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[htmlpurifier.git] / library / HTMLPurifier.php
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1 <?php
3 /*! @mainpage
5 * HTML Purifier is an HTML filter that will take an arbitrary snippet of
6 * HTML and rigorously test, validate and filter it into a version that
7 * is safe for output onto webpages. It achieves this by:
9 * -# Lexing (parsing into tokens) the document,
10 * -# Executing various strategies on the tokens:
11 * -# Removing all elements not in the whitelist,
12 * -# Making the tokens well-formed,
13 * -# Fixing the nesting of the nodes, and
14 * -# Validating attributes of the nodes; and
15 * -# Generating HTML from the purified tokens.
17 * However, most users will only need to interface with the HTMLPurifier
18 * and HTMLPurifier_Config.
22 HTML Purifier 4.10.0 - Standards Compliant HTML Filtering
23 Copyright (C) 2006-2008 Edward Z. Yang
25 This library is free software; you can redistribute it and/or
26 modify it under the terms of the GNU Lesser General Public
27 License as published by the Free Software Foundation; either
28 version 2.1 of the License, or (at your option) any later version.
30 This library is distributed in the hope that it will be useful,
31 but WITHOUT ANY WARRANTY; without even the implied warranty of
32 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
33 Lesser General Public License for more details.
35 You should have received a copy of the GNU Lesser General Public
36 License along with this library; if not, write to the Free Software
37 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
40 /**
41 * Facade that coordinates HTML Purifier's subsystems in order to purify HTML.
43 * @note There are several points in which configuration can be specified
44 * for HTML Purifier. The precedence of these (from lowest to
45 * highest) is as follows:
46 * -# Instance: new HTMLPurifier($config)
47 * -# Invocation: purify($html, $config)
48 * These configurations are entirely independent of each other and
49 * are *not* merged (this behavior may change in the future).
51 * @todo We need an easier way to inject strategies using the configuration
52 * object.
54 class HTMLPurifier
57 /**
58 * Version of HTML Purifier.
59 * @type string
61 public $version = '4.10.0';
63 /**
64 * Constant with version of HTML Purifier.
66 const VERSION = '4.10.0';
68 /**
69 * Global configuration object.
70 * @type HTMLPurifier_Config
72 public $config;
74 /**
75 * Array of extra filter objects to run on HTML,
76 * for backwards compatibility.
77 * @type HTMLPurifier_Filter[]
79 private $filters = array();
81 /**
82 * Single instance of HTML Purifier.
83 * @type HTMLPurifier
85 private static $instance;
87 /**
88 * @type HTMLPurifier_Strategy_Core
90 protected $strategy;
92 /**
93 * @type HTMLPurifier_Generator
95 protected $generator;
97 /**
98 * Resultant context of last run purification.
99 * Is an array of contexts if the last called method was purifyArray().
100 * @type HTMLPurifier_Context
102 public $context;
105 * Initializes the purifier.
107 * @param HTMLPurifier_Config|mixed $config Optional HTMLPurifier_Config object
108 * for all instances of the purifier, if omitted, a default
109 * configuration is supplied (which can be overridden on a
110 * per-use basis).
111 * The parameter can also be any type that
112 * HTMLPurifier_Config::create() supports.
114 public function __construct($config = null)
116 $this->config = HTMLPurifier_Config::create($config);
117 $this->strategy = new HTMLPurifier_Strategy_Core();
121 * Adds a filter to process the output. First come first serve
123 * @param HTMLPurifier_Filter $filter HTMLPurifier_Filter object
125 public function addFilter($filter)
127 trigger_error(
128 'HTMLPurifier->addFilter() is deprecated, use configuration directives' .
129 ' in the Filter namespace or Filter.Custom',
130 E_USER_WARNING
132 $this->filters[] = $filter;
136 * Filters an HTML snippet/document to be XSS-free and standards-compliant.
138 * @param string $html String of HTML to purify
139 * @param HTMLPurifier_Config $config Config object for this operation,
140 * if omitted, defaults to the config object specified during this
141 * object's construction. The parameter can also be any type
142 * that HTMLPurifier_Config::create() supports.
