Source for file BrowseHistoryManager.class.php

<?php
 
/**
 * Keeps track of the last important page the user visited, and returns them there
 * when called upon to do so.
 *
 * @package harmoni.architecture
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: BrowseHistoryManager.class.php,v 1.7 2007/09/04 20:25:30 adamfranco Exp $
 ***/
 
class BrowseHistoryManager {
 
    /**
     * Marks the current return-point after an operation has completed. The
     * function can take three forms:
     * 
     * void markReturnURL(string $op)                    - takes the current URL from Harmoni::request
     * void markReturnURL(string $op, string $url)        - take a URL as a string
     * void markReturnURL(string $op, URLWriter $obj)    - takes a {@link URLWriter} object and creates
     *                                                        the URL from that
     *
     * @return void 
     * @param string $operation The label (or operation) under which to store the URL.
     *                              Later, a script may call goBack($operation) to return
     *                              the browser to this URL.
     * @param optional mixed $arg Either a string, an object ({@link URLWriter}), or nothing.
     * @access public
     */
    function markReturnURL($operation, $arg = null) {
        $url = '';
        if ($arg == null) {
            $harmoni = Harmoni::instance();
            $urlObj =$harmoni->request->mkURLWithPassthrough();
            $url = $urlObj->write();
        } else if (is_string($arg))
            $url = $arg;
        else if (is_object($arg)) 
            $url = $arg->write(); // a URLWriter object
        
        
        $_SESSION['__returnURL'][$operation] = $url;
//        print "for operation: $operation -- $url <br>";
    }
    
    /**
     * Sends the browser to the last URL marked with {@link BrowseHistoryManager::markReturnURL markReturnURL()}.
     * @param string $operation The name of the operation under which the URL
     *  is stored.
     * @return void 
     * @access public
     */
    function goBack($operation) {
        RequestContext::sendTo($this->getReturnURL($operation));
        exit();
    }
    
    /**
     * Answer a marked url
     * 
     * @param string $operation The name of the operation under which the URL
     *  is stored.
     * @return object URLWriter 
     * @access public
     * @since 6/7/05
     */
    function getReturnURL($operation) {
        if (isset($_SESSION['__returnURL'][$operation])) {
            $url = $_SESSION['__returnURL'][$operation];
        } else {
            $harmoni = Harmoni::instance();
            $url = $harmoni->request->quickURL(
                $harmoni->config->get("defaultModule"),
                $harmoni->config->get("defaultAction")
            );
        }
        return $url;
    }
}
 
?>