# Put code in model or controller. Any general rules of thumb? **URL:** \ **Category:** Rails\ **Created:** [January 9, 2007, 3:59am UTC](https://www.ruby-forum.com/t/put-code-in-model-or-controller-any-general-rules-of-thumb/81464 "2007-01-09T03:59:21Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![pervel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/7bcc69/32.png) [@pervel](https://www.ruby-forum.com/u/pervel)\ **Post date:** [January 9, 2007, 3:59am UTC](https://www.ruby-forum.com/t/put-code-in-model-or-controller-any-general-rules-of-thumb/81464/1 "2007-01-09T03:59:21Z")
I am a Rails newbie (but far from a programming newbie). I have taken perhaps a strange path to learning Rails. I started getting experience with Ruby - lovely language indeed! Then I ventured into ActiveRecord. Slick and easy to understand framework. Now, I am starting on the controllers. But that gives me some doubts. I am constantly wondering if I have bloated my models with too much code. So I would like to ask if there is perhaps a write-up somewhere about what to consider when deciding between putting code in the model or in the controller? When I get to learning about the views, I will probably wonder about the same issue. I understand that the rule of thumb here is basically to put as little code in the view as possible. So again that leads back to the question of putting the code to support the views in the model or the controller. I know these are pretty general questions. And I am certainly not looking for a “fact book”. Just some insight into how other people tend to make their decisions about where to put the code. 🙂 ---
**Author:** ![pervel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/7bcc69/32.png) [@pervel](https://www.ruby-forum.com/u/pervel)\ **Post date:** [January 9, 2007, 4:25am UTC](https://www.ruby-forum.com/t/put-code-in-model-or-controller-any-general-rules-of-thumb/81464/2 "2007-01-09T04:25:03Z")
Per V. wrote: > I am a Rails newbie (but far from a programming newbie). I have taken > perhaps a strange path to learning Rails. I started getting experience > with Ruby - lovely language indeed! Then I ventured into ActiveRecord. > Slick and easy to understand framework. > > Now, I am starting on the controllers. But that gives me some doubts. I > am constantly wondering if I have bloated my models with too much code. > So I would like to ask if there is perhaps a write-up somewhere about > what to consider when deciding between putting code in the model or in > the controller? > > When I get to learning about the views, I will probably wonder about > the same issue. I understand that the rule of thumb here is basically > to put as little code in the view as possible. So again that leads back > to the question of putting the code to support the views in the model > or the controller. > > I know these are pretty general questions. And I am certainly not > looking for a “fact book”. Just some insight into how other people tend > to make their decisions about where to put the code. 🙂 This helped me : [http://weblog.jamisbuck.org/2006/10/18/skinny-controller-fat-model](http://weblog.jamisbuck.org/2006/10/18/skinny-controller-fat-model) ---
**Author:** ![pervel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/7bcc69/32.png) [@pervel](https://www.ruby-forum.com/u/pervel)\ **Post date:** [January 9, 2007, 6:52am UTC](https://www.ruby-forum.com/t/put-code-in-model-or-controller-any-general-rules-of-thumb/81464/3 "2007-01-09T06:52:32Z")
On 1/3/07, Per V. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I am a Rails newbie (but far from a programming newbie). So am I so take the rest of the mail with a pinch of salt. 🙂 > So again that leads back > to the question of putting the code to support the views in the model > or the controller. when I started my first RoR app, views were pretty fat, after my first iteration I moved most of the code to controller, now in my second iteration I am moving things to model as much as possible. My rule of thump is that you should not be using Model.find() in your controller. Write helper methods in your model to get the data in the form you want. That will lead to more consistency and leaner controller. But take care not to take this to insane levels 🙂 Also checkout this blog post for more details from some one with more clue than me. [http://weblog.jamisbuck.org/2006/10/18/skinny-controller-fat-model](http://weblog.jamisbuck.org/2006/10/18/skinny-controller-fat-model) raj ---
**Author:** ![pervel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/7bcc69/32.png) [@pervel](https://www.ruby-forum.com/u/pervel)\ **Post date:** [January 9, 2007, 4:11pm UTC](https://www.ruby-forum.com/t/put-code-in-model-or-controller-any-general-rules-of-thumb/81464/4 "2007-01-09T16:11:21Z")
Sheldon H. wrote: > You’re asking the right questions. 🙂 > > It took me a long time to settle on a simple decision process that > works for me, especially in the J2EE environment where it’s not as easy > to change your mind. Sheldon, Your entire response was great! I really enjoyed reading it and I don’t believe anyone could have said it any better… Thankfully I have no scruples, so I will simply steal yours and next time I get this question, I will be sure to impress! 🙂 ilan ---
**Author:** ![pervel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/7bcc69/32.png) [@pervel](https://www.ruby-forum.com/u/pervel)\ **Post date:** [January 9, 2007, 8:04am UTC](https://www.ruby-forum.com/t/put-code-in-model-or-controller-any-general-rules-of-thumb/81464/5 "2007-01-09T08:04:38Z")
You’re asking the right questions. 🙂 It took me a long time to settle on a simple decision process that works for me, especially in the J2EE environment where it’s not as easy to change your mind. I default to trying to push code down into the model. However, I ask myself these two questions: 1. Does this code describe anything other than behavior of this model? 2. Does this code know about CGI or HTML? If the answer to either of those questions is yes, I look more seriously at putting the code in the controller or an helper. If the answer is “yes and no”, I’m probably trying to do too much at once, and need to break it up across the layers. In summary, favor the model, but not at the cost of layering violations. The attitude that this comes from is that your domain model (your collection of “models”) is the system. The controller is only there to mediate a view into it. This attitude works well for the kinds of applications Rails is suited to. Here are two more considerations: 1. Code that you put in the model is easy to use from the Rails console and runner. Code that’s in the controller is more of a pain in the arse to get to. 2. Model instances can call each others’ methods, but they can’t call methods on controllers without jumping through hoops. Ciao, Sheldon.