source: trunk/lib/App.inc.php @ 523

<?php
/**
 * The Strangecode Codebase - a general application development framework for PHP
 * For details visit the project site: <http://trac.strangecode.com/codebase/>
 * Copyright 2001-2012 Strangecode, LLC
 *
 * This file is part of The Strangecode Codebase.
 *
 * The Strangecode Codebase is free software: you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your option)
 * any later version.
 *
 * The Strangecode Codebase 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 General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License along with
 * The Strangecode Codebase. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * App.inc.php
 *
 * Primary application framework class.
 *
 * @author  Quinn Comendant <quinn@strangecode.com>
 * @version 2.1
 */

// Message Types.
define('MSG_ERR', 1);
define('MSG_ERROR', MSG_ERR);
define('MSG_WARNING', 2);
define('MSG_NOTICE', 4);
define('MSG_SUCCESS', 8);
define('MSG_ALL', MSG_SUCCESS | MSG_NOTICE | MSG_WARNING | MSG_ERROR);

require_once dirname(__FILE__) . '/Utilities.inc.php';

class App
{

    // Minimum version of PHP required for this version of the Codebase.
    const CODEBASE_MIN_PHP_VERSION = '5.3.0';

    // A place to keep an object instance for the singleton pattern.
    protected static $instance = null;

    // Namespace of this application instance.
    protected $_ns;

    // If $app->start has run successfully.
    public $running = false;

    // Instance of database object.
    public $db;

    // Array of query arguments will be carried persistently between requests.
    protected $_carry_queries = array();

    // Array of raised message counters.
    protected $_raised_msg_counter = array(MSG_NOTICE => 0, MSG_SUCCESS => 0, MSG_WARNING => 0, MSG_ERR => 0);

    // Dictionary of global application parameters.
    protected $_params = array();

    // Default parameters.
    protected $_param_defaults = array(

        // Public name and email address for this application.
        'site_name' => null,
        'site_email' => '', // Set to no-reply@HTTP_HOST if not set here.
        'site_url' => '', // URL automatically determined by _SERVER['HTTP_HOST'] if not set here.
        'images_path' => '', // Location for codebase-generated interface widgets (ex: "/admin/i").
        'site_version_file' => 'docs/version.txt', // File containing version number of this app, relative to the include path.

        // The location the user will go if the system doesn't know where else to send them.
        'redirect_home_url' => '/',

        // SSL URL used when redirecting with $app->sslOn().
        'ssl_domain' => null,
        'ssl_enabled' => false,

        // Use CSRF tokens. See notes in the getCSRFToken() method.
        'csrf_token_enabled' => true,
        // Form tokens will expire after this duration, in seconds.
        'csrf_token_timeout' => 259200, // 259200 seconds = 3 days.
        'csrf_token_name' => 'csrf_token',

        // HMAC signing method
        'signing_method' => 'sha512+base64',

        // Character set for page output. Used in the Content-Type header and the HTML <meta content-type> tag.
        'character_set' => 'utf-8',

        // Human-readable format used to display dates.
        'date_format' => 'd M Y',
        'time_format' => 'h:i:s A',
        'sql_date_format' => '%e %b %Y',
        'sql_time_format' => '%k:%i',

        // Use php sessions?
        'enable_session' => false,
        'session_name' => '_session',
        'session_use_cookies' => true,

        // Pass the session-id through URLs if cookies are not enabled?
        // Disable this to prevent session ID theft.
        'session_use_trans_sid' => false,

        // Use database?
        'enable_db' => false,

        // Use db-based sessions?
        'enable_db_session_handler' => false,

        // DB credentials should be set as apache environment variables in httpd.conf, readable only by root.
        'db_server' => 'localhost',
        'db_name' => null,
        'db_user' => null,
        'db_pass' => null,

        // And for CLI scripts, which should include a JSON file at this specified location in the include path.
        'db_auth_file' => 'db_auth.json',

        // Database debugging.
        'db_always_debug' => false, // TRUE = display all SQL queries.
        'db_debug' => false, // TRUE = display db errors.
        'db_die_on_failure' => false, // TRUE = script stops on db error.

        // For classes that require db tables, do we check that a table exists and create if missing?
        'db_create_tables' => true,

        // The level of error reporting. Don't change this to suppress messages, instead use display_errors to control display.
        'error_reporting' => E_ALL,

        // Don't display errors by default; it is preferable to log them to a file. For CLI scripts, set this to the string 'stderr'.
        'display_errors' => false,

        // Directory in which to store log files.
        'log_directory' => '',

        // PHP error log.
        'php_error_log' => 'php_error_log',

        // General application log.
        'log_filename' => 'app_log',

        // Don't email or SMS duplicate messages that happen more often than this value (in seconds).
        'log_multiple_timeout' => 3600, // Hourly

        // Logging priority can be any of the following, or false to deactivate:
        // LOG_EMERG     system is unusable
        // LOG_ALERT     action must be taken immediately
        // LOG_CRIT      critical conditions
        // LOG_ERR       error conditions
        // LOG_WARNING   warning conditions
        // LOG_NOTICE    normal, but significant, condition
        // LOG_INFO      informational message
        // LOG_DEBUG     debug-level message
        'log_file_priority' => LOG_INFO,
        'log_email_priority' => false,
        'log_sms_priority' => false,
        'log_screen_priority' => false,

        // Email address to receive log event emails. Use multiple addresses by separating them with commas.
        'log_to_email_address' => null,

        // SMS Email address to receive log event SMS messages. Use multiple addresses by separating them with commas.
        'log_to_sms_address' => null,

        // Should we avoid logging repeated logMsg() events? You might want to set this false if you need to see more accurate logging, particularly for long-running scripts.
        'log_ignore_repeated_events' => true,

        // Temporary files directory.
        'tmp_dir' => '/tmp',

        // A key for calculating simple cryptographic signatures. Set using as an environment variables in the httpd.conf with 'SetEnv SIGNING_KEY <key>'.
        // Existing password hashes rely on the same key/salt being used to compare encryptions.
        // Don't change this unless you know existing hashes or signatures will not be affected!
        'signing_key' => 'aae6abd6209d82a691a9f96384a7634a',

        // Force getFormData, getPost, and getGet to always run dispelMagicQuotes() with stripslashes().
        // This should be set to 'true' when using the codebase with Wordpress because
        // WP forcefully adds slashes to all input despite the setting of magic_quotes_gpc.
        'always_dispel_magicquotes' => false,
    );

    /**
     * Constructor.
     */
    public function __construct($namespace='')
    {
        // Set namespace of application instance.
        $this->_ns = $namespace;

        // Initialize default parameters.
        $this->_params = array_merge($this->_params, $this->_param_defaults);

        // Begin timing script.
        require_once dirname(__FILE__) . '/ScriptTimer.inc.php';
        $this->timer = new ScriptTimer();
        $this->timer->start('_app');
    }

