<?php
/**
 * The Strangecode Codebase - a general application development framework for PHP
 * For details visit the project site: <http://trac.strangecode.com/codebase/>
 * Copyright 2001-2010 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 {

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

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

    // Instance of database object.
    var $db;

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

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

    // Default parameters.
    var $_param_defaults = array(

        // Public name and email address for this application.
        'site_name' => null,
        'site_email' => null,
        'site_url' => '', // URL automatically determined by _SERVER['HTTP_HOST'] if not set here.
        'images_path' => '', // Location for codebase-generated interface widgets (ex: "/admin/i").

        // 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,

        // 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 passwords 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,

        // 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.
        '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' => 300,

        // 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.
        'log_to_email_address' => null,

        // SMS Email address to receive log event SMS messages.
        'log_to_sms_address' => null,

        // 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',
    );

    /**
     * This method enforces the singleton pattern for this class. Only one application is running at a time.
     *
     * $param   string  $namespace  Name of this application.
     * @return  object  Reference to the global Cache object.
     * @access  public
     * @static
     */
    function &getInstance($namespace='')
    {
        static $instance = null;

        if ($instance === null) {
            $instance = new App($namespace);
        }

        return $instance;
    }

    /**
     * Constructor.
     */
    function App($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');
    }

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

    /**
     * Return the value of a parameter.
     *
     * @access  public
     * @param   string  $param      The key of the parameter to return.
     * @return  mixed               Parameter value, or null if not existing.
     */
    function getParam($param=null)
    {
        if ($param === null) {
            return $this->_params;
        } else if (isset($this->_params[$param])) {
            return $this->_params[$param];
        } else {
            trigger_error(sprintf('Parameter is not set: %s', $param), E_USER_NOTICE);
            return null;
        }
    }

    /**
     * Begin running this application.
     *
     * @access  public
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   15 Jul 2005 00:32:21
     */
    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 httpd.conf file, readable only by root.
            if (!empty($_SERVER['DB_SERVER'])) {
                $this->setParam(array('db_server' => $_SERVER['DB_SERVER']));
            }
            if (!empty($_SERVER['DB_NAME'])) {
                $this->setParam(array('db_name' => $_SERVER['DB_NAME']));
            }
            if (!empty($_SERVER['DB_USER'])) {
                $this->setParam(array('db_user' => $_SERVER['DB_USER']));
            }
            if (!empty($_SERVER['DB_PASS'])) {
                $this->setParam(array('db_pass' => $_SERVER['DB_PASS']));
            }

            // 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 session for some user agents.
        if (preg_match('/Atomz|ApacheBench|Wget/i', getenv('HTTP_USER_AGENT'))) {
            $this->setParam(array('enable_session' => false));
        }

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

            // 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', $this->getParam('session_use_cookies'));
            ini_set('session.use_trans_sid', false);
            ini_set('session.entropy_file', '/dev/urandom');
            ini_set('session.entropy_length', '512');
            session_name($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'))));
        }

        // 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.
        header('Content-type: text/html; charset=' . $this->getParam('character_set'));
        
        // Set the version of the codebase we're using.
        $codebase_version_file = dirname(__FILE__) . '/../docs/version.txt';
        if (is_readable($codebase_version_file)) {
            $codebase_version = trim(file_get_contents($codebase_version_file));
            $this->setParam(array('codebase_version' => $codebase_version));
            header('X-Codebase-Version: ' . $codebase_version);
        }

        $this->running = true;
    }

    /**
     * Stop running this application.
     *
     * @access  public
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   17 Jul 2005 17:20:18
     */
    function stop()
    {
        session_write_close();
        restore_include_path();
        $this->running = false;
        $num_queries = 0;
        if (true === $this->getParam('enable_db')) {
            $num_queries = $this->db->numQueries();
            $this->db->close();
        }
        $this->timer->stop('_app');
        $this->logMsg(sprintf('Script ended gracefully. Execution time: %s. Number of db queries: %s.', $this->timer->getTime('_app'), $num_queries), 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 $line    __LINE__.
     */
    function raiseMsg($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 ('' == trim($message)) {
            $this->logMsg(sprintf('Raised message is an empty string.', __FUNCTION__), LOG_NOTICE, __FILE__, __LINE__);
            return false;
        }

