where to put controller code for partials you render from different views in Ruby on Rails

Question

A newbie question:

I have a partial that I'm loading on a website on different pages.

That partial needs some data, so in the controller of the parent view I do the query: @properties = Property.find(:all)

I pass the query results to the partial in the view using :locals

Now, I would like to render the same partial from another view. This view has a different controller. Do I have to repeat the query in that controller also? Or can I have a separate controller for partials I use one more places in the website. In this last case, how do I indicate which controller to use in the view when I put the render command?

Or should I use somethink different than partials for this kind of use?

Kind regards, Michael

Answer 1

You don't need to copy the code to set up the partial's data, but you would need to hoist it into a controller that your two controllers inherit from. Normally, this would be your ApplicationController. Define a method in there that loads the data you need. For example:

class ApplicationController < ActionController::Base
  # ... your code ...

protected

  def load_partial_data
    @properties = Property.find(:all)
  end

end

Now to actually call this method you have two options:

1. If all your controllers need this data, add a before_filter to your ApplicationController like before_filter :load_partial_data
2. Otherwise, add the before_filter to just the controllers that actually need to load the data.

I hope this helps.

Answer 2

How i would solve this, is to define a new file inside your lib folder, with a meaningful name. For now i will just use does_as_shared.rb:

module DoesAsShared
  def setup_shared_data
    @shared_data = ...do something useful here ...
  end
end

and then inside your controllers that need that code you write:

class ThingsController < ApplicationController
  include DoesAsShared

  def index
    setup_shared_data
    .. and do some more stuff ...
  end
end

The advantage of this code is that the shared code is limited to those controllers that really need it. And at the same time it is pretty readable: the include statement, given that the name is chosen well, clearly indicates what functionality is included.