How can user permissions be managed dynamically in PHP to restrict access to certain pages or data based on user roles?

User permissions can be managed dynamically in PHP by assigning roles to users and checking those roles before granting access to certain pages or data. This can be achieved by storing user roles in a database and checking the user's role against the required role for a particular page or data. By implementing role-based access control, you can restrict access to certain parts of your application based on the user's role.

// Check user role before granting access to a page
$userRole = getUserRoleFromDatabase(); // Function to retrieve user role from database
$requiredRole = 'admin'; // Define the required role for accessing the page

if($userRole !== $requiredRole){
    // Redirect user to an error page or display an error message
    header('Location: error.php');
    exit();
}

// Page content for users with the required role
echo "Welcome, admin!";