        // 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__);
        }
    }
    
    /**
     * 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
     */
    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
     */
    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.
     *
     * @access  public
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   15 Jul 2005 01:39:14
     */
    function printRaisedMessages()
    {
        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
            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 class="sc-msg-error">' . $m['message'] . '</div>';
                    break;

                case MSG_WARNING:
                    echo '<div class="sc-msg-warning">' . $m['message'] . '</div>';
                    break;

                case MSG_SUCCESS:
                    echo '<div class="sc-msg-success">' . $m['message'] . '</div>';
                    break;

                case MSG_NOTICE:
                default:
                    echo '<div class="sc-msg-notice">' . $m['message'] . '</div>';
                    break;

                }
            }
            ?></div><?php
        }
        $this->clearRaisedMessages();
    }

    /**
     * Logs messages to defined channels: file, email, sms, and screen. Repeated messages are
     * not repeated but printed once with count.
     *
     * @access public
     * @param string $message   The text description of the message.
     * @param int    $priority  The type of message priority (in descending order):
     *                          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
     * @param string $file      The file where the log event occurs.
     * @param string $line      The line of the file where the log event occurs.
     */
    function logMsg($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);
        }

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

        // 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));

        // 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 . $line);
        if (isset($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;
        }

        // Use "lock" files to prevent sending email and sms notices ad infinitum.
        $site_hash = md5($_SERVER['SCRIPT_NAME']);
        $temp_dir = $this->getParam('tmp_dir') . "/codebase_msgs_$site_hash/";
        $temp_file = $temp_dir . md5($file . $line); // Just use the file and line for the msg_id to limit the number of possible messages.
        if (!is_dir($temp_dir)) {
            mkdir($temp_dir);
        }
        $send_notifications = true;
        if (is_file($temp_file)) {
            $msg_last_sent = filectime($temp_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.
                $send_notifications = false;
            } else {
                // Timeout has expired go ahead and send notifications again.
                if (file_exists($temp_file)) {
                    unlink($temp_file);
                }
            }
        } else {
            touch($temp_file);
        }
        
        
        // Data to be stored for a log event.
        $event = array(
            'date'      => date('Y-m-d H:i:s'),
            'remote ip' => getRemoteAddr(),
            'pid'       => (mb_substr(PHP_OS, 0, 3) != 'WIN' ? posix_getpid() : ''),
            'type'      => $this->logPriorityToString($priority),
            'file:line' => "$file : $line",
            'url'       => mb_substr(isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '', 0, 128),
            'message'   => $message
        );

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

        // NOTIFY SOMEONE
        if ($send_notifications) {
            // EMAIL ACTION
            if ($this->getParam('log_email_priority') && $priority <= $this->getParam('log_email_priority')) {
                $subject = sprintf('[%s %s] %s', getenv('HTTP_HOST'), $event['type'], $message);
                $email_msg = sprintf("A %s log event occured on %s\n\n", $event['type'], getenv('HTTP_HOST'));
                $headers = "From: codebase@strangecode.com";
                foreach ($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 ($this->getParam('log_sms_priority') && $priority <= $this->getParam('log_sms_priority')) {
                $subject = sprintf('[%s %s]', getenv('HTTP_HOST'), $priority);
                $sms_msg = sprintf('%s [%s:%s]', mb_substr($event['message'], 0, 64), basename($file), $line);
                $headers = "From: codebase@strangecode.com";
                mb_send_mail($this->getParam('log_to_sms_address'), $subject, $sms_msg, $headers);
            }
        }
    
        // SCREEN ACTION
        if ($this->getParam('log_screen_priority') && $priority <= $this->getParam('log_screen_priority')) {
            echo "[{$event['type']}] [{$event['message']}]\n";
        }

