On 10 juin, 19:14, mdipierro <mdipie...@cs.depaul.edu> wrote: > Interesting. How do you think this can be implemented?
Well, before thinking about the implementation, we must understand the concepts involved. So let's start with the idea of scope. The scope defines the time a peace of information is kept. Information in application memory is present a certain scope. From the shortest to the longest, scopes form a hierarchy. One scope is included in the life time of another. We may have: - Request scope (exists the time it takes to process the request) - Conversation scope (the time of a conservation) - Session scope (as we already know) - Application scope (from the server start up to its shutdown) - Business process scope (scope usually involving many actors and that can last for many months, this state has to be saved and restored between server shutdowns) The conversation scope deserves more explanation. This is the scope to use for example when a user wants to reserve a hotel room. The user goes through a set of pages to do its reservation (he can also use the back button if he change his mind). He can open a new window and do another reservation in parallel. The application keep a different state for each window. This is what we call a conversation. In the application, we need an object to read and write in these scopes. Let's called it the 'scope resolver' or 'resolver' for short. Instead of using the session, we use the resolver. The resolver looks for a property in the shortest long living scope to find the value of a property. If it does not find the value at one scope, it looks at the next longer living scope. It continues like that up the longest scope. If nothing is found in the whole lookup process, it returns 'None'. To begin and end scoping processes, I think we can use decorators just like Java uses annotations. We also have to find a way to add a hidden field in the forms to identify them with a specific conversation. All of this was implemented in Java using the interceptor pattern. I know that Web2py has the concept of plug-in (I am new to Web2py). Is it possible to implement all this without modifying Web2py? It could a great occasion to improve the design of the framework if it is not the case. We have a great example with JBoss Seam. Spring Webflow could be inspiring too. So before going in the details, what do think about this idea?