    /**
     * This method enforces the singleton pattern for this class. Only one application is running at a time.
     *
     * $param   string  $namespace  Name of this application.
     * @return  object  Reference to the global Cache object.
     * @access  public
     * @static
     */
    public static function &getInstance($namespace='')
    {
        if (self::$instance === null) {
            // TODO: Yep, having a namespace with one singletone instance is not very useful.
            self::$instance = new self($namespace);
        }

        return self::$instance;
    }

    /**
     * Set (or overwrite existing) parameters by passing an array of new parameters.
     *
     * @access public
     * @param  array    $param     Array of parameters (key => val pairs).
     */
    public function setParam($param=null)
    {
        if (isset($param) && is_array($param)) {
            // Merge new parameters with old overriding old ones that are passed.
            $this->_params = array_merge($this->_params, $param);

            if ($this->running) {
                // Params that require additional processing if set during runtime.
                foreach ($param as $key => $val) {
                    switch ($key) {
                    case 'session_name':
                        session_name($val);
                        break;

                    case 'session_use_cookies':
                        ini_set('session.use_cookies', $val);
                        break;

                    case 'error_reporting':
                        ini_set('error_reporting', $val);
                        break;

                    case 'display_errors':
                        ini_set('display_errors', $val);
                        break;

                    case 'log_errors':
                        ini_set('log_errors', true);
                        break;

                    case 'log_directory':
                        if (is_dir($val) && is_writable($val)) {
                            ini_set('error_log', $val . '/' . $this->getParam('php_error_log'));
                        }
                        break;
                    }
                }
            }
        }
    }

    /**
     * Return the value of a parameter.
     *
     * @access  public
     * @param   string  $param      The key of the parameter to return.
     * @return  mixed               Parameter value, or null if not existing.
     */
    public function getParam($param=null)
    {
        if ($param === null) {
            return $this->_params;
        } else if (array_key_exists($param, $this->_params)) {
            return $this->_params[$param];
        } else {
            return null;
        }
    }

    /**
     * Begin running this application.
     *
     * @access  public
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   15 Jul 2005 00:32:21
     */
    public function start()
    {
        if ($this->running) {
            return false;
        }

        // Error reporting.
        ini_set('error_reporting', $this->getParam('error_reporting'));
        ini_set('display_errors', $this->getParam('display_errors'));
        ini_set('log_errors', true);
        if (is_dir($this->getParam('log_directory')) && is_writable($this->getParam('log_directory'))) {
            ini_set('error_log', $this->getParam('log_directory') . '/' . $this->getParam('php_error_log'));
        }

        // Set character set to use for multi-byte string functions.
        mb_internal_encoding($this->getParam('character_set'));
        switch (mb_strtolower($this->getParam('character_set'))) {
        case 'utf-8' :
            mb_language('uni');
            break;

        case 'iso-2022-jp' :
            mb_language('ja');
            break;

        case 'iso-8859-1' :
        default :
            mb_language('en');
            break;
        }

        /**
         * 1. Start Database.
         */

        if (true === $this->getParam('enable_db')) {

            // DB connection parameters taken from environment variables in the server httpd.conf file (readable only by root)

            if (!empty($_SERVER['DB_SERVER']) && !$this->getParam('db_server')) {
                $this->setParam(array('db_server' => $_SERVER['DB_SERVER']));
            }
            if (!empty($_SERVER['DB_NAME']) && !$this->getParam('db_name')) {
                $this->setParam(array('db_name' => $_SERVER['DB_NAME']));
            }
            if (!empty($_SERVER['DB_USER']) && !$this->getParam('db_user')) {
                $this->setParam(array('db_user' => $_SERVER['DB_USER']));
            }
            if (!empty($_SERVER['DB_PASS']) && !$this->getParam('db_pass')) {
                $this->setParam(array('db_pass' => $_SERVER['DB_PASS']));
            }

            // DB credentials for CLI scripts stored in a JSON file with read rights given only to the user who will be executing the scripts: -rw-------
            if (defined('_CLI')) {
                if (false !== $db_auth_file = stream_resolve_include_path($this->getParam('db_auth_file'))) {
                    if (is_readable($db_auth_file)) {
                        $this->setParam(json_decode(file_get_contents($db_auth_file), true));
                    } else {
                        $this->logMsg(sprintf('Unable to read DB auth file: %s', $db_auth_file), LOG_ALERT, __FILE__, __LINE__);
                    }
                } else {
                    $this->logMsg(sprintf('DB auth file not found: %s', $db_auth_file), LOG_ALERT, __FILE__, __LINE__);
                }
            }

            // There will ever only be one instance of the DB object, and here is where it is instantiated.
            require_once dirname(__FILE__) . '/DB.inc.php';
            $this->db =& DB::getInstance();
            $this->db->setParam(array(
                'db_server' => $this->getParam('db_server'),
                'db_name' => $this->getParam('db_name'),
                'db_user' => $this->getParam('db_user'),
                'db_pass' => $this->getParam('db_pass'),
                'db_always_debug' => $this->getParam('db_always_debug'),
                'db_debug' => $this->getParam('db_debug'),
                'db_die_on_failure' => $this->getParam('db_die_on_failure'),
            ));

            // Connect to database.
            $this->db->connect();
        }


        /**
         * 2. Start PHP session.
         */

        // Skip sessions if disabled or automatically skip if run in a CLI script.
        if (true === $this->getParam('enable_session') && !defined('_CLI')) {

            // Session parameters.
            ini_set('session.gc_probability', 1);
            ini_set('session.gc_divisor', 1000);
            ini_set('session.gc_maxlifetime', 43200); // 12 hours
            ini_set('session.use_cookies', $this->getParam('session_use_cookies'));
            ini_set('session.use_trans_sid', false);
            ini_set('session.entropy_file', '/dev/urandom');
            ini_set('session.entropy_length', '512');
            ini_set('session.cookie_httponly', true);
            session_name($this->getParam('session_name'));

            if (true === $this->getParam('enable_db_session_handler') && true === $this->getParam('enable_db')) {
                // Database session handling.
                require_once dirname(__FILE__) . '/DBSessionHandler.inc.php';
                $db_save_handler = new DBSessionHandler($this->db, array(
                    'db_table' => 'session_tbl',
                    'create_table' => $this->getParam('db_create_tables'),
                ));
            }

            // Start the session.
            session_start();

            if (!isset($_SESSION['_app'][$this->_ns])) {
                // Access session data using: $_SESSION['...'].
                // Initialize here _after_ session has started.
                $_SESSION['_app'][$this->_ns] = array(
                    'messages' => array(),
                    'boomerang' => array('url'),
                );
            }
        }


        /**
         * 3. Misc setup.
         */

        // Script URI will be something like http://host.name.tld (no ending slash)
        // and is used whenever a URL need be used to the current site.
        // Not available on cli scripts obviously.
        if (isset($_SERVER['HTTP_HOST']) && '' != $_SERVER['HTTP_HOST'] && '' == $this->getParam('site_url')) {
            $this->setParam(array('site_url' => sprintf('%s://%s', ('on' == getenv('HTTPS') ? 'https' : 'http'), getenv('HTTP_HOST'))));
        }

        // In case site_email isn't set, use something halfway presentable.
        if (isset($_SERVER['HTTP_HOST']) && '' != $_SERVER['HTTP_HOST'] && '' == $this->getParam('site_email')) {
            $this->setParam(array('site_email' => sprintf('no-reply@%s', getenv('HTTP_HOST'))));
        }

        // A key for calculating simple cryptographic signatures.
        if (isset($_SERVER['SIGNING_KEY'])) {
            $this->setParam(array('signing_key' => $_SERVER['SIGNING_KEY']));
        }

        // Character set. This should also be printed in the html header template.
        if (!defined('_CLI')) {
            if (!headers_sent($h_file, $h_line)) {
                header('Content-type: text/html; charset=' . $this->getParam('character_set'));
            } else {
                $this->logMsg(sprintf('Unable to set Content-type; headers already sent (output started in %s : %s)', $h_file, $h_line), LOG_DEBUG, __FILE__, __LINE__);
            }
        }