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

    /**
     * Returns the string representation of a LOG_* integer constant.
     *
     * @param int  $priority  The LOG_* integer constant.
     *
     * @return                The string representation of $priority.
     */
    function logPriorityToString($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   $val        The new value of the argument key.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   13 Oct 2007 11:34:51
     */
    function setQuery($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   $default    If the key is not available, set to this default value.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   14 Nov 2005 19:24:52
     */
    function carryQuery($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   $query_key  The key (or keys, as an array) of the query argument to remove.
     * @author  Quinn Comendant <quinn@strangecode.com>
     * @since   18 Jun 2007 20:57:29
     */
    function dropQuery($query_key, $unset=false)
    {
        if (!is_array($query_key)) {
            $query_key = array($query_key);
        }
        foreach ($query_key as $k) {
            if (isset($this->_carry_queries[$k])) {
                // 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[$k])) {
                unset($_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, 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  $always_include_sid  Always add the session id, even if using_trans_sid = true. This is required when
     *                                     URL starts with http, since PHP using_trans_sid doesn't do those and also for
     *                                     header('Location...') redirections.
     *
     * @return string url with attached queries and, if not using cookies, the session id
     */
    function url($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;
        }

        // 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();
            return $url;
        } else {
            $url .= $q;
            return $url;
        }
    }

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

        // Replace any & not followed by an html or unicode entity with it's &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  $carry_args        Additional url arguments to carry in the query,
     *                                   or FALSE to prevent carrying queries. Can be any of the following formats:
     *                                      array('key1', key2', key3')  <-- to save these keys if in the form data.
     *                                      array('key1'=>'value', key2'='value')  <-- to set keys to default values if not present in form data.
     *                                      false  <-- To not carry any queries. If URL already has queries those will be retained.
     */
    function printHiddenSession($carry_args=null)
    {
        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) {
                printf('<input type="hidden" name="%s" value="%s" />', $key, $val);
            }
        }

        // Include the SID if cookies are disabled.
        if (!isset($_COOKIE[session_name()]) && !ini_get('session.use_trans_sid')) {
            printf('<input type="hidden" name="%s" value="%s" />', session_name(), session_id());
        }
    }

    /**
     * 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    $always_include_sid     Force session id to be added to Location header.
     */
    function dieURL($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?
        header(sprintf('Location: %s', $url));
        $this->logMsg(sprintf('dieURL: %s', $url), LOG_DEBUG, __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    $queryless_referrer_comparison   Exclude the URL query from the refererIsMe() comparison.
    * @return   bool                    False if the session is not running. No return otherwise.
    * @author   Quinn Comendant <quinn@strangecode.com>
    * @since    31 Mar 2006 19:17:00
    */
    function dieBoomerangURL($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)) {
            // Ensure that the redirecting page is not also the referrer.
            $url = getenv('HTTP_REFERER');
            $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  $id     An identification tag for this url.
     * FIXME: url garbage collection?
     */
    function setBoomerangURL($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.
        /// FIXME: Why isn't the time set here under setBoomerangURL() and only under dieBoomerangURL()?

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

        $this->logMsg(sprintf('deleteBoomerangURL(%s): %s', $id, $this->getBoomerangURL($id)), LOG_DEBUG, __FILE__, __LINE__);

        if (isset($id) && isset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$id])) {
            unset($_SESSION['_app'][$this->_ns]['boomerang']['url'][$id]);
        } else if (is_array($_SESSION['_app'][$this->_ns]['boomerang']['url'])) {
            array_pop($_SESSION['_app'][$this->_ns]['boomerang']['url']);
        }
    }

    /**
     * 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.
     */
    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.
     */
    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.
     */
    function sslOff()
    {
        if ('' != getenv('HTTPS')) {
            $this->dieURL('http://' . getenv('HTTP_HOST') . getenv('REQUEST_URI'), null, true);
        }
    }


} // End.

?>