  15   *
  16   * @note PHP's DOM extension does not actually parse any entities, we use
  17   *       our own function to do that.
  18   *
  19   * @warning DOM tends to drop whitespace, which may wreak havoc on indenting.
  20   *          If this is a huge problem, due to the fact that HTML is hand
  21   *          edited and you are unable to get a parser cache that caches the
  22   *          the output of HTML Purifier while keeping the original HTML lying
  23   *          around, you may want to run Tidy on the resulting output or use
  24   *          HTMLPurifier_DirectLex
  25   */
  26  
  27  class HTMLPurifier_Lexer_DOMLex extends HTMLPurifier_Lexer
  28  {
  29  
  30      /**
  31       * @type HTMLPurifier_TokenFactory
  32       */
  33      private $factory;
  34  
  35      public function __construct()
  36      {
  37          // setup the factory
  38          parent::__construct();
  39          $this->factory = new HTMLPurifier_TokenFactory();
  40      }
  41  
  42      /**
  43       * @param string $html
  44       * @param HTMLPurifier_Config $config
  45       * @param HTMLPurifier_Context $context
  46       * @return HTMLPurifier_Token[]
  47       */
  48      public function tokenizeHTML($html, $config, $context)
  49      {
  50          $html = $this->normalize($html, $config, $context);
  51  
  52          // attempt to armor stray angled brackets that cannot possibly
  53          // form tags and thus are probably being used as emoticons
  54          if ($config->get('Core.AggressivelyFixLt')) {
  55              $char = '[^a-z!\/]';
  56              $comment = "/<!--(.*?)(-->|\z)/is";
  57              $html = preg_replace_callback($comment, array($this, 'callbackArmorCommentEntities'), $html);
  58              do {
  59                  $old = $html;
  60                  $html = preg_replace("/<($char)/i", '&lt;\\1', $html);
  61              } while ($html !== $old);
  62              $html = preg_replace_callback($comment, array($this, 'callbackUndoCommentSubst'), $html); // fix comments
  63          }
  64  
  65          // preprocess html, essential for UTF-8
  66          $html = $this->wrapHTML($html, $config, $context);
  67  
  68          $doc = new DOMDocument();
  69          $doc->encoding = 'UTF-8'; // theoretically, the above has this covered
  70  
  71          set_error_handler(array($this, 'muteErrorHandler'));
  72          $doc->loadHTML($html);
  73          restore_error_handler();
  74  
  75          $tokens = array();
  76          $this->tokenizeDOM(
  77              $doc->getElementsByTagName('html')->item(0)-> // <html>
  78              getElementsByTagName('body')->item(0), //   <body>
  79              $tokens
  80          );
  81          return $tokens;
  82      }
  83  
  84      /**
  85       * Iterative function that tokenizes a node, putting it into an accumulator.
  86       * To iterate is human, to recurse divine - L. Peter Deutsch
  87       * @param DOMNode $node DOMNode to be tokenized.
  88       * @param HTMLPurifier_Token[] $tokens   Array-list of already tokenized tokens.
  89       * @return HTMLPurifier_Token of node appended to previously passed tokens.
  90       */
  91      protected function tokenizeDOM($node, &$tokens)
  92      {
  93          $level = 0;
  94          $nodes = array($level => new HTMLPurifier_Queue(array($node)));
  95          $closingNodes = array();
  96          do {
  97              while (!$nodes[$level]->isEmpty()) {
  98                  $node = $nodes[$level]->shift(); // FIFO
  99                  $collect = $level > 0 ? true : false;
 100                  $needEndingTag = $this->createStartNode($node, $tokens, $collect);
 101                  if ($needEndingTag) {
 102                      $closingNodes[$level][] = $node;
 103                  }
 104                  if ($node->childNodes && $node->childNodes->length) {
 105                      $level++;
 106                      $nodes[$level] = new HTMLPurifier_Queue();
 107                      foreach ($node->childNodes as $childNode) {
 108                          $nodes[$level]->push($childNode);
 109                      }
 110                  }
 111              }
 112              $level--;
 113              if ($level && isset($closingNodes[$level])) {
 114                  while ($node = array_pop($closingNodes[$level])) {
 115                      $this->createEndNode($node, $tokens);
 116                  }
 117              }
 118          } while ($level > 0);
 119      }
 120  
 121      /**
 122       * @param DOMNode $node DOMNode to be tokenized.
 123       * @param HTMLPurifier_Token[] $tokens   Array-list of already tokenized tokens.
 124       * @param bool $collect  Says whether or start and close are collected, set to
 125       *                    false at first recursion because it's the implicit DIV
 126       *                    tag you're dealing with.
 127       * @return bool if the token needs an endtoken
 128       * @todo data and tagName properties don't seem to exist in DOMNode?