        // Set the version of the codebase we're using.
        $codebase_version_file = dirname(__FILE__) . '/../docs/version.txt';
        $codebase_version = '';
        if (is_readable($codebase_version_file) && !is_dir($codebase_version_file)) {
            $codebase_version = trim(file_get_contents($codebase_version_file));
            $this->setParam(array('codebase_version' => $codebase_version));
            if (!defined('_CLI')) {
                if (!headers_sent($h_file, $h_line)) {
                    header('X-Codebase-Version: ' . $codebase_version);
                } else {
                    $this->logMsg(sprintf('Unable to set X-Codebase-Version; headers already sent (output started in %s : %s)', $h_file, $h_line), LOG_DEBUG, __FILE__, __LINE__);
                }
            }
        }

        if (version_compare(PHP_VERSION, self::CODEBASE_MIN_PHP_VERSION, '<')) {
            $this->logMsg(sprintf('PHP %s required for Codebase %s, using %s; some things will break.', self::CODEBASE_MIN_PHP_VERSION, $codebase_version, PHP_VERSION), LOG_NOTICE, __FILE__, __LINE__);
        }

        // Set the application version if defined.
        if (false !== $site_version_file = stream_resolve_include_path($this->getParam('site_version_file'))) {
            $site_version = trim(file_get_contents($site_version_file));
            $this->setParam(array('site_version' => $site_version));
            if (!defined('_CLI')) {
                if (!headers_sent($h_file, $h_line)) {
                    header('X-Site-Version: ' . $site_version);
                } else {
                    $this->logMsg(sprintf('Unable to set X-Site-Version; headers already sent (output started in %s : %s)', $h_file, $h_line), LOG_DEBUG, __FILE__, __LINE__);
                }
            }
        }

        $this->running = true;
        return true;
    }

    /**
     * Stop running this application.
     *
     * @access  public
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   17 Jul 2005 17:20:18
     */
    public function stop()
    {
        session_write_close();
        $this->running = false;
        $num_queries = 0;
        if (true === $this->getParam('enable_db')) {
            $num_queries = $this->db->numQueries();
            $this->db->close();
        }
        $mem_current = memory_get_usage();
        $mem_peak = memory_get_peak_usage();
        $this->timer->stop('_app');
        $this->logMsg(sprintf('Script ended gracefully. Execution time: %s. Number of db queries: %s. Memory usage: %s. Peak memory: %s.', $this->timer->getTime('_app'), $num_queries, $mem_current, $mem_peak), LOG_DEBUG, __FILE__, __LINE__);
    }


    /**
     * Add a message to the session, which is printed in the header.
     * Just a simple way to print messages to the user.
     *
     * @access public
     *
     * @param string $message The text description of the message.
     * @param int    $type    The type of message: MSG_NOTICE,
     *                        MSG_SUCCESS, MSG_WARNING, or MSG_ERR.
     * @param string $file    __FILE__.
     * @param string $line    __LINE__.
     */
    public function raiseMsg($message, $type=MSG_NOTICE, $file=null, $line=null)
    {
        $message = trim($message);

        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if (!$this->getParam('enable_session')) {
            $this->logMsg(sprintf('Canceled method call %s, session not enabled.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if ('' == trim($message)) {
            $this->logMsg(sprintf('Raised message is an empty string.', null), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        // Avoid duplicate full-stops..
        $message = trim(preg_replace('/\.{2}$/', '.', $message));

        // Save message in session under unique key to avoid duplicate messages.
        $msg_id = md5($type . $message);
        if (!isset($_SESSION['_app'][$this->_ns]['messages'][$msg_id])) {
            $_SESSION['_app'][$this->_ns]['messages'][$msg_id] = array(
                'type'    => $type,
                'message' => $message,
                'file'    => $file,
                'line'    => $line,
                'count'   => (isset($_SESSION['_app'][$this->_ns]['messages'][$msg_id]['count']) ? (1 + $_SESSION['_app'][$this->_ns]['messages'][$msg_id]['count']) : 1)
            );
        }

        if (!in_array($type, array(MSG_NOTICE, MSG_SUCCESS, MSG_WARNING, MSG_ERR))) {
            $this->logMsg(sprintf('Invalid MSG_* type: %s', $type), LOG_NOTICE, __FILE__, __LINE__);
        }

        // Increment the counter for this message type.
        $this->_raised_msg_counter[$type] += 1;
    }

    /*
    * Returns the number of raised message (all, or by type) for the current script execution (this number may not match the total number of messages stored in session for multiple script executions)
    *
    * @access   public
    * @param
    * @return
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    30 Apr 2015 17:13:03
    */
    public function getRaisedMessageCount($type='all')
    {
        if ('all' == $type) {
            return array_sum($this->_raised_msg_counter);
        } else if (isset($this->_raised_msg_counter[$type])) {
            return $this->_raised_msg_counter[$type];
        } else {
            $this->logMsg(sprintf('Cannot return count of unknown raised message type: %s', $type), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }
    }

    /**
     * Returns an array of the raised messages.
     *
     * @access  public
     * @return  array   List of messages in FIFO order.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   21 Dec 2005 13:09:20
     */
    public function getRaisedMessages()
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }
        return isset($_SESSION['_app'][$this->_ns]['messages']) ? $_SESSION['_app'][$this->_ns]['messages'] : array();
    }

    /**
     * Resets the message list.
     *
     * @access  public
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   21 Dec 2005 13:21:54
     */
    public function clearRaisedMessages()
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        $_SESSION['_app'][$this->_ns]['messages'] = array();
    }

    /**
     * Prints the HTML for displaying raised messages.
     *
     * @param   string  $above    Additional message to print above error messages (e.g. "Oops!").
     * @param   string  $below    Additional message to print below error messages (e.g. "Please fix and resubmit").
     * @param   string  $print_gotohash_js  Print a line of javascript that scrolls the browser window down to view any error messages.
     * @param   string  $hash     The #hashtag to scroll to.
     * @access  public
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   15 Jul 2005 01:39:14
     */
    public function printRaisedMessages($above='', $below='', $print_gotohash_js=false, $hash='sc-msg')
    {

        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        $messages = $this->getRaisedMessages();
        if (!empty($messages)) {
            ?><div id="sc-msg" class="sc-msg"><?php
            if ('' != $above) {
                ?><div class="sc-above"><?php echo oTxt($above); ?></div><?php
            }
            foreach ($messages as $m) {
                if (error_reporting() > 0 && $this->getParam('display_errors') && isset($m['file']) && isset($m['line'])) {
                    echo "\n<!-- [" . $m['file'] . ' : ' . $m['line'] . '] -->';
                }
                switch ($m['type']) {
                case MSG_ERR:
                    echo '<div data-alert class="sc-msg-error alert-box alert">' . $m['message'] . '<a href="#" class="close">&times;</a></div>';
                    break;

                case MSG_WARNING:
                    echo '<div data-alert class="sc-msg-warning alert-box warning">' . $m['message'] . '<a href="#" class="close">&times;</a></div>';
                    break;

                case MSG_SUCCESS:
                    echo '<div data-alert class="sc-msg-success alert-box success">' . $m['message'] . '<a href="#" class="close">&times;</a></div>';
                    break;

                case MSG_NOTICE:
                default:
                    echo '<div data-alert class="sc-msg-notice alert-box info">' . $m['message'] . '<a href="#" class="close">&times;</a></div>';
                    break;
                }
            }
            if ('' != $below) {
                ?><div class="sc-below"><?php echo oTxt($below); ?></div><?php
            }
            ?></div><?php
            if ($print_gotohash_js) {
                ?>
                <script type="text/javascript">
                /* <![CDATA[ */
                window.location.hash = '#<?php echo urlencode($hash); ?>';
                /* ]]> */
                </script>
                <?php
            }
        }
        $this->clearRaisedMessages();
    }

