library/HTMLPurifier/URISchemeRegistry.php

   1 <?php
   2
   3 /**
   4  * Registry for retrieving specific URI scheme validator objects.
   5  */
   6 class HTMLPurifier_URISchemeRegistry
   7 {
   8
   9     /**
  10      * Retrieve sole instance of the registry.
  11      * @param HTMLPurifier_URISchemeRegistry $prototype Optional prototype to overload sole instance with,
  12      *                   or bool true to reset to default registry.
  13      * @return HTMLPurifier_URISchemeRegistry
  14      * @note Pass a registry object $prototype with a compatible interface and
  15      *       the function will copy it and return it all further times.
  16      */
  17     public static function instance($prototype = null)
  18     {
  19         static $instance = null;
  20         if ($prototype !== null) {
  21             $instance = $prototype;
  22         } elseif ($instance === null || $prototype == true) {
  23             $instance = new HTMLPurifier_URISchemeRegistry();
  24         }
  25         return $instance;
  26     }
  27
  28     /**
  29      * Cache of retrieved schemes.
  30      * @type HTMLPurifier_URIScheme[]
  31      */
  32     protected $schemes = array();
  33
  34     /**
  35      * Retrieves a scheme validator object
  36      * @param string $scheme String scheme name like http or mailto
  37      * @param HTMLPurifier_Config $config
  38      * @param HTMLPurifier_Context $context
  39      * @return HTMLPurifier_URIScheme
  40      */
  41     public function getScheme($scheme, $config, $context)
  42     {
  43         if (!$config) {
  44             $config = HTMLPurifier_Config::createDefault();
  45         }
  46
  47         // important, otherwise attacker could include arbitrary file
  48         $allowed_schemes = $config->get('URI.AllowedSchemes');
  49         if (!$config->get('URI.OverrideAllowedSchemes') &&
  50             !isset($allowed_schemes[$scheme])
  51         ) {
  52             return;
  53         }
  54
  55         if (isset($this->schemes[$scheme])) {
  56             return $this->schemes[$scheme];
  57         }
  58         if (!isset($allowed_schemes[$scheme])) {
  59             return;
  60         }
  61
  62         $class = 'HTMLPurifier_URIScheme_' . $scheme;
  63         if (!class_exists($class)) {
  64             return;
  65         }
  66         $this->schemes[$scheme] = new $class();
  67         return $this->schemes[$scheme];
  68     }
  69
  70     /**
  71      * Registers a custom scheme to the cache, bypassing reflection.
  72      * @param string $scheme Scheme name
  73      * @param HTMLPurifier_URIScheme $scheme_obj
  74      */
  75     public function register($scheme, $scheme_obj)
  76     {
  77         $this->schemes[$scheme] = $scheme_obj;
  78     }
  79 }
  80
  81 // vim: et sw=4 sts=4