 129       */
 130      protected function createStartNode($node, &$tokens, $collect)
 131      {
 132          // intercept non element nodes. WE MUST catch all of them,
 133          // but we're not getting the character reference nodes because
 134          // those should have been preprocessed
 135          if ($node->nodeType === XML_TEXT_NODE) {
 136              $tokens[] = $this->factory->createText($node->data);
 137              return false;
 138          } elseif ($node->nodeType === XML_CDATA_SECTION_NODE) {
 139              // undo libxml's special treatment of <script> and <style> tags
 140              $last = end($tokens);
 141              $data = $node->data;
 142              // (note $node->tagname is already normalized)
 143              if ($last instanceof HTMLPurifier_Token_Start && ($last->name == 'script' || $last->name == 'style')) {
 144                  $new_data = trim($data);
 145                  if (substr($new_data, 0, 4) === '<!--') {
 146                      $data = substr($new_data, 4);
 147                      if (substr($data, -3) === '-->') {
 148                          $data = substr($data, 0, -3);
 149                      } else {
 150                          // Highly suspicious! Not sure what to do...
 151                      }
 152                  }
 153              }
 154              $tokens[] = $this->factory->createText($this->parseData($data));
 155              return false;
 156          } elseif ($node->nodeType === XML_COMMENT_NODE) {
 157              // this is code is only invoked for comments in script/style in versions
 158              // of libxml pre-2.6.28 (regular comments, of course, are still
 159              // handled regularly)
 160              $tokens[] = $this->factory->createComment($node->data);
 161              return false;
 162          } elseif ($node->nodeType !== XML_ELEMENT_NODE) {
 163              // not-well tested: there may be other nodes we have to grab
 164              return false;
 165          }
 166  
 167          $attr = $node->hasAttributes() ? $this->transformAttrToAssoc($node->attributes) : array();
 168  
 169          // We still have to make sure that the element actually IS empty
 170          if (!$node->childNodes->length) {
 171              if ($collect) {
 172                  $tokens[] = $this->factory->createEmpty($node->tagName, $attr);
 173              }
 174              return false;
 175          } else {
 176              if ($collect) {
 177                  $tokens[] = $this->factory->createStart(
 178                      $tag_name = $node->tagName, // somehow, it get's dropped
 179                      $attr
 180                  );
 181              }
 182              return true;
 183          }
 184      }
 185  
 186      /**
 187       * @param DOMNode $node
 188       * @param HTMLPurifier_Token[] $tokens
 189       */
 190      protected function createEndNode($node, &$tokens)
 191      {
 192          $tokens[] = $this->factory->createEnd($node->tagName);
 193      }
 194  
 195  
 196      /**
 197       * Converts a DOMNamedNodeMap of DOMAttr objects into an assoc array.
 198       *
 199       * @param DOMNamedNodeMap $node_map DOMNamedNodeMap of DOMAttr objects.
 200       * @return array Associative array of attributes.
 201       */
 202      protected function transformAttrToAssoc($node_map)
 203      {
 204          // NamedNodeMap is documented very well, so we're using undocumented
 205          // features, namely, the fact that it implements Iterator and
 206          // has a ->length attribute
 207          if ($node_map->length === 0) {
 208              return array();
 209          }
 210          $array = array();
 211          foreach ($node_map as $attr) {
 212              $array[$attr->name] = $attr->value;
 213          }
 214          return $array;
 215      }
 216  
 217      /**
 218       * An error handler that mutes all errors
 219       * @param int $errno
 220       * @param string $errstr
 221       */
 222      public function muteErrorHandler($errno, $errstr)
 223      {
 224      }
 225  
 226      /**
 227       * Callback function for undoing escaping of stray angled brackets
 228       * in comments
 229       * @param array $matches
 230       * @return string
 231       */
 232      public function callbackUndoCommentSubst($matches)
 233      {
 234          return '<!--' . strtr($matches[1], array('&amp;' => '&', '&lt;' => '<')) . $matches[2];
 235      }
 236  
 237      /**
 238       * Callback function that entity-izes ampersands in comments so that
 239       * callbackUndoCommentSubst doesn't clobber them
 240       * @param array $matches
 241       * @return string
 242       */
 243      public function callbackArmorCommentEntities($matches)
 244      {
 245          return '<!--' . str_replace('&', '&amp;', $matches[1]) . $matches[2];
 246      }
 247  
 248      /**
 249       * Wraps an HTML fragment in the necessary HTML
 250       * @param string $html
 251       * @param HTMLPurifier_Config $config
 252       * @param HTMLPurifier_Context $context
 253       * @return string
 254       */
 255      protected function wrapHTML($html, $config, $context)
 256      {
 257          $def = $config->getDefinition('HTML');
 258          $ret = '';
 259  
 260          if (!empty($def->doctype->dtdPublic) || !empty($def->doctype->dtdSystem)) {
 261              $ret .= '<!DOCTYPE html ';
 262              if (!empty($def->doctype->dtdPublic)) {
 263                  $ret .= 'PUBLIC "' . $def->doctype->dtdPublic . '" ';
 264              }
 265              if (!empty($def->doctype->dtdSystem)) {
 266                  $ret .= '"' . $def->doctype->dtdSystem . '" ';
 267              }
 268              $ret .= '>';
 269          }
 270  
 271          $ret .= '<html><head>';
 272          $ret .= '<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />';
 273          // No protection if $html contains a stray </div>!
 274          $ret .= '</head><body>' . $html . '</body></html>';
 275          return $ret;
 276      }
 277  }
 278  
 279  // vim: et sw=4 sts=4
PHP Cross Reference of Unnamed Project

/lib/htmlpurifier/HTMLPurifier/Lexer/ -> DOMLex.php (source)