    /**
     * Logs messages to defined channels: file, email, sms, and screen. Repeated messages are
     * not repeated but printed once with count. Log events that match a sendable channel (email or SMS)
     * are sent once per 'log_multiple_timeout' setting (to avoid a flood of error emails).
     *
     * @access public
     * @param string $message   The text description of the message.
     * @param int    $priority  The type of message priority (in descending order):
     *                          LOG_EMERG     0 system is unusable
     *                          LOG_ALERT     1 action must be taken immediately
     *                          LOG_CRIT      2 critical conditions
     *                          LOG_ERR       3 error conditions
     *                          LOG_WARNING   4 warning conditions
     *                          LOG_NOTICE    5 normal, but significant, condition
     *                          LOG_INFO      6 informational message
     *                          LOG_DEBUG     7 debug-level message
     * @param string $file      The file where the log event occurs.
     * @param string $line      The line of the file where the log event occurs.
     */
    public function logMsg($message, $priority=LOG_INFO, $file=null, $line=null)
    {
        static $previous_events = array();

        // If priority is not specified, assume the worst.
        if (!$this->logPriorityToString($priority)) {
            $this->logMsg(sprintf('Log priority %s not defined. (Message: %s)', $priority, $message), LOG_EMERG, $file, $line);
            $priority = LOG_EMERG;
        }

        // If log file is not specified, don't log to a file.
        if (!$this->getParam('log_directory') || !$this->getParam('log_filename') || !is_dir($this->getParam('log_directory')) || !is_writable($this->getParam('log_directory'))) {
            $this->setParam(array('log_file_priority' => false));
            // We must use trigger_error to report this problem rather than calling $app->logMsg, which might lead to an infinite loop.
            trigger_error(sprintf('Codebase error: log directory (%s) not found or writable.', $this->getParam('log_directory')), E_USER_NOTICE);
        }

        // Before we get any further, let's see if ANY log events are configured to be reported.
        if ((false === $this->getParam('log_file_priority') || $priority > $this->getParam('log_file_priority'))
        && (false === $this->getParam('log_email_priority') || $priority > $this->getParam('log_email_priority'))
        && (false === $this->getParam('log_sms_priority') || $priority > $this->getParam('log_sms_priority'))
        && (false === $this->getParam('log_screen_priority') || $priority > $this->getParam('log_screen_priority'))) {
            // This event would not be recorded, skip it entirely.
            return false;
        }

        // Strip HTML tags except any with more than 7 characters because that's probably not a HTML tag, e.g. <email@address.com>.
        preg_match_all('/(<[^>\s]{7,})[^>]*>/', $message, $strip_tags_allow);
        $message = strip_tags(preg_replace('/\s+/', ' ', $message), (!empty($strip_tags_allow[1]) ? join('> ', $strip_tags_allow[1]) . '>' : null));

        // Serialize multi-line messages.
        $message = preg_replace('/\s+/m', ' ', $message);

        // Store this event under a unique key, counting each time it occurs so that it only gets reported a limited number of times.
        $msg_id = md5($message . $priority . $file . $line);
        if ($this->getParam('log_ignore_repeated_events') && isset($previous_events[$msg_id])) {
            $previous_events[$msg_id]++;
            if ($previous_events[$msg_id] == 2) {
                $this->logMsg(sprintf('%s (Event repeated %s or more times)', $message, $previous_events[$msg_id]), $priority, $file, $line);
            }
            return false;
        } else {
            $previous_events[$msg_id] = 1;
        }

        // For email and SMS notification types use "lock" files to prevent sending email and SMS notices ad infinitum.
        if ((false !== $this->getParam('log_email_priority') && $priority <= $this->getParam('log_email_priority'))
        || (false !== $this->getParam('log_sms_priority') && $priority <= $this->getParam('log_sms_priority'))) {
            // This event will generate a "send" notification. Prepare lock file.
            $site_hash = md5(empty($_SERVER['SERVER_NAME']) ? $_SERVER['SCRIPT_FILENAME'] : $_SERVER['SERVER_NAME']);
            $lock_dir = $this->getParam('tmp_dir') . "/codebase_msgs_$site_hash/";
            // Just use the file and line for the msg_id to limit the number of possible messages
            // (the message string itself shan't be used as it may contain innumerable combinations).
            $lock_file = $lock_dir . md5($file . ':' . $line);
            if (!is_dir($lock_dir)) {
                mkdir($lock_dir);
            }
            $send_notifications = true;
            if (is_file($lock_file)) {
                $msg_last_sent = filectime($lock_file);
                // Has this message been sent more recently than the timeout?
                if ((time() - $msg_last_sent) <= $this->getParam('log_multiple_timeout')) {
                    // This message was already sent recently.
                    $send_notifications = false;
                } else {
                    // Timeout has expired; send notifications again and reset timeout.
                    touch($lock_file);
                }
            } else {
                touch($lock_file);
            }
        }

        // Make sure to log in the system's locale.
        $locale = setlocale(LC_TIME, 0);
        setlocale(LC_TIME, 'C');

        // Data to be stored for a log event.
        $event = array(
            'date'      => date('Y-m-d H:i:s'),
            'remote ip' => getRemoteAddr(),
            'pid'       => getmypid(),
            'type'      => $this->logPriorityToString($priority),
            'file:line' => "$file : $line",
            'url'       => mb_substr(isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '', 0, 1024),
            'message'   => $message
        );
        // Here's a shortened version of event data.
        $event_short = $event;
        $event_short['url'] = truncate($event_short['url'], 120);

        // Restore original locale.
        setlocale(LC_TIME, $locale);

        // FILE ACTION
        if (false !== $this->getParam('log_file_priority') && $priority <= $this->getParam('log_file_priority')) {
            $event_str = '[' . join('] [', $event_short) . ']';
            error_log(mb_substr($event_str, 0, 1024) . "\n", 3, $this->getParam('log_directory') . '/' . $this->getParam('log_filename'));
        }

        // EMAIL ACTION
        if (false !== $this->getParam('log_email_priority') && $priority <= $this->getParam('log_email_priority') && $send_notifications) {
            $hostname = (isset($_SERVER['HTTP_HOST']) && '' != $_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : php_uname('n');
            $subject = sprintf('[%s %s] %s', $hostname, $event['type'], mb_substr($event['message'], 0, 64));
            $email_msg = sprintf("A %s log event occurred on %s\n\n", $event['type'], $hostname);
            $headers = 'From: ' . $this->getParam('site_email');
            foreach ($event as $k=>$v) {
                $email_msg .= sprintf("%-11s%s\n", $k, $v);
            }
            mb_send_mail($this->getParam('log_to_email_address'), $subject, $email_msg, $headers);
        }

        // SMS ACTION
        if (false !== $this->getParam('log_sms_priority') && $priority <= $this->getParam('log_sms_priority') && $send_notifications) {
            $hostname = (isset($_SERVER['HTTP_HOST']) && '' != $_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : php_uname('n');
            $subject = sprintf('[%s %s]', $hostname, $priority);
            $sms_msg = sprintf('%s [%s:%s]', mb_substr($event_short['message'], 0, 64), basename($file), $line);
            $headers = 'From: ' . $this->getParam('site_email');
            mb_send_mail($this->getParam('log_to_sms_address'), $subject, $sms_msg, $headers);
        }

