# Application helper problema **URL:** \ **Category:** Rails\ **Created:** [February 7, 2009, 7:17am UTC](https://www.ruby-forum.com/t/application-helper-problema/159694 "2009-02-07T07:17:24Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![bigdaddy71](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bbe5ce/32.png) [@bigdaddy71](https://www.ruby-forum.com/u/bigdaddy71)\ **Post date:** [February 7, 2009, 7:17am UTC](https://www.ruby-forum.com/t/application-helper-problema/159694/1 "2009-02-07T07:17:24Z")
I am calling a function I made in application\_helper but when I try to call it it keeps saying method undefined. If I put the function in the controller it runs just fine. any ideas? ---
**Author:** ![bigdaddy71](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bbe5ce/32.png) [@bigdaddy71](https://www.ruby-forum.com/u/bigdaddy71)\ **Post date:** [February 7, 2009, 8:30am UTC](https://www.ruby-forum.com/t/application-helper-problema/159694/2 "2009-02-07T08:30:34Z")
did you mean when you put it in your controller’s helper file, it works? make sure you are using your helpers in your views, and not in your controller. Chris H. wrote: > I am calling a function I made in application\_helper but when I try to > call it it keeps saying method undefined. If I put the function in > the controller it runs just fine. any ideas? ---
**Author:** ![bigdaddy71](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bbe5ce/32.png) [@bigdaddy71](https://www.ruby-forum.com/u/bigdaddy71)\ **Post date:** [February 7, 2009, 9:09am UTC](https://www.ruby-forum.com/t/application-helper-problema/159694/3 "2009-02-07T09:09:05Z")
Should have used Hamburger Helper. I think application.rb doesn’t reload unless you restart the server. Maybe application\_helper is the same way and it looks like this post agrees: [Plugins - helper function is an "undefined method", Objects "can't be referred" - Rails - Ruby-Forum](http://www.ruby-forum.com/topic/155700) On Fri, Feb 6, 2009 at 11:30 PM, Eddie S. \ wrote: > > the controller it runs just fine. any ideas? > > – > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). > > > – Available for Ruby on Rails development opportunities ---
**Author:** ![bigdaddy71](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bbe5ce/32.png) [@bigdaddy71](https://www.ruby-forum.com/u/bigdaddy71)\ **Post date:** [February 7, 2009, 10:51am UTC](https://www.ruby-forum.com/t/application-helper-problema/159694/4 "2009-02-07T10:51:28Z")
That sounds strange. All controllers reload, therefore application controller does too, because it’s an abstract class. Blog: [http://random8.zenunit.com/](http://random8.zenunit.com/) Learn rails: [http://sensei.zenunit.com/](http://sensei.zenunit.com/) ---
**Author:** ![bigdaddy71](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bbe5ce/32.png) [@bigdaddy71](https://www.ruby-forum.com/u/bigdaddy71)\ **Post date:** [February 7, 2009, 7:28pm UTC](https://www.ruby-forum.com/t/application-helper-problema/159694/5 "2009-02-07T19:28:44Z")
OK, so you can only call functions in a controller that are in a model? I have an app that does not have a model but I guess I can create one if need be. ---
**Author:** ![bigdaddy71](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bbe5ce/32.png) [@bigdaddy71](https://www.ruby-forum.com/u/bigdaddy71)\ **Post date:** [February 7, 2009, 10:50am UTC](https://www.ruby-forum.com/t/application-helper-problema/159694/6 "2009-02-07T10:50:17Z")
Where are you trying to call it from? Helpers are for views Blog: [http://random8.zenunit.com/](http://random8.zenunit.com/) Learn rails: [http://sensei.zenunit.com/](http://sensei.zenunit.com/) On 07/02/2009, at 6:30 PM, Eddie S. \ **Author:** ![bigdaddy71](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bbe5ce/32.png) [@bigdaddy71](https://www.ruby-forum.com/u/bigdaddy71)\ **Post date:** [February 7, 2009, 10:38pm UTC](https://www.ruby-forum.com/t/application-helper-problema/159694/7 "2009-02-07T22:38:29Z") On Feb 7, 1:28 pm, Me [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > OK, so you can only call functions in a controller that are in a > model? You can call methods from pretty much anywhere, but that is not the point. In Rails, you want to follow their MVC pattern to get the most of the framework.You want to call methods within the scope of where you are at. The browser requests go from Dispatcher → Controller → View The purpose of the controller is to get the request, maybe validate the user, then instantiate an object that will be rendered in the view. That’s it. Any logic about the specifics of how to instantiate the object should be handled by the model classes. So in that part, you are correct when you say “only call functions in a controller that are in a model”. You are making a call to instantiate an object that will be used in the view. The model classes usually have a database back end but it does not have to be. It is common to have model classes for specialized reports for example, that have aggregation methods, etc. So you should create a model class for what you are trying to do, to separate those methods in their own domain. Finally, the purpose of the Helper classes is to provide methods for the View. When you need to format something, etc. you put call methods in either the controller\_helper class or the generic application helper class. Hope that helps.