144 * @return string Purified HTML
146 public function purify($html, $config = null)
148 // :TODO: make the config merge in, instead of replace
149 $config = $config ? HTMLPurifier_Config::create($config) : $this->config;
151 // implementation is partially environment dependant, partially
152 // configuration dependant
153 $lexer = HTMLPurifier_Lexer::create($config);
155 $context = new HTMLPurifier_Context();
157 // setup HTML generator
158 $this->generator = new HTMLPurifier_Generator($config, $context);
159 $context->register('Generator', $this->generator);
161 // set up global context variables
162 if ($config->get('Core.CollectErrors')) {
163 // may get moved out if other facilities use it
164 $language_factory = HTMLPurifier_LanguageFactory::instance();
165 $language = $language_factory->create($config, $context);
166 $context->register('Locale', $language);
168 $error_collector = new HTMLPurifier_ErrorCollector($context);
169 $context->register('ErrorCollector', $error_collector);
172 // setup id_accumulator context, necessary due to the fact that
173 // AttrValidator can be called from many places
174 $id_accumulator = HTMLPurifier_IDAccumulator::build($config, $context);
175 $context->register('IDAccumulator', $id_accumulator);
177 $html = HTMLPurifier_Encoder::convertToUTF8($html, $config, $context);
179 // setup filters
180 $filter_flags = $config->getBatch('Filter');
181 $custom_filters = $filter_flags['Custom'];
182 unset($filter_flags['Custom']);
183 $filters = array();
184 foreach ($filter_flags as $filter => $flag) {
185 if (!$flag) {
186 continue;
188 if (strpos($filter, '.') !== false) {
189 continue;
191 $class = "HTMLPurifier_Filter_$filter";
192 $filters[] = new $class;
194 foreach ($custom_filters as $filter) {
195 // maybe "HTMLPurifier_Filter_$filter", but be consistent with AutoFormat
196 $filters[] = $filter;
198 $filters = array_merge($filters, $this->filters);
199 // maybe prepare(), but later
201 for ($i = 0, $filter_size = count($filters); $i < $filter_size; $i++) {
202 $html = $filters[$i]->preFilter($html, $config, $context);
205 // purified HTML
206 $html =
207 $this->generator->generateFromTokens(
208 // list of tokens
209 $this->strategy->execute(
210 // list of un-purified tokens
211 $lexer->tokenizeHTML(
212 // un-purified HTML
213 $html,
214 $config,
215 $context
217 $config,
218 $context
222 for ($i = $filter_size - 1; $i >= 0; $i--) {
223 $html = $filters[$i]->postFilter($html, $config, $context);
226 $html = HTMLPurifier_Encoder::convertFromUTF8($html, $config, $context);
227 $this->context =& $context;
228 return $html;
232 * Filters an array of HTML snippets
234 * @param string[] $array_of_html Array of html snippets
235 * @param HTMLPurifier_Config $config Optional config object for this operation.
236 * See HTMLPurifier::purify() for more details.
238 * @return string[] Array of purified HTML
240 public function purifyArray($array_of_html, $config = null)
242 $context_array = array();
243 foreach ($array_of_html as $key => $html) {
244 $array_of_html[$key] = $this->purify($html, $config);
245 $context_array[$key] = $this->context;
247 $this->context = $context_array;
248 return $array_of_html;
252 * Singleton for enforcing just one HTML Purifier in your system
254 * @param HTMLPurifier|HTMLPurifier_Config $prototype Optional prototype
255 * HTMLPurifier instance to overload singleton with,
256 * or HTMLPurifier_Config instance to configure the
257 * generated version with.
259 * @return HTMLPurifier
261 public static function instance($prototype = null)
263 if (!self::$instance || $prototype) {
264 if ($prototype instanceof HTMLPurifier) {
265 self::$instance = $prototype;
266 } elseif ($prototype) {
267 self::$instance = new HTMLPurifier($prototype);
268 } else {
269 self::$instance = new HTMLPurifier();
272 return self::$instance;
276 * Singleton for enforcing just one HTML Purifier in your system
278 * @param HTMLPurifier|HTMLPurifier_Config $prototype Optional prototype
279 * HTMLPurifier instance to overload singleton with,
280 * or HTMLPurifier_Config instance to configure the
281 * generated version with.
283 * @return HTMLPurifier
284 * @note Backwards compatibility, see instance()
286 public static function getInstance($prototype = null)
288 return HTMLPurifier::instance($prototype);
292 // vim: et sw=4 sts=4