        // SCREEN ACTION
        if (false !== $this->getParam('log_screen_priority') && $priority <= $this->getParam('log_screen_priority')) {
            file_put_contents('php://stderr', "[{$event['type']}] [{$event['message']}]\n", FILE_APPEND);
        }

        return true;
    }

    /**
     * Returns the string representation of a LOG_* integer constant.
     *
     * @param int  $priority  The LOG_* integer constant.
     *
     * @return                The string representation of $priority.
     */
    public function logPriorityToString($priority) {
        $priorities = array(
            LOG_EMERG   => 'emergency',
            LOG_ALERT   => 'alert',
            LOG_CRIT    => 'critical',
            LOG_ERR     => 'error',
            LOG_WARNING => 'warning',
            LOG_NOTICE  => 'notice',
            LOG_INFO    => 'info',
            LOG_DEBUG   => 'debug'
        );
        if (isset($priorities[$priority])) {
            return $priorities[$priority];
        } else {
            return false;
        }
    }

    /**
     * Forcefully set a query argument even if one currently exists in the request.
     * Values in the _carry_queries array will be copied to URLs (via $app->url()) and
     * to hidden input values (via printHiddenSession()).
     *
     * @access  public
     * @param   mixed   $query_key  The key (or keys, as an array) of the query argument to save.
     * @param   mixed   $val        The new value of the argument key.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   13 Oct 2007 11:34:51
     */
    public function setQuery($query_key, $val)
    {
        if (!is_array($query_key)) {
            $query_key = array($query_key);
        }
        foreach ($query_key as $k) {
            // Set the value of the specified query argument into the _carry_queries array.
            $this->_carry_queries[$k] = $val;
        }
    }

    /**
     * Specify which query arguments will be carried persistently between requests.
     * Values in the _carry_queries array will be copied to URLs (via $app->url()) and
     * to hidden input values (via printHiddenSession()).
     *
     * @access  public
     * @param   mixed   $query_key   The key (or keys, as an array) of the query argument to save.
     * @param   mixed   $default    If the key is not available, set to this default value.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   14 Nov 2005 19:24:52
     */
    public function carryQuery($query_key, $default=false)
    {
        if (!is_array($query_key)) {
            $query_key = array($query_key);
        }
        foreach ($query_key as $k) {
            // If not already set, and there is a non-empty value provided in the request...
            if (!isset($this->_carry_queries[$k]) && false !== getFormData($k, $default)) {
                // Copy the value of the specified query argument into the _carry_queries array.
                $this->_carry_queries[$k] = getFormData($k, $default);
                $this->logMsg(sprintf('Carrying query: %s => %s', $k, truncate(getDump($this->_carry_queries[$k], true), 128, 'end')), LOG_DEBUG, __FILE__, __LINE__);
            }
        }
    }

    /**
     * dropQuery() is the opposite of carryQuery(). The specified value will not appear in
     * url()/ohref()/printHiddenSession() modified URLs unless explicitly written in.
     *
     * @access  public
     * @param   mixed   $query_key  The key (or keys, as an array) of the query argument to remove.
     * @param   bool    $unset      Remove any values set in the request matching the given $query_key.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   18 Jun 2007 20:57:29
     */
    public function dropQuery($query_key, $unset=false)
    {
        if (!is_array($query_key)) {
            $query_key = array($query_key);
        }
        foreach ($query_key as $k) {
            if (array_key_exists($k, $this->_carry_queries)) {
                // Remove the value of the specified query argument from the _carry_queries array.
                $this->logMsg(sprintf('Dropping carried query: %s => %s', $k, $this->_carry_queries[$k]), LOG_DEBUG, __FILE__, __LINE__);
                unset($this->_carry_queries[$k]);
            }
            if ($unset && (isset($_REQUEST) && array_key_exists($k, $_REQUEST))) {
                unset($_REQUEST[$k], $_GET[$k], $_POST[$k], $_COOKIE[$k]);
            }
        }
    }

    /**
     * Outputs a fully qualified URL with a query of all the used (ie: not empty)
     * keys and values, including optional queries. This allows mindless retention
     * of query arguments across page requests. If cookies are not
     * used and session_use_trans_sid=true the session id will be propagated in the URL.
     *
     * @param  string $url              The initial url
     * @param  mixed  $carry_args       Additional url arguments to carry in the query,
     *                                  or FALSE to prevent carrying queries. Can be any of the following formats:
     *                                      array('key1', key2', key3')  <-- to save these keys if in the form data.
     *                                      array('key1'=>'value', key2'='value')  <-- to set keys to default values if not present in form data.
     *                                      false  <-- To not carry any queries. If URL already has queries those will be retained.
     *
     * @param  mixed  $always_include_sid  Always add the session id, even if using_trans_sid = true. This is required when
     *                                     URL starts with http, since PHP using_trans_sid doesn't do those and also for
     *                                     header('Location...') redirections.
     *
     * @param   bool    $include_csrf_token     Set to true to include the csrf_token in the form. Only use this for forms with action="post" to prevent the token from being revealed in the URL.
     * @return string url with attached queries and, if not using cookies, the session id
     */
    public function url($url, $carry_args=null, $always_include_sid=false, $include_csrf_token=false)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if ($this->getParam('csrf_token_enabled') && $include_csrf_token) {
            // Include the csrf_token as a carried query argument.
            // This token can be validated upon form submission with $app->verifyCSRFToken() or $app->requireValidCSRFToken()
            $carry_args = is_array($carry_args) ? $carry_args : array();
            $carry_args = array_merge($carry_args, array($this->getParam('csrf_token_name') => $this->getCSRFToken()));
        }

        // Get any provided query arguments to include in the final URL.
        // If FALSE is a provided here, DO NOT carry the queries.
        $do_carry_queries = true;
        $one_time_carry_queries = array();
        if (!is_null($carry_args)) {
            if (is_array($carry_args) && !empty($carry_args)) {
                foreach ($carry_args as $key=>$arg) {
                    // Get query from appropriate source.
                    if (false === $arg) {
                        $do_carry_queries = false;
                    } else if (false !== getFormData($arg, false)) {
                        $one_time_carry_queries[$arg] = getFormData($arg); // Set arg to form data if available.
                    } else if (!is_numeric($key) && '' != $arg) {
                        $one_time_carry_queries[$key] = getFormData($key, $arg); // Set to arg to default if specified (overwritten by form data).
                    }
                }
            } else if (false !== getFormData($carry_args, false)) {
                $one_time_carry_queries[$carry_args] = getFormData($carry_args);
            } else if (false === $carry_args) {
                $do_carry_queries = false;
            }
        }

        // Get the first delimiter that is needed in the url.
        $delim = mb_strpos($url, '?') !== false ? ini_get('arg_separator.output') : '?';

        $q = '';
        if ($do_carry_queries) {
            // Join the global _carry_queries and local one_time_carry_queries.
            $query_args = urlEncodeArray(array_merge($this->_carry_queries, $one_time_carry_queries));
            foreach ($query_args as $key=>$val) {
                // Check value is set and value does not already exist in the url.
                if (!preg_match('/[?&]' . preg_quote($key) . '=/', $url)) {
                    $q .= $delim . $key . '=' . $val;
                    $delim = ini_get('arg_separator.output');
                }
            }
        }

