Control of the number of clients that access to a web application (application that sells tickets)

I attach an iRule.

 

 

We have a web application used for buying tickets. Before the web server, there is a load balancer. The clients connect to the virtual server and it sends the requests to the above server.

 

 

But…We have to be careful, because the number of clients can not be bigger of a number. Because of that, this iRule, is used to count the number of new clients connected to the web server. If the number of clients is bigger than the maximum permitted, we have to send the client to a “sorry page”. We need a redirection.

 

 

 

 

We have used COOKIES for this iRule. The loadbalancer inserts cookies to the new clients connected and checks the timeouts in order to see if the connection has to be renewed (and increment the counter of clients) or not.

 

 

 

 

I arrach you the iRule flow and syntax. Could anybody help me?