Evan Prodromou 81ea0f8117 Add HTMLPurifier to extlib
HTMLPurifier defangs arbitrary submitted HTML. We're using it in the
OStatus plugin, but it may be valuable for other parts of the codebase
(I think OEmbed might benefit, for example).
2010-02-20 11:35:01 -05:00

184 lines
6.4 KiB
PHP

<?php
/**
* Generates HTML from tokens.
* @todo Refactor interface so that configuration/context is determined
* upon instantiation, no need for messy generateFromTokens() calls
* @todo Make some of the more internal functions protected, and have
* unit tests work around that
*/
class HTMLPurifier_Generator
{
/**
* Whether or not generator should produce XML output
*/
private $_xhtml = true;
/**
* :HACK: Whether or not generator should comment the insides of <script> tags
*/
private $_scriptFix = false;
/**
* Cache of HTMLDefinition during HTML output to determine whether or
* not attributes should be minimized.
*/
private $_def;
/**
* Cache of %Output.SortAttr
*/
private $_sortAttr;
/**
* Configuration for the generator
*/
protected $config;
/**
* @param $config Instance of HTMLPurifier_Config
* @param $context Instance of HTMLPurifier_Context
*/
public function __construct($config, $context) {
$this->config = $config;
$this->_scriptFix = $config->get('Output.CommentScriptContents');
$this->_sortAttr = $config->get('Output.SortAttr');
$this->_def = $config->getHTMLDefinition();
$this->_xhtml = $this->_def->doctype->xml;
}
/**
* Generates HTML from an array of tokens.
* @param $tokens Array of HTMLPurifier_Token
* @param $config HTMLPurifier_Config object
* @return Generated HTML
*/
public function generateFromTokens($tokens) {
if (!$tokens) return '';
// Basic algorithm
$html = '';
for ($i = 0, $size = count($tokens); $i < $size; $i++) {
if ($this->_scriptFix && $tokens[$i]->name === 'script'
&& $i + 2 < $size && $tokens[$i+2] instanceof HTMLPurifier_Token_End) {
// script special case
// the contents of the script block must be ONE token
// for this to work.
$html .= $this->generateFromToken($tokens[$i++]);
$html .= $this->generateScriptFromToken($tokens[$i++]);
}
$html .= $this->generateFromToken($tokens[$i]);
}
// Tidy cleanup
if (extension_loaded('tidy') && $this->config->get('Output.TidyFormat')) {
$tidy = new Tidy;
$tidy->parseString($html, array(
'indent'=> true,
'output-xhtml' => $this->_xhtml,
'show-body-only' => true,
'indent-spaces' => 2,
'wrap' => 68,
), 'utf8');
$tidy->cleanRepair();
$html = (string) $tidy; // explicit cast necessary
}
// Normalize newlines to system defined value
$nl = $this->config->get('Output.Newline');
if ($nl === null) $nl = PHP_EOL;
if ($nl !== "\n") $html = str_replace("\n", $nl, $html);
return $html;
}
/**
* Generates HTML from a single token.
* @param $token HTMLPurifier_Token object.
* @return Generated HTML
*/
public function generateFromToken($token) {
if (!$token instanceof HTMLPurifier_Token) {
trigger_error('Cannot generate HTML from non-HTMLPurifier_Token object', E_USER_WARNING);
return '';
} elseif ($token instanceof HTMLPurifier_Token_Start) {
$attr = $this->generateAttributes($token->attr, $token->name);
return '<' . $token->name . ($attr ? ' ' : '') . $attr . '>';
} elseif ($token instanceof HTMLPurifier_Token_End) {
return '</' . $token->name . '>';
} elseif ($token instanceof HTMLPurifier_Token_Empty) {
$attr = $this->generateAttributes($token->attr, $token->name);
return '<' . $token->name . ($attr ? ' ' : '') . $attr .
( $this->_xhtml ? ' /': '' ) // <br /> v. <br>
. '>';
} elseif ($token instanceof HTMLPurifier_Token_Text) {
return $this->escape($token->data, ENT_NOQUOTES);
} elseif ($token instanceof HTMLPurifier_Token_Comment) {
return '<!--' . $token->data . '-->';
} else {
return '';
}
}
/**
* Special case processor for the contents of script tags
* @warning This runs into problems if there's already a literal
* --> somewhere inside the script contents.
*/
public function generateScriptFromToken($token) {
if (!$token instanceof HTMLPurifier_Token_Text) return $this->generateFromToken($token);
// Thanks <http://lachy.id.au/log/2005/05/script-comments>
$data = preg_replace('#//\s*$#', '', $token->data);
return '<!--//--><![CDATA[//><!--' . "\n" . trim($data) . "\n" . '//--><!]]>';
}
/**
* Generates attribute declarations from attribute array.
* @note This does not include the leading or trailing space.
* @param $assoc_array_of_attributes Attribute array
* @param $element Name of element attributes are for, used to check
* attribute minimization.
* @return Generate HTML fragment for insertion.
*/
public function generateAttributes($assoc_array_of_attributes, $element = false) {
$html = '';
if ($this->_sortAttr) ksort($assoc_array_of_attributes);
foreach ($assoc_array_of_attributes as $key => $value) {
if (!$this->_xhtml) {
// Remove namespaced attributes
if (strpos($key, ':') !== false) continue;
// Check if we should minimize the attribute: val="val" -> val
if ($element && !empty($this->_def->info[$element]->attr[$key]->minimized)) {
$html .= $key . ' ';
continue;
}
}
$html .= $key.'="'.$this->escape($value).'" ';
}
return rtrim($html);
}
/**
* Escapes raw text data.
* @todo This really ought to be protected, but until we have a facility
* for properly generating HTML here w/o using tokens, it stays
* public.
* @param $string String data to escape for HTML.
* @param $quote Quoting style, like htmlspecialchars. ENT_NOQUOTES is
* permissible for non-attribute output.
* @return String escaped data.
*/
public function escape($string, $quote = ENT_COMPAT) {
return htmlspecialchars($string, $quote, 'UTF-8');
}
}
// vim: et sw=4 sts=4