File: users-online.php

<?

class users_online {

	var $s_host     = DATABASE_HOST;		//	host
	var $s_username = DATABASE_USER;		//	username
	var $s_password = DATABASE_PASSWORD;		//	password
	var $s_database = DATABASE_NAME;		//	database name 

	var $s_db_link;

	var $n_secs = 86400;		        //	seconds to timeout now set to 24 hours because old logins will be deleted


	function users_online ( $n_ip ) {

		$this->n_ip = $n_ip;

		$this->s_db_link = mysql_connect ( $this->s_host, $this->s_username, $this->s_password );
		mysql_select_db ( $this->s_database );

	}

	//
	//	main
	//
	//		calls the necessary functions in the correct order to get the desired results
	//

	function main () {
		$this->ipclean ();

		if ( $this->is_logged ()  ) {
			$this->clean ();
		}
		else {
			$this->new_user ();
		}
		$this->clean ();
	}

	//
	//	new_user
	//
	//		inserts a user into the database
	//

	function new_user () {
		$timestamp = time ();
		$sql = "insert into users_online ( id, ip, timestamp ) values ( '', '$this->n_ip', '$timestamp' )";
		mysql_query ( $sql, $this->s_db_link );
	}

	//
	//	is_logged
	//
	//		checks if a user is already in the database.
	//

	function is_logged () {
		$sql = "select * from users_online where ip = '" . $this->n_ip . "'";
		if ( mysql_num_rows ( mysql_query ( $sql, $this->s_db_link ) ) > 0 ) {
			return 1;
		}
		else {
			return 0;
		}
	}

	//
	//	clean
	//
	//		deletes "timeouted" users from the database
	//

	function clean () {
		$n_now = time ();
		$sql = "delete from users_online where timestamp < ( $n_now - $this->n_secs )  and ip = '$this->n_ip' ";
		mysql_query ( $sql );
	}

	function ipclean () {
		$n_now = time ();
		$sql = "delete from users_online where ip = '$this->n_ip' ";
		mysql_query ( $sql );
	}

	//
	//	update
	//
	//		updates timestamp value in the database for the active user
	//

	function update () {
		$timestamp = time ();
		$sql = "update users_online set timestamp = $timestamp where ip = '$this->n_ip'";
		mysql_query ( $sql );
	}

	//
	//	count
	//
	//		returns the number of users in the database at runtime

	function count () {

		$sql = "select * from users_online ";
		$count = mysql_num_rows ( mysql_query ( $sql, $this->s_db_link ) );
		return $count;
	}

}

?>