[Summary view]

   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