Extending a controller in Rails

Question

I have a controller which calls out to another class.

class BlahController < ActionController
  def index
    OtherClass.get_stuff
  end
end

In this class I want to be able to write controller style code.

for instance:

class OtherClass
  def self.get_stuff
    @foo = bar
  end
end

However, I would also like @foo to exist when inside my view, but as it's a separate class those variables aren't making it back through into the controller assigns - so question is, how I can make this so?

(Ignore why I'm having to call out to a separate class, I'm trying to get this code fitting in with a legacy codebase without too much butchery)

are you dealing with lots of instance variables, if not simple return from your class and storing it in instance variable should be good to go — Ross, Oct 15 '12 at 13:13
I don't want to return stuff as it limits what I can do with the class later on — Neil Middleton, Oct 15 '12 at 13:14
How about you move your method - OtherClass.getStuff to a helper class so that it is accessible from view ? — royalghost, Oct 15 '12 at 13:23
Helpers are primarily view helpers, not controller and I don't really want to dirty those waters. — Neil Middleton, Oct 15 '12 at 13:24
You are confused. There is no such thing as "controller style code". A controller is just a class. You're asking to set an instance variable from the return value of a method in another class. See my answer. — Daniel Szmulewicz, Oct 15 '12 at 13:46
Does OtherClass has to be a class? What if you change OtherClass to a module and mix in it into the controller? — Yanhao, Oct 15 '12 at 14:38

score 1 · Answer 1 · answered Oct 15 '12 at 13:33

class BlahController < ActionController
  def index
    OtherClass.get_stuff(self)
  end
end

class OtherClass
  def self.get_stuff(that)
    that.instance_variable_set(:@foo, bar)
  end
end

Please note that I don't agree with this method. I am just answering the question as you stated it.

I would prefer to accomplish this functionality through mixins and thereby decrease parameter coupling that is present within the code above.

score 0 · Answer 2 · answered Oct 15 '12 at 13:52

Code structured like this will be difficult to read and maintain. Whenever you can, let the controller directly set all of the variables that the view needs:

class BlahController < ActionController
  def index
    @foo = OtherClass.get_stuff
  end
end

class OtherClass
  def self.get_stuff
    # return the value that should be assigned to @foo  
  end
end

Extending a controller in Rails

2 Answers2