Call rendering from another controller

Question

I have a rails application with 3 controllers :

categories, subcategories, all

The two firsts fetch data from the db and render it via

render "list"

The last one should get the result of the first controller, the result of the second one and render them.

Simplified example :

# categories_controller.rb
class CategoriesController < ApplicationController
    def index
        render "list"
    end
end 

# subcategories_controller.rb
class SubcategoriesController < ApplicationController
    def index
        render "list"
    end
end 

# all_controller.rb
class AllController < ApplicationController
    def index
        # should render the both and join them
    end
end 

# list.html.erb
this is the list 

Result :

/category
=> "this is the list "

/subcategory
=> "this is the list "

/all
=> "this is the list this is the list "

I tried to call

 render "subcategory"
 render "subcategory/index"

But nothing seems to work.

Do you have an idea?

Thanks,

---

A previous approach was the following :

# categories_controller.rb
class CategoriesController < ApplicationController
    def self.getAll
        return Category.all
    end
    def index
        @data = CategoriesController.getAll
        # some logic here
        render "list"
    end
end 

# subcategories_controller.rb
class SubcategoriesController < ApplicationController
    def self.getAll
        return Category.all
    end
    def index
        @data = SubcategoriesController.getAll
        # some logic here
        render "list"
    end
end 

# all_controller.rb
class AllController < ApplicationController
    def index
        @categoriesData = CategoriesController.getAll
        @subcategoriesData = SubcategoriesController.getAll
        render 'all'
    end
end 

# list.html.erb
<%= @data %>

# all.html.erb
<%= @categoriesData %>
<%= @subcategoriesData %>

But I have to rewrite a part of logic that is already there ...

Answer 1

You need to explicitly build the output that you need in the all controller action, rather than trying to join the outputs of other actions.

Two approaches:

1. Retrieve the items you want with two database calls, join them together into one big set of list items, then render the list as in the other actions.

   class AllController < ApplicationController
       def index
           categories = Categories.all
           sub_categories = Subcategories.all
           @all = categories + sub_categories
       end
    end
   

2. Retrieve both sets of data, make the list.html page call a partial called _sub_list.html or something, then have a new template for the all page called all.html, which renders the new partial twice, once for each set of data.

   class AllController < ApplicationController
       def index
           @categories = Categories.all
           @sub_categories = Subcategories.all
       end
    end
   

To reuse logic across controllers. use a concern:

module SharedLogic
  extend ActiveSupport::Concern

  def useful_function
    # some code...
  end
end

class SubcategoriesController < ApplicationController
  include SharedLogic

  def index
    @data = SubcategoriesController.getAll
    # some logic here
    useful_function

    render "list"
  end
end