library/HTMLPurifier/Lexer/PEARSax3.php

   1 <?php
   2
   3 /**
   4  * Proof-of-concept lexer that uses the PEAR package XML_HTMLSax3 to parse HTML.
   5  *
   6  * PEAR, not suprisingly, also has a SAX parser for HTML.  I don't know
   7  * very much about implementation, but it's fairly well written.  However, that
   8  * abstraction comes at a price: performance. You need to have it installed,
   9  * and if the API changes, it might break our adapter. Not sure whether or not
  10  * it's UTF-8 aware, but it has some entity parsing trouble (in all areas,
  11  * text and attributes).
  12  *
  13  * Quite personally, I don't recommend using the PEAR class, and the defaults
  14  * don't use it. The unit tests do perform the tests on the SAX parser too, but
  15  * whatever it does for poorly formed HTML is up to it.
  16  *
  17  * @todo Generalize so that XML_HTMLSax is also supported.
  18  *
  19  * @warning Entity-resolution inside attributes is broken.
  20  */
  21
  22 class HTMLPurifier_Lexer_PEARSax3 extends HTMLPurifier_Lexer
  23 {
  24
  25     /**
  26      * Internal accumulator array for SAX parsers.
  27      */
  28     protected $tokens = array();
  29
  30     public function tokenizeHTML($string, $config, $context) {
  31
  32         $this->tokens = array();
  33
  34         $string = $this->normalize($string, $config, $context);
  35
  36         $parser = new XML_HTMLSax3();
  37         $parser->set_object($this);
  38         $parser->set_element_handler('openHandler','closeHandler');
  39         $parser->set_data_handler('dataHandler');
  40         $parser->set_escape_handler('escapeHandler');
  41
  42         // doesn't seem to work correctly for attributes
  43         $parser->set_option('XML_OPTION_ENTITIES_PARSED', 1);
  44
  45         $parser->parse($string);
  46
  47         return $this->tokens;
  48
  49     }
  50
  51     /**
  52      * Open tag event handler, interface is defined by PEAR package.
  53      */
  54     public function openHandler(&$parser, $name, $attrs, $closed) {
  55         // entities are not resolved in attrs
  56         foreach ($attrs as $key => $attr) {
  57             $attrs[$key] = $this->parseData($attr);
  58         }
  59         if ($closed) {
  60             $this->tokens[] = new HTMLPurifier_Token_Empty($name, $attrs);
  61         } else {
  62             $this->tokens[] = new HTMLPurifier_Token_Start($name, $attrs);
  63         }
  64         return true;
  65     }
  66
  67     /**
  68      * Close tag event handler, interface is defined by PEAR package.
  69      */
  70     public function closeHandler(&$parser, $name) {
  71         // HTMLSax3 seems to always send empty tags an extra close tag
  72         // check and ignore if you see it:
  73         // [TESTME] to make sure it doesn't overreach
  74         if ($this->tokens[count($this->tokens)-1] instanceof HTMLPurifier_Token_Empty) {
  75             return true;
  76         }
  77         $this->tokens[] = new HTMLPurifier_Token_End($name);
  78         return true;
  79     }
  80
  81     /**
  82      * Data event handler, interface is defined by PEAR package.
  83      */
  84     public function dataHandler(&$parser, $data) {
  85         $this->tokens[] = new HTMLPurifier_Token_Text($data);
  86         return true;
  87     }
  88
  89     /**
  90      * Escaped text handler, interface is defined by PEAR package.
  91      */
  92     public function escapeHandler(&$parser, $data) {
  93         if (strpos($data, '--') === 0) {
  94             $this->tokens[] = new HTMLPurifier_Token_Comment($data);
  95         }
  96         // CDATA is handled elsewhere, but if it was handled here:
  97         //if (strpos($data, '[CDATA[') === 0) {
  98         //    $this->tokens[] = new HTMLPurifier_Token_Text(
  99         //        substr($data, 7, strlen($data) - 9) );
 100         //}
 101         return true;
 102     }
 103
 104 }
 105
 106 // vim: et sw=4 sts=4