library/HTMLPurifier/URIFilter.php

   1 <?php
   2
   3 /**
   4  * Chainable filters for custom URI processing.
   5  *
   6  * These filters can perform custom actions on a URI filter object,
   7  * including transformation or blacklisting.  A filter named Foo
   8  * must have a corresponding configuration directive %URI.Foo,
   9  * unless always_load is specified to be true.
  10  *
  11  * The following contexts may be available while URIFilters are being
  12  * processed:
  13  *
  14  *      - EmbeddedURI: true if URI is an embedded resource that will
  15  *        be loaded automatically on page load
  16  *      - CurrentToken: a reference to the token that is currently
  17  *        being processed
  18  *      - CurrentAttr: the name of the attribute that is currently being
  19  *        processed
  20  *      - CurrentCSSProperty: the name of the CSS property that is
  21  *        currently being processed (if applicable)
  22  *
  23  * @warning This filter is called before scheme object validation occurs.
  24  *          Make sure, if you require a specific scheme object, you
  25  *          you check that it exists. This allows filters to convert
  26  *          proprietary URI schemes into regular ones.
  27  */
  28 abstract class HTMLPurifier_URIFilter
  29 {
  30
  31     /**
  32      * Unique identifier of filter.
  33      * @type string
  34      */
  35     public $name;
  36
  37     /**
  38      * True if this filter should be run after scheme validation.
  39      * @type bool
  40      */
  41     public $post = false;
  42
  43     /**
  44      * True if this filter should always be loaded.
  45      * This permits a filter to be named Foo without the corresponding
  46      * %URI.Foo directive existing.
  47      * @type bool
  48      */
  49     public $always_load = false;
  50
  51     /**
  52      * Performs initialization for the filter.  If the filter returns
  53      * false, this means that it shouldn't be considered active.
  54      * @param HTMLPurifier_Config $config
  55      * @return bool
  56      */
  57     public function prepare($config)
  58     {
  59         return true;
  60     }
  61
  62     /**
  63      * Filter a URI object
  64      * @param HTMLPurifier_URI $uri Reference to URI object variable
  65      * @param HTMLPurifier_Config $config
  66      * @param HTMLPurifier_Context $context
  67      * @return bool Whether or not to continue processing: false indicates
  68      *         URL is no good, true indicates continue processing. Note that
  69      *         all changes are committed directly on the URI object
  70      */
  71     abstract public function filter(&$uri, $config, $context);
  72 }
  73
  74 // vim: et sw=4 sts=4