extending a model outside of its file

rubyonrails-talk
1

Hello.

I'm wondering how to add methods to a model (stored in /app/models) from a ruby file located in /lib/my-extension for instance. How is it possible? Are the models of an app stored in a specific ruby module?

Thanks.

aurels

2

Aurels wrote:

I'm wondering how to add methods to a model (stored in /app/models) from a ruby file located in /lib/my-extension for instance. How is it possible? Are the models of an app stored in a specific ruby module?

Classes often must extend in the correct order. Maybe the ./app/models version must interpret before the ./lib version. If so, the top of ./lib/my_model.rb should say require RAILS_ROOT + '/app/models/my_model', to get the correct one.

Otherwise, the top of ./app/models/my_model could likewise require the ./lib version.

But this opens the question why not put everything in one model?

Either way, the "magic loader" system (aka "autorequire") will hide your app/model version if any interpretation sees the ./lib version first. The MyModel class name will be satisfied, and not trigger an auto-require. You must require the explicit app/model version at the top of any .rb file that you expect to correctly see it.

Now, why are you trying to do this?

3

Thanks for your reply

Now, why are you trying to do this?

I want to separate a complicated method outside of the model and to be able to "desactivate" it easily...

4

More simply, isn't it possible to define a class in two INDEPENDANT files?

e.g.,

file1.rb: class A   def m ; end end

file2.rb class A   def n; end end

and I want    - A to have the method m if only file1.rb was loaded    - A to have the method n if only file2.rb was loaded    - A to have both m and n if the two files were loaded

5

I finally found my way out using a module and an include. It's not completely independent but better than putting everything in the same place!