root --+
       |
       +--- client page
       |
       +--- email page

##</code><code>##

Vlad --> 
     Node: /root
     Permission: 'All'

Bill --> 
     Node: /root/client page
     Permission: 'View'

Joe  -->
     Node: /root/client page
     Permission: 'Edit', 'View'

Sam  -->
     Node: /root/email page
     Permission: 'All'

##</code><code>##

use GUMS;
# initialize DBI database...

# you retrieve user name from a cookie or
# database here...

# now, veirfy permissions:
my $res = GUMS::verify_user_perm(
               dbh => $dbh,
               app_name => 'client_management_tool',
               node_path => "/root/$app_page",
               user_name => $user_name,
               perm => 'Edit'
             );

unless ($res) {
   print "$user_name lacks 'Edit' permission to access/use this page.\n";
}

##</code><code>##

# Under Construction