extension.driver.php

<?php

	class extension_multi_user_edit extends Extension {
	/*-------------------------------------------------------------------------
		Definition:
	-------------------------------------------------------------------------*/

		public static $active = true;

		public function getSubscribedDelegates() {
			return array(
				array(
					'page'		=> '/publish/edit/',
					'delegate'	=> 'EntryPreRender',
					'callback'	=> 'preRender'
				),
				array(
					'page'		=> '/publish/edit/',
					'delegate'	=> 'EntryPostEdit',
					'callback'	=> 'postEdit'
				)
			);
		}

		public function install(){
            try{
                Symphony::Database()->query("
                    CREATE TABLE IF NOT EXISTS `tbl_multi_user` (
                        `id` int(11) unsigned NOT NULL auto_increment,
                        `user_id` int(11) unsigned NOT NULL,
                        `entry_id` int(11) unsigned NOT NULL,
                        `session_start` DATETIME() unsigned NOT NULL,
                        PRIMARY KEY  (`id`),
                        KEY `entry_id` (`entry_id`)
                    ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
                ");
            }
            catch(Exception $e){
                return false;
            }

            return true;
        }

		public function enable(){
			return $this->install();
		}

		public function preRender($context) {
			
			$entry_id = $context['entry']->get('id');

			//Check if the entry id is already created in the table.

			$query = "SELECT count(multi.entry_id) as count 
			 			FROM tbl_multi_user as multi
			 			WHERE multi.entry_id = '". $entry_id ."'";

            $count = Symphony::Database()->fetchVar('count',0,$query);

            if ($count == 0){
            	//Add the entry id to the database. Adding 0 as a temporary value for author.
				 $query = "INSERT INTO tbl_multi_user (user_id, entry_id)
							VALUES ('0', $entry_id)";

	            if(Symphony::Database()->query($query) == TRUE){
	            	return true;
	            }

	            return false;
            }
            else{
            	//Entry is already in DB.
            }

            //Add JS to the page.
			Administration::instance()->Page->addScriptToHead(URL . '/extensions/multi_user_edit/assets/js/multi_user.js', 3134);

			
		}

		public function postEdit($context) {
			$entry_id = $context['entry']->get('id');

			//Release lock.
			$update = array();
			$update['user_id'] = intval('0');
			$update['session_start'] = date('0');

			Symphony::Database()->update($update, 'sym_multi_user', "`entry_id` = ".$entry_id);

		}
	}