Extending a model outside of its file

Rails
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?

–
Phlip
Test Driven Ajax (on Rails) [Book]
“Test Driven Ajax (on Rails)”
assert_xpath, assert_javascript, & assert_ajax

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

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!

5

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