        // Include the necessary SID if the following is true:
        // - no cookie in http request OR cookies disabled in App
        // - sessions are enabled
        // - the link stays on our site
        // - transparent SID propagation with session.use_trans_sid is not being used OR url begins with protocol (using_trans_sid has no effect here)
        // OR
        // - we must include the SID because we say so (it's used in a context where cookies will not be effective, ie. moving from http to https)
        // AND
        // - the SID is not already in the query.
        if (
            (
                (
                    (
                        !isset($_COOKIE[session_name()])
                        || !$this->getParam('session_use_cookies')
                    )
                    && $this->getParam('session_use_trans_sid')
                    && $this->getParam('enable_session')
                    && isMyDomain($url)
                    && (
                        !ini_get('session.use_trans_sid')
                        || preg_match('!^(http|https)://!i', $url)
                    )
                )
                || $always_include_sid
            )
            && !preg_match('/[?&]' . preg_quote(session_name()) . '=/', $url)
        ) {
            $url .= $q . $delim . session_name() . '=' . session_id();
        } else {
            $url .= $q;
        }

        return $url;
    }

    /**
     * Returns a HTML-friendly URL processed with $app->url and & replaced with &amp;
     *
     * @access  public
     * @param   (see param reference for url() method)
     * @return  string          URL passed through $app->url() with ampersands transformed to $amp;
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   09 Dec 2005 17:58:45
     */
    public function oHREF($url, $carry_args=null, $always_include_sid=false, $include_csrf_token=false)
    {
        // Process the URL.
        $url = $this->url($url, $carry_args, $always_include_sid, $include_csrf_token);

        // Replace any & not followed by an html or unicode entity with its &amp; equivalent.
        $url = preg_replace('/&(?![\w\d#]{1,10};)/', '&amp;', $url);

        return $url;
    }

    /**
     * Prints a hidden form element with the PHPSESSID when cookies are not used, as well
     * as hidden form elements for GET_VARS that might be in use.
     *
     * @param  mixed  $carry_args        Additional url arguments to carry in the query,
     *                                   or FALSE to prevent carrying queries. Can be any of the following formats:
     *                                      array('key1', key2', key3')  <-- to save these keys if in the form data.
     *                                      array('key1'=>'value', key2'='value')  <-- to set keys to default values if not present in form data.
     *                                      false  <-- To not carry any queries. If URL already has queries those will be retained.
     * @param   bool    $include_csrf_token     Set to true to include the csrf_token in the form. Only use this for forms with action="post" to prevent the token from being revealed in the URL.
     */
    public function printHiddenSession($carry_args=null, $include_csrf_token=false)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        // Get any provided query arguments to include in the final hidden form data.
        // If FALSE is a provided here, DO NOT carry the queries.
        $do_carry_queries = true;
        $one_time_carry_queries = array();
        if (!is_null($carry_args)) {
            if (is_array($carry_args) && !empty($carry_args)) {
                foreach ($carry_args as $key=>$arg) {
                    // Get query from appropriate source.
                    if (false === $arg) {
                        $do_carry_queries = false;
                    } else if (false !== getFormData($arg, false)) {
                        $one_time_carry_queries[$arg] = getFormData($arg); // Set arg to form data if available.
                    } else if (!is_numeric($key) && '' != $arg) {
                        $one_time_carry_queries[$key] = getFormData($key, $arg); // Set to arg to default if specified (overwritten by form data).
                    }
                }
            } else if (false !== getFormData($carry_args, false)) {
                $one_time_carry_queries[$carry_args] = getFormData($carry_args);
            } else if (false === $carry_args) {
                $do_carry_queries = false;
            }
        }

        // For each existing request value, we create a hidden input to carry it through a form.
        if ($do_carry_queries) {
            // Join the global _carry_queries and local one_time_carry_queries.
            // urlencode is not used here, not for form data!
            $query_args = array_merge($this->_carry_queries, $one_time_carry_queries);
            foreach ($query_args as $key => $val) {
                if (is_array($val)) {
                    foreach ($val as $subval) {
                        printf('<input type="hidden" name="%s[]" value="%s" />', $key, $subval);
                    }
                } else {
                    printf('<input type="hidden" name="%s" value="%s" />', $key, $val);
                }
            }
            unset($query_args, $key, $val, $subval);
        }

        // Include the SID if:
        // * cookies are disabled
        // * the system isn't automatically adding trans_sid
        // * the session is enabled
        // * and we're configured to use trans_sid
        if (!isset($_COOKIE[session_name()])
        && !ini_get('session.use_trans_sid')
        && $this->getParam('enable_session')
        && $this->getParam('session_use_trans_sid')
        ) {
            printf('<input type="hidden" name="%s" value="%s" />', session_name(), session_id());
        }

        // Include the csrf_token in the form.
        // This token can be validated upon form submission with $app->verifyCSRFToken() or $app->requireValidCSRFToken()
        if ($this->getParam('csrf_token_enabled') && $include_csrf_token) {
            printf('<input type="hidden" name="%s" value="%s" />', $this->getParam('csrf_token_name'), $this->getCSRFToken());
        }
    }

    /*
    * Return a URL with a version number attached. This is useful for overriding network caches ("cache buster") for sourced media, e.g., /style.css?812763482
    *
    * @access   public
    * @param    string  $url    URL to media (e.g., /foo.js)
    * @return   string          URL with cache-busting version appended (/foo.js?v=1234567890)
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    03 Sep 2014 22:40:24
    */
    public function cacheBustURL($url)
    {
        // Get the first delimiter that is needed in the url.
        $delim = mb_strpos($url, '?') !== false ? ini_get('arg_separator.output') : '?';
        $v = crc32($this->getParam('codebase_version') . '|' . $this->getParam('site_version'));
        return sprintf('%s%sv=%s', $url, $delim, $v);
    }

    /*
    * Generate a csrf_token if it doesn't exist or is expired, save it to the session and return its value.
    * Otherwise just return the current token.
    * Details on the synchronizer token pattern:
    * https://www.owasp.org/index.php/Cross-Site_Request_Forgery_(CSRF)_Prevention_Cheat_Sheet#General_Recommendation:_Synchronizer_Token_Pattern
    *
    * @access   public
    * @return   string The new or current csrf_token
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    15 Nov 2014 17:57:17
    */
    public function getCSRFToken()
    {
        if (!isset($_SESSION['_app'][$this->_ns]['csrf_token']) || (removeSignature($_SESSION['_app'][$this->_ns]['csrf_token']) + $this->getParam('csrf_token_timeout') < time())) {
            // No token, or token is expired; generate one and return it.
            return $_SESSION['_app'][$this->_ns]['csrf_token'] = addSignature(time(), null, 64);
        }
        // Current token is not expired; return it.
        return $_SESSION['_app'][$this->_ns]['csrf_token'];
    }

    /*
    * Compares the given csrf_token with the current or previous one saved in the session.
    *
    * @access   public
    * @param    string  $csrf_token     The token to compare with the session token.
    * @return   bool    True if the tokens match, false otherwise.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    15 Nov 2014 18:06:55
    */
    public function verifyCSRFToken($user_submitted_csrf_token)
    {

        if (!$this->getParam('csrf_token_enabled')) {
            $this->logMsg(sprintf('%s method called, but csrf_token_enabled=false', __FUNCTION__), LOG_ERR, __FILE__, __LINE__);
            return true;
        }
        if ('' == trim($user_submitted_csrf_token)) {
            $this->logMsg(sprintf('Empty string failed CSRF verification.', null), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }
        if (!verifySignature($user_submitted_csrf_token, null, 64)) {
            $this->logMsg(sprintf('Input failed CSRF verification (invalid signature in %s).', $user_submitted_csrf_token), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }
        $csrf_token = $this->getCSRFToken();
        if ($user_submitted_csrf_token != $csrf_token) {
            $this->logMsg(sprintf('Input failed CSRF verification (%s not in %s).', $user_submitted_csrf_token, $csrf_token), LOG_WARNING, __FILE__, __LINE__);
            return false;
        }
        $this->logMsg(sprintf('Verified CSRF token %s', $user_submitted_csrf_token), LOG_DEBUG, __FILE__, __LINE__);
        return true;
    }

