Question

I’ve finished a personal project now just going through my code cleaning things up. I’m wondering if methods that help find things in the database belong in the model?

E.g.

This was in my controller:

@user = User.find_by_username(username)

I then moved it to my model:

class << self
    def find_user_by_username(username)
      User.find_by_username(username)
    end

end

added this to my controller:

@user = find_user_by_username(username)

Is there anything wrong with this? does it really matter if I have find, where and other methods that help find things in my controller? What about putting them in helpers?

Another thing is I tried to call that same method in a show action and pass in params with a users username as the value. I get:

undefined method `find_user_by_username' for #<UsersController:0x000001034a6060>

I just want to clean up but not break things. I don’t understand why that method would work fine in my new action but not in show action.

Thanks in advance

kind regards

Answer 1

In a good design, you want to have the skinniest controller possible, and that means moving a maximum of code from the controlelr to the model. Then, if your model become too large, there are other technique to move code down the model to other layers (libs, observers, etc).

The find_by_* method is already in the model but it his a class method. So it’s perfectly reasonable to call it from your controller.

If your search was not a simple find but , let’s say, a search by user.username or user.company.name , then you would probably have to make that search method in the model and call it from your controller.

This way also allows you to call that method from different controller instead of copy/paste-ing it

More info on where to put your code can be found here : http://qualityonrails.com/archives/33