<?php
/* Reminder: always indent with 4 spaces (no tabs). */
// +---------------------------------------------------------------------------+
// | Copyright (c) 2008, Demian Turner                                         |
// | All rights reserved.                                                      |
// |                                                                           |
// | Redistribution and use in source and binary forms, with or without        |
// | modification, are permitted provided that the following conditions        |
// | are met:                                                                  |
// |                                                                           |
// | o Redistributions of source code must retain the above copyright          |
// |   notice, this list of conditions and the following disclaimer.           |
// | o Redistributions in binary form must reproduce the above copyright       |
// |   notice, this list of conditions and the following disclaimer in the     |
// |   documentation and/or other materials provided with the distribution.    |
// | o The names of the authors may not be used to endorse or promote          |
// |   products derived from this software without specific prior written      |
// |   permission.                                                             |
// |                                                                           |
// | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS       |
// | "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT         |
// | LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR     |
// | A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT      |
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// | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE     |
// | OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.      |
// |                                                                           |
// +---------------------------------------------------------------------------+
// | Seagull 0.6                                                               |
// +---------------------------------------------------------------------------+
// | AjaxProvider.php                                                          |
// +---------------------------------------------------------------------------+
// | Author: Julien Casanova <julien@soluo.fr>                                 |
// +---------------------------------------------------------------------------+

define('SGL_RESPONSEFORMAT_JSON', 1);
define('SGL_RESPONSEFORMAT_PLAIN', 2);
define('SGL_RESPONSEFORMAT_JAVASCRIPT', 3);
define('SGL_RESPONSEFORMAT_HTML', 4);
define('SGL_RESPONSEFORMAT_XML', 5);

/**
 * Abstract model controller for all the 'ajax provider' classes.
 *
 * @package SGL
 *
 * @author Julien Casanova <julien@soluo.fr>
 * @author Dmitri Lakachauskis <lakiboy83@gmail.com>
 *
 * @abstract
 */
class SGL_AjaxProvider
{
    /**
     * Holds configuration
     *
     * @var array
     */
    var $conf = array();

    /**
     * DB abstract layer
     *
     * @var DB resource
     */
    var $dbh = null;

    /**
     * Constant indicating response format.
     *
     * @var integer
     */
    var $responseFormat = SGL_RESPONSEFORMAT_HTML;

    /**
     * Constructor.
     *
     * @access public
     */
    function SGL_AjaxProvider()
    {
        SGL::logMessage(null, PEAR_LOG_DEBUG);

        $c = &SGL_Config::singleton();
        $this->conf = $c->getAll();
        $this->dbh = $this->_getDb();
    }

    function &_getDb()
    {
        $locator = &SGL_ServiceLocator::singleton();
        $dbh = $locator->get('DB');
        if (!$dbh) {
            $dbh = &SGL_DB::singleton();
            $locator->register('DB', $dbh);
        }
        return $dbh;
    }

    /**
     * Main routine of processing ajax requests.
     *
     * @param SGL_Registry $input
     * @param SGL_Output $output
     *
     * @return mixed
     */
    function process(&$input, &$output)
    {
        SGL::logMessage(null, PEAR_LOG_DEBUG);

        $req = $input->getRequest();
        $actionName = $req->getActionName();

        // handle errors
        if (SGL_Error::count()) { // eg, authentication failure
            return;
        } elseif (!method_exists($this, $actionName)) {
            SGL::raiseError('requested method does not exist');
            return;
        }
        // by default request is authorised
        $ok = true;

        // only implement on demand
        $providerContainer = ucfirst($req->getModuleName()) . 'AjaxProvider';
        if (!empty($this->conf[$providerContainer]['requiresAuth'])
                && $this->conf['debug']['authorisationEnabled']) {
            $aMethods = explode(',', $this->conf[$providerContainer]['requiresAuth']);
            $aMethods = array_map('trim', $aMethods);
            if (in_array($actionName, $aMethods)) {
                $resourseId = $this->getAuthResourceId();
                $ok = $this->isOwner($resourseId, SGL_Session::getUid());
            }
        }
        if (!$ok) {
            SGL::raiseError('authorisation failed', SGL_ERROR_INVALIDAUTHORISATION);
            return;
        }
        $output->data = $this->$actionName();
    }

    /**
     * Authorisation routine.
     *
     * @param mixed $resourseId
     * @param integer $userId
     *
     * @return boolean
     *
     * @abstract
     */
    function isOwner($resourseId, $userId)
    {
        return true;
    }

    /**
     * Get resource ID.
     *
     * @return mixed
     *
     * @abstract
     */
    function getAuthResourceId()
    {
        return 'resourceId';
    }

    function jsonEncode($data)
    {
        if (function_exists('json_encode')) {
            $ret = json_encode($data);
        } else {
            require_once 'HTML/AJAX/JSON.php';
            $json = new HTML_AJAX_JSON();
            $ret = $json->encode($data);
        }
        return $ret;
    }

    function handleError($oError)
    {
        $aResponse = array(
            'message'   => $oError->getMessage(),
            'debugInfo' => $oError->getDebugInfo(),
            'level'     => $oError->getCode(),
            'errorType' => SGL_Error::constantToString($oError->getCode())
        );

        $ret = SGL_AjaxProvider::jsonEncode($aResponse);
        return $ret;
    }
}
?>