library/HTMLPurifier/AttrDef/CSS/Filter.php

   1 <?php
   2
   3 /**
   4  * Microsoft's proprietary filter: CSS property
   5  * @note Currently supports the alpha filter. In the future, this will
   6  *       probably need an extensible framework
   7  */
   8 class HTMLPurifier_AttrDef_CSS_Filter extends HTMLPurifier_AttrDef
   9 {
  10     /**
  11      * @type HTMLPurifier_AttrDef_Integer
  12      */
  13     protected $intValidator;
  14
  15     public function __construct()
  16     {
  17         $this->intValidator = new HTMLPurifier_AttrDef_Integer();
  18     }
  19
  20     /**
  21      * @param string $value
  22      * @param HTMLPurifier_Config $config
  23      * @param HTMLPurifier_Context $context
  24      * @return bool|string
  25      */
  26     public function validate($value, $config, $context)
  27     {
  28         $value = $this->parseCDATA($value);
  29         if ($value === 'none') {
  30             return $value;
  31         }
  32         // if we looped this we could support multiple filters
  33         $function_length = strcspn($value, '(');
  34         $function = trim(substr($value, 0, $function_length));
  35         if ($function !== 'alpha' &&
  36             $function !== 'Alpha' &&
  37             $function !== 'progid:DXImageTransform.Microsoft.Alpha'
  38         ) {
  39             return false;
  40         }
  41         $cursor = $function_length + 1;
  42         $parameters_length = strcspn($value, ')', $cursor);
  43         $parameters = substr($value, $cursor, $parameters_length);
  44         $params = explode(',', $parameters);
  45         $ret_params = array();
  46         $lookup = array();
  47         foreach ($params as $param) {
  48             list($key, $value) = explode('=', $param);
  49             $key = trim($key);
  50             $value = trim($value);
  51             if (isset($lookup[$key])) {
  52                 continue;
  53             }
  54             if ($key !== 'opacity') {
  55                 continue;
  56             }
  57             $value = $this->intValidator->validate($value, $config, $context);
  58             if ($value === false) {
  59                 continue;
  60             }
  61             $int = (int)$value;
  62             if ($int > 100) {
  63                 $value = '100';
  64             }
  65             if ($int < 0) {
  66                 $value = '0';
  67             }
  68             $ret_params[] = "$key=$value";
  69             $lookup[$key] = true;
  70         }
  71         $ret_parameters = implode(',', $ret_params);
  72         $ret_function = "$function($ret_parameters)";
  73         return $ret_function;
  74     }
  75 }
  76
  77 // vim: et sw=4 sts=4