HTMLPurifier.php

<?php

/*! @mainpage
 *
 * HTML Purifier is an HTML filter that will take an arbitrary snippet of
 * HTML and rigorously test, validate and filter it into a version that
 * is safe for output onto webpages. It achieves this by:
 *
 *  -# Lexing (parsing into tokens) the document,
 *  -# Executing various strategies on the tokens:
 *      -# Removing all elements not in the whitelist,
 *      -# Making the tokens well-formed,
 *      -# Fixing the nesting of the nodes, and
 *      -# Validating attributes of the nodes; and
 *  -# Generating HTML from the purified tokens.
 *
 * However, most users will only need to interface with the HTMLPurifier
 * and HTMLPurifier_Config.
 */

/*
    HTML Purifier 4.0.0 - Standards Compliant HTML Filtering
    Copyright (C) 2006-2008 Edward Z. Yang

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

/**
 * Facade that coordinates HTML Purifier's subsystems in order to purify HTML.
 *
 * @note There are several points in which configuration can be specified
 *       for HTML Purifier.  The precedence of these (from lowest to
 *       highest) is as follows:
 *          -# Instance: new HTMLPurifier($config)
 *          -# Invocation: purify($html, $config)
 *       These configurations are entirely independent of each other and
 *       are *not* merged (this behavior may change in the future).
 *
 * @todo We need an easier way to inject strategies using the configuration
 *       object.
 */
class HTMLPurifier
{

    /** Version of HTML Purifier */
    public $version = '4.0.0';

    /** Constant with version of HTML Purifier */
    const VERSION = '4.0.0';

    /** Global configuration object */
    public $config;

    /** Array of extra HTMLPurifier_Filter objects to run on HTML, for backwards compatibility */
    private $filters = array();

    /** Single instance of HTML Purifier */
    private static $instance;