Hi all, Following up on the best practices series, what is the best way to do some more advanced model validation, beyond presence, numericality, etc. For example, I want to do some checks on the database to see if a user has performed a certain action before (such as joining a group), and then pass the appropriate error messages back to the controller? Having followed the best practices to move as much logic out of the controller and into the model, I have created a function Group.add_user(user) that checks for existing membership in the group, and then makes the association. However, I'd like to be able to pass an error message back into the flash notice if the user has already joined the group. I can think of two ways of doing this... 1. In controller: if group.check_ownership(user) Group.add_user(user) else flash[:notice] = "error message" end I don't like this method, because it seems to be putting logic back into the controller; this logic could get more complex outside of this simple example. 2. In Group model: def add_user if !group.check_ownership(user) Group.add_user(user) else return "error message" # or return an error number end end 3. Write a validator? A brief read in DHH's book seems to suggest validators are more for checking database content than for things like checking associations. Is there a better method? Any help much appreciated!
on 2009-03-01 00:15