    /*
    * Bounce user if they submit a token that doesn't match the one saved in the session.
    * Because this function calls dieURL() it must be called before any other HTTP header output.
    *
    * @access   public
    * @param    string  $user_submitted_csrf_token The user-submitted token to compare with the session token.
    * @param    string  $message    Optional message to display to the user (otherwise default message will display). Set to an empty string to display no message.
    * @param    int    $type    The type of message: MSG_NOTICE,
    *                           MSG_SUCCESS, MSG_WARNING, or MSG_ERR.
    * @param    string $file    __FILE__.
    * @param    string $line    __LINE__.
    * @return   void
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    15 Nov 2014 18:10:17
    */
    public function requireValidCSRFToken($message=null, $type=MSG_NOTICE, $file=null, $line=null)
    {
        if (!$this->verifyCSRFToken(getFormData($this->getParam('csrf_token_name')))) {
            $message = isset($message) ? $message : _("Sorry, the form token expired. Please try again.");
            $this->raiseMsg($message, $type, $file, $line);
            $this->dieBoomerangURL();
        }
    }

    /**
     * Uses an http header to redirect the client to the given $url. If sessions are not used
     * and the session is not already defined in the given $url, the SID is appended as a URI query.
     * As with all header generating functions, make sure this is called before any other output.
     *
     * @param   string  $url                    The URL the client will be redirected to.
     * @param   mixed   $carry_args             Additional url arguments to carry in the query,
     *                                          or FALSE to prevent carrying queries. Can be any of the following formats:
     *                                          -array('key1', key2', key3')  <-- to save these keys if in the form data.
     *                                          -array('key1' => 'value', key2' => 'value')  <-- to set keys to default values if not present in form data.
     *                                          -false  <-- To not carry any queries. If URL already has queries those will be retained.
     * @param   bool    $always_include_sid     Force session id to be added to Location header.
     */
    public function dieURL($url, $carry_args=null, $always_include_sid=false)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if (!$url) {
            // If URL is not specified, use the redirect_home_url.
            $url = $this->getParam('redirect_home_url');
        }

        if (preg_match('!^/!', $url)) {
            // If relative URL is given, prepend correct local hostname.
            $scheme = 'on' == getenv('HTTPS') ? 'https' : 'http';
            $host = getenv('HTTP_HOST');
            $url = sprintf('%s://%s%s', $scheme, $host, $url);
        }

        $url = $this->url($url, $carry_args, $always_include_sid);

        // Should we send a "303 See Other" header here instead of relying on the 302 sent automatically by PHP?
        if (!headers_sent($h_file, $h_line)) {
            header(sprintf('Location: %s', $url));
            $this->logMsg(sprintf('dieURL: %s', $url), LOG_DEBUG, __FILE__, __LINE__);
        } else {
            // Fallback: die using meta refresh instead.
            printf('<meta http-equiv="refresh" content="0;url=%s" />', $url);
            $this->logMsg(sprintf('dieURL (refresh): %s; headers already sent (output started in %s : %s)', $url, $h_file, $h_line), LOG_NOTICE, __FILE__, __LINE__);
        }

        // End application.
        // Recommended, although I'm not sure it's necessary: http://cn2.php.net/session_write_close
        $this->stop();
        die;
    }

    /*
    * Redirects a user by calling $app->dieURL(). It will use:
    * 1. the stored boomerang URL, it it exists
    * 2. a specified $default_url, it it exists
    * 3. the referring URL, it it exists.
    * 4. redirect_home_url configuration variable.
    *
    * @access   public
    * @param    string  $id             Identifier for this script.
    * @param    mixed   $carry_args     Additional arguments to carry in the URL automatically (see $app->oHREF()).
    * @param    string  $default_url    A default URL if there is not a valid specified boomerang URL.
    * @param    bool    $queryless_referrer_comparison   Exclude the URL query from the refererIsMe() comparison.
    * @return   bool                    False if the session is not running. No return otherwise.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @since    31 Mar 2006 19:17:00
    */
    public function dieBoomerangURL($id=null, $carry_args=null, $default_url=null, $queryless_referrer_comparison=false)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        // Get URL from stored boomerang. Allow non specific URL if ID not valid.
        if ($this->validBoomerangURL($id, true)) {
            if (isset($id) && isset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$id])) {
                $url = $_SESSION['_app'][$this->_ns]['boomerang']['url'][$id];
                $this->logMsg(sprintf('dieBoomerangURL(%s) found: %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
            } else {
                $url = end($_SESSION['_app'][$this->_ns]['boomerang']['url']);
                $this->logMsg(sprintf('dieBoomerangURL(%s) using: %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
            }
            // Delete stored boomerang.
            $this->deleteBoomerangURL($id);
        } else if (isset($default_url)) {
            $url = $default_url;
        } else if (!refererIsMe(true === $queryless_referrer_comparison) && '' != ($url = getenv('HTTP_REFERER'))) {
            // Ensure that the redirecting page is not also the referrer.
            $this->logMsg(sprintf('dieBoomerangURL(%s) using referrer: %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
        } else {
            // If URL is not specified, use the redirect_home_url.
            $url = $this->getParam('redirect_home_url');
            $this->logMsg(sprintf('dieBoomerangURL(%s) using redirect_home_url: %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
        }

        // A redirection will never happen immediately twice.
        // Set the time so ensure this doesn't happen.
        $_SESSION['_app'][$this->_ns]['boomerang']['time'] = time();
        $this->dieURL($url, $carry_args);
    }

    /**
     * Set the URL to return to when $app->dieBoomerangURL() is called.
     *
     * @param string  $url  A fully validated URL.
     * @param bool  $id     An identification tag for this url.
     * FIXME: url garbage collection?
     */
    public function setBoomerangURL($url=null, $id=null)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }
        // A redirection will never happen immediately after setting the boomerangURL.
        // Set the time so ensure this doesn't happen. See $app->validBoomerangURL for more.

        if ('' != $url && is_string($url)) {
            // Delete any boomerang request keys in the query string (along with any trailing delimiters after the deletion).
            $url = preg_replace(array('/([&?])boomerang=\w+[&?]?/', '/[&?]$/'), array('$1', ''), $url);

            if (isset($_SESSION['_app'][$this->_ns]['boomerang']['url']) && is_array($_SESSION['_app'][$this->_ns]['boomerang']['url']) && !empty($_SESSION['_app'][$this->_ns]['boomerang']['url'])) {
                // If the URL currently exists in the boomerang array, delete.
                while ($existing_key = array_search($url, $_SESSION['_app'][$this->_ns]['boomerang']['url'])) {
                    unset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$existing_key]);
                }
            }

            if (isset($id)) {
                $_SESSION['_app'][$this->_ns]['boomerang']['url'][$id] = $url;
            } else {
                $_SESSION['_app'][$this->_ns]['boomerang']['url'][] = $url;
            }
            $this->logMsg(sprintf('setBoomerangURL(%s): %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
            return true;
        } else {
            $this->logMsg(sprintf('setBoomerangURL(%s) is empty!', $id, $url), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }
    }

