library/HTMLPurifier/URIFilter/MakeAbsolute.php

   1 <?php
   2
   3 // does not support network paths
   4
   5 class HTMLPurifier_URIFilter_MakeAbsolute extends HTMLPurifier_URIFilter
   6 {
   7     /**
   8      * @type string
   9      */
  10     public $name = 'MakeAbsolute';
  11
  12     /**
  13      * @type
  14      */
  15     protected $base;
  16
  17     /**
  18      * @type array
  19      */
  20     protected $basePathStack = array();
  21
  22     /**
  23      * @param HTMLPurifier_Config $config
  24      * @return bool
  25      */
  26     public function prepare($config)
  27     {
  28         $def = $config->getDefinition('URI');
  29         $this->base = $def->base;
  30         if (is_null($this->base)) {
  31             trigger_error(
  32                 'URI.MakeAbsolute is being ignored due to lack of ' .
  33                 'value for URI.Base configuration',
  34                 E_USER_WARNING
  35             );
  36             return false;
  37         }
  38         $this->base->fragment = null; // fragment is invalid for base URI
  39         $stack = explode('/', $this->base->path);
  40         array_pop($stack); // discard last segment
  41         $stack = $this->_collapseStack($stack); // do pre-parsing
  42         $this->basePathStack = $stack;
  43         return true;
  44     }
  45
  46     /**
  47      * @param HTMLPurifier_URI $uri
  48      * @param HTMLPurifier_Config $config
  49      * @param HTMLPurifier_Context $context
  50      * @return bool
  51      */
  52     public function filter(&$uri, $config, $context)
  53     {
  54         if (is_null($this->base)) {
  55             return true;
  56         } // abort early
  57         if ($uri->path === '' && is_null($uri->scheme) &&
  58             is_null($uri->host) && is_null($uri->query) && is_null($uri->fragment)) {
  59             // reference to current document
  60             $uri = clone $this->base;
  61             return true;
  62         }
  63         if (!is_null($uri->scheme)) {
  64             // absolute URI already: don't change
  65             if (!is_null($uri->host)) {
  66                 return true;
  67             }
  68             $scheme_obj = $uri->getSchemeObj($config, $context);
  69             if (!$scheme_obj) {
  70                 // scheme not recognized
  71                 return false;
  72             }
  73             if (!$scheme_obj->hierarchical) {
  74                 // non-hierarchal URI with explicit scheme, don't change
  75                 return true;
  76             }
  77             // special case: had a scheme but always is hierarchical and had no authority
  78         }
  79         if (!is_null($uri->host)) {
  80             // network path, don't bother
  81             return true;
  82         }
  83         if ($uri->path === '') {
  84             $uri->path = $this->base->path;
  85         } elseif ($uri->path[0] !== '/') {
  86             // relative path, needs more complicated processing
  87             $stack = explode('/', $uri->path);
  88             $new_stack = array_merge($this->basePathStack, $stack);
  89             if ($new_stack[0] !== '' && !is_null($this->base->host)) {
  90                 array_unshift($new_stack, '');
  91             }
  92             $new_stack = $this->_collapseStack($new_stack);
  93             $uri->path = implode('/', $new_stack);
  94         } else {
  95             // absolute path, but still we should collapse
  96             $uri->path = implode('/', $this->_collapseStack(explode('/', $uri->path)));
  97         }
  98         // re-combine
  99         $uri->scheme = $this->base->scheme;
 100         if (is_null($uri->userinfo)) {
 101             $uri->userinfo = $this->base->userinfo;
 102         }
 103         if (is_null($uri->host)) {
 104             $uri->host = $this->base->host;
 105         }
 106         if (is_null($uri->port)) {
 107             $uri->port = $this->base->port;
 108         }
 109         return true;
 110     }
 111
 112     /**
 113      * Resolve dots and double-dots in a path stack
 114      * @param array $stack
 115      * @return array
 116      */
 117     private function _collapseStack($stack)
 118     {
 119         $result = array();
 120         $is_folder = false;
 121         for ($i = 0; isset($stack[$i]); $i++) {
 122             $is_folder = false;
 123             // absorb an internally duplicated slash
 124             if ($stack[$i] == '' && $i && isset($stack[$i + 1])) {
 125                 continue;
 126             }
 127             if ($stack[$i] == '..') {
 128                 if (!empty($result)) {
 129                     $segment = array_pop($result);
 130                     if ($segment === '' && empty($result)) {
 131                         // error case: attempted to back out too far:
 132                         // restore the leading slash
 133                         $result[] = '';
 134                     } elseif ($segment === '..') {
 135                         $result[] = '..'; // cannot remove .. with ..
 136                     }
 137                 } else {
 138                     // relative path, preserve the double-dots
 139                     $result[] = '..';
 140                 }
 141                 $is_folder = true;
 142                 continue;
 143             }
 144             if ($stack[$i] == '.') {
 145                 // silently absorb
 146                 $is_folder = true;
 147                 continue;
 148             }
 149             $result[] = $stack[$i];
 150         }
 151         if ($is_folder) {
 152             $result[] = '';
 153         }
 154         return $result;
 155     }
 156 }
 157
 158 // vim: et sw=4 sts=4