PHP User Group Levels - php

Question

I am working on a small cms project my database fields are as follows
Levels Table
CREATE TABLE IF NOT EXISTS `security_level` (
`user_level` int(10) NOT NULL,
`level_title` varchar(30) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
VALUES
1, User
2, Moderator
3, Administrator
User table
CREATE TABLE IF NOT EXISTS `users` (
`uid` int(11) unsigned NOT NULL,
`username` varchar(25) NOT NULL,
`user_email` varchar(255) NOT NULL,
`password` text,
`security_level` int(11) NOT NULL DEFAULT '1',
) ENGINE=MyISAM DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;
What I am trying to do is create a function that I can include on my member area pages, so if there level_id is 1 but the page requires level_id 2 it will simply redirect them, by default the level is set to 1...
I am using this to make sure they are logged in or redirect
<?php
if (logged_in()) {} else {
redirect("login.php");
}
?>
but I would like to restrict access to certain pages based on level_id

Answer 1

A simple way to do it would be something like this. The function below returns true or false and takes 2 arguments: $page_level and $user_level:
function user_has_permissions($user_level, $page_level)
{
// a user can access page less than or equal to their level
if ((int)$user_level >= (int)$page_level)
{
return true;
}
else
{
return false;
}
}
I am calling this function user_has_permissions() and not logged_in() because the user might be logged in but they may not have permissions to a page that belongs to a different level.
Then on the page, in order to user this function.
$page_level = "2"; // define page level on each page
// get the user level from sessions
if (!user_has_permissions($_SESSION['user_level'], $page_level))
{
header ("Location: login.php");
exit;
}
// code after successful permissions checking goes here
This is a simple implementation but you are probably looking for something like Access Control Lists (ACL).