    /**
     * Return the URL set for the specified $id, or an empty string if one isn't set.
     *
     * @param string  $id     An identification tag for this url.
     */
    public function getBoomerangURL($id=null)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if (isset($id)) {
            if (isset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$id])) {
                return $_SESSION['_app'][$this->_ns]['boomerang']['url'][$id];
            } else {
                return '';
            }
        } else if (is_array($_SESSION['_app'][$this->_ns]['boomerang']['url'])) {
            return end($_SESSION['_app'][$this->_ns]['boomerang']['url']);
        } else {
            return false;
        }
    }

    /**
     * Delete the URL set for the specified $id.
     *
     * @param string  $id     An identification tag for this url.
     */
    public function deleteBoomerangURL($id=null)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if (isset($id) && isset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$id])) {
            $url = $this->getBoomerangURL($id);
            unset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$id]);
        } else if (is_array($_SESSION['_app'][$this->_ns]['boomerang']['url'])) {
            $url = array_pop($_SESSION['_app'][$this->_ns]['boomerang']['url']);
        }
        $this->logMsg(sprintf('deleteBoomerangURL(%s): %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
    }

    /**
     * Check if a valid boomerang URL value has been set. A boomerang URL is considered
     * valid if: 1) it is not empty, 2) it is not the current URL, and 3) has not been accessed within n seconds.
     *
     * @return bool  True if it is set and valid, false otherwise.
     */
    public function validBoomerangURL($id=null, $use_nonspecificboomerang=false)
    {
        if (!$this->running) {
            $this->logMsg(sprintf('Canceled method call %s, application not running.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        if (!isset($_SESSION['_app'][$this->_ns]['boomerang']['url'])) {
            $this->logMsg(sprintf('validBoomerangURL(%s) no boomerang URL set.', $id), LOG_DEBUG, __FILE__, __LINE__);
            return false;
        }

        // Time is the time stamp of a boomerangURL redirection, or setting of a boomerangURL.
        // a boomerang redirection will always occur at least several seconds after the last boomerang redirect
        // or a boomerang being set.
        $boomerang_time = isset($_SESSION['_app'][$this->_ns]['boomerang']['time']) ? $_SESSION['_app'][$this->_ns]['boomerang']['time'] : 0;

        $url = '';
        if (isset($id) && isset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$id])) {
            $url = $_SESSION['_app'][$this->_ns]['boomerang']['url'][$id];
        } else if (!isset($id) || $use_nonspecificboomerang) {
            // Use non specific boomerang if available.
            $url = end($_SESSION['_app'][$this->_ns]['boomerang']['url']);
        }

        $this->logMsg(sprintf('validBoomerangURL(%s) testing: %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);

        if ('' == $url) {
            $this->logMsg(sprintf('validBoomerangURL(%s) not valid, empty!', $id), LOG_DEBUG, __FILE__, __LINE__);
            return false;
        }
        if ($url == absoluteMe()) {
            // The URL we are directing to is the current page.
            $this->logMsg(sprintf('validBoomerangURL(%s) not valid, same as absoluteMe: %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
            return false;
        }
        if ($boomerang_time >= (time() - 2)) {
            // Last boomerang direction was less than 2 seconds ago.
            $this->logMsg(sprintf('validBoomerangURL(%s) not valid, boomerang_time too short: %s seconds', $id, time() - $boomerang_time), LOG_DEBUG, __FILE__, __LINE__);
            return false;
        }

        $this->logMsg(sprintf('validBoomerangURL(%s) is valid: %s', $id, $url), LOG_DEBUG, __FILE__, __LINE__);
        return true;
    }

    /**
     * Force the user to connect via https (port 443) by redirecting them to
     * the same page but with https.
     */
    public function sslOn()
    {
        if (function_exists('apache_get_modules')) {
            $modules = apache_get_modules();
        } else {
            // It's safe to assume we have mod_ssl if we can't determine otherwise.
            $modules = array('mod_ssl');
        }

        if ('' == getenv('HTTPS') && $this->getParam('ssl_enabled') && in_array('mod_ssl', $modules)) {
            $this->raiseMsg(sprintf(_("Secure SSL connection made to %s"), $this->getParam('ssl_domain')), MSG_NOTICE, __FILE__, __LINE__);
            // Always append session because some browsers do not send cookie when crossing to SSL URL.
            $this->dieURL('https://' . $this->getParam('ssl_domain') . getenv('REQUEST_URI'), null, true);
        }
    }

    /**
     * to enforce the user to connect via http (port 80) by redirecting them to
     * a http version of the current url.
     */
    public function sslOff()
    {
        if ('' != getenv('HTTPS')) {
            $this->dieURL('http://' . getenv('HTTP_HOST') . getenv('REQUEST_URI'), null, true);
        }
    }

    /*
    * Sets a cookie, with error checking and some sane defaults.
    *
    * @access   public
    * @param    string  $name       The name of the cookie.
    * @param    string  $value      The value of the cookie.
    * @param    string  $expire     The time the cookie expires, as a unix timestamp or string value passed to strtotime.
    * @param    string  $path       The path on the server in which the cookie will be available on.
    * @param    string  $domain     The domain that the cookie is available to.
    * @param    bool    $secure     Indicates that the cookie should only be transmitted over a secure HTTPS connection from the client.
    * @param    bool    $httponly   When TRUE the cookie will be made accessible only through the HTTP protocol (makes cookies unreadable to javascript).
    * @return   bool                True on success, false on error.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @version  1.0
    * @since    02 May 2014 16:36:34
    */
    public function setCookie($name, $value, $expire='+10 years', $path='/', $domain=null, $secure=null, $httponly=null)
    {
        if (!is_scalar($name)) {
            $this->logMsg(sprintf('Cookie name must be scalar, is not: %s', getDump($name)), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }
        if (!is_scalar($value)) {
            $this->logMsg(sprintf('Cookie "%s" value must be scalar, is not: %s', $name, getDump($value)), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        // Defaults.
        $expire = (is_numeric($expire) ? $expire : (is_string($expire) ? strtotime($expire) : $expire));
        $secure = $secure ?: ('' != getenv('HTTPS') && $this->getParam('ssl_enabled'));
        $httponly = $httponly ?: true;

        // Make sure the expiration date is a valid 32bit integer.
        if (is_int($expire) && $expire > 2147483647) {
            $this->logMsg(sprintf('Cookie "%s" expire time exceeds a 32bit integer (%s)', $key, date('r', $expire)), LOG_NOTICE, __FILE__, __LINE__);
        }

        // Measure total cookie length and warn if larger than max recommended size of 4093.
        // https://stackoverflow.com/questions/640938/what-is-the-maximum-size-of-a-web-browsers-cookies-key
        // The date the header name include 51 bytes: Set-Cookie: ; expires=Fri, 03-May-2024 00:04:47 GMT
        $cookielen = strlen($name . $value . $path . $domain . ($secure ? '; secure' : '') . ($httponly ? '; httponly' : '')) + 51;
        if ($cookielen > 4093) {
            $this->logMsg(sprintf('Cookie "%s" has a size greater than 4093 bytes (is %s bytes)', $key, $cookielen), LOG_NOTICE, __FILE__, __LINE__);
        }

        // Ensure PHP version allow use of httponly.
        if (version_compare(PHP_VERSION, '5.2.0', '>=')) {
            $ret = setcookie($name, $value, $expire, $path, $domain, $secure, $httponly);
        } else {
            $ret = setcookie($name, $value, $expire, $path, $domain, $secure);
        }

        if (false === $ret) {
            $this->logMsg(sprintf('Failed to set cookie (%s=%s) probably due to output before headers.', $name, $value), LOG_NOTICE, __FILE__, __LINE__);
        }
        return $ret;
    }
} // End.