crm.fsf.org/20131203/files/sites/all/modules-old/civicrm/packages/IDS/vendors/htmlpurifier/HTMLPurifier/ConfigSchema/schema/Filter.ExtractStyleBlocks.txt

   1 Filter.ExtractStyleBlocks
   2 TYPE: bool
   3 VERSION: 3.1.0
   4 DEFAULT: false
   5 EXTERNAL: CSSTidy
   6 --DESCRIPTION--
   7 <p>
   8   This directive turns on the style block extraction filter, which removes
   9   <code>style</code> blocks from input HTML, cleans them up with CSSTidy,
  10   and places them in the <code>StyleBlocks</code> context variable, for further
  11   use by you, usually to be placed in an external stylesheet, or a
  12   <code>style</code> block in the <code>head</code> of your document.
  13 </p>
  14 <p>
  15   Sample usage:
  16 </p>
  17 <pre><![CDATA[
  18 <?php
  19     header('Content-type: text/html; charset=utf-8');
  20     echo '<?xml version="1.0" encoding="UTF-8"?>';
  21 ?>
  22 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
  23   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
  24 <html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
  25 <head>
  26   <title>Filter.ExtractStyleBlocks</title>
  27 <?php
  28     require_once '/path/to/library/HTMLPurifier.auto.php';
  29     require_once '/path/to/csstidy.class.php';
  30
  31     $dirty = '<style>body {color:#F00;}</style> Some text';
  32
  33     $config = HTMLPurifier_Config::createDefault();
  34     $config->set('Filter', 'ExtractStyleBlocks', true);
  35     $purifier = new HTMLPurifier($config);
  36
  37     $html = $purifier->purify($dirty);
  38
  39     // This implementation writes the stylesheets to the styles/ directory.
  40     // You can also echo the styles inside the document, but it's a bit
  41     // more difficult to make sure they get interpreted properly by
  42     // browsers; try the usual CSS armoring techniques.
  43     $styles = $purifier->context->get('StyleBlocks');
  44     $dir = 'styles/';
  45     if (!is_dir($dir)) mkdir($dir);
  46     $hash = sha1($_GET['html']);
  47     foreach ($styles as $i => $style) {
  48         file_put_contents($name = $dir . $hash . "_$i");
  49         echo '<link rel="stylesheet" type="text/css" href="'.$name.'" />';
  50     }
  51 ?>
  52 </head>
  53 <body>
  54   <div>
  55     <?php echo $html; ?>
  56   </div>
  57 </b]]><![CDATA[ody>
  58 </html>
  59 ]]></pre>
  60 <p>
  61   <strong>Warning:</strong> It is possible for a user to mount an
  62   imagecrash attack using this CSS. Counter-measures are difficult;
  63   it is not simply enough to limit the range of CSS lengths (using
  64   relative lengths with many nesting levels allows for large values
  65   to be attained without actually specifying them in the stylesheet),
  66   and the flexible nature of selectors makes it difficult to selectively
  67   disable lengths on image tags (HTML Purifier, however, does disable
  68   CSS width and height in inline styling). There are probably two effective
  69   counter measures: an explicit width and height set to auto in all
  70   images in your document (unlikely) or the disabling of width and
  71   height (somewhat reasonable). Whether or not these measures should be
  72   used is left to the reader.
  73 </p>
  74 --# vim: et sw=4 sts=4