Question : How to implement Zend Framework service layer and acl?

I've been struggling with the best way to implement a service layer in Zend Framework as well as integrating this service layer with a dynamic ACL. I realize that implementation depends on the business logic at hand, but I'm looking for some general recommendations. I'm building a sales application with the following components:

 - Purchase Orders (Salesperson creates and manages purchase orders)
 - Sales (Salesperson generates sales)
 - Warehouse (Receive equipment from purchase orders)
 - Audit (Audit equipment from purchase orders, returned sales, etc.)
 - etc, etc.

Below is my current structure:

 - Models directory under /application to store Doctrine 2.0 entity and repository classes
 - Each module stored under /application/modules with its own forms, services, controllers, views. Note that the models are only stored on the top level, as I'm not sure how to configure Doctrine 2.0 Entities to reside in different folders.

My questions are as follows:

 1. I'm not sure using modules is the best approach. Certain groups of people will have access to certain modules in the application, so this is correct from a permissions standpoint. However, I find that having services in each module is confusing, as most of these services are used across all modules. What is a good approach to structuring this application?

 2. In using a service layer pattern, should I have a service for each model? How about services which do not correspond to a given model?

 3. Would it be better to organize all forms, services at a global level along with the models?

 4. Finally, what is the best structure for permissions in this case? Should I put the acl down into the service classes? Or should I control access at the controller level?

Thank you for any suggestions.

Answer : How to implement Zend Framework service layer and acl?

Hello somersetit,

1_ A service layer in your case should provide a thin facade to your domain model to provide an interface for your service layer clients. How you organize your domain model objects is really up to you but it would make sense to keep it simple as possible.

2_ Very often there is a one to one mapping between these  and again this would make your like easier.

3_ I like using forms that live at the top level of the application and have written classes that can dynamically generate these for models based on table gateways and information stored about them.

4_ I look at ACL as a way to implement business rules over resources for access by clients (A Model).  Keeping the service layer as thin as possible comes back to my first point. You call the ACL from your controllers to determine if a client which has an assigned role has the required permission to to the requested resource and act appropriately,

I hope this helps.

Joseph Melnick