How do I use sub-controllers in Ruby on Rails?

I am learning RoR, and I have a general design issue that I'm trying to work around. I want to get some input on the answer to make sure I follow some kind of best practice.

I have a page that's made up of 3 subsections, let's call them A, B, and C. Certain actions cause each of these to refresh via AJAX, so I want to have them each have a controller action that allows any of them to render individually, without the page chrome.

The way I've structured this right now is with a controller that has 4 actions: index, A, B, C

Each of A, B, and C renders its view with layout=>false so I can render just that piece via AJAX when needed. Then, you have index, which renders some extra stuff along with the view of A, B, and C.

Esentially what I want here are 3 subcontrollers, and a master controller that invokes the subcontrollers as needed. Or I think that is what I want. What I think I don't want is partial views, because there is some setup I do in the controller for each of A,B,C and I would then have to duplicate the setup code in both the controller for index and the controller for A,B,C.

The code I have in mind is something like this:

my_controller.rb:

class MyController < ApplicationController
    def index
         @aOutput = A
         @bOutput = B
         @cOutput = C
         render //can use @aOutput, @bOutput, @cOutput in the view
    end

    def A
        render :layout => false    
    end

    def B
        render :layout => false
    end

    def C
        render :layout => false
    end
end

This would enable me to now access MyController#index when I want the full page, and MyController#A, etc when I want to re-render the contents of each subsection.

The problem here is if the code is structured like this, you will run into DoubleRender errors when accessing MyController#index. What is the correct way to approach this kind of thing? Feel free to blow up any assumptions I made here, with the only requirement being a page that has three sections that can update individually as needed without r开发者_运维百科eloading the whole page.

I am not sure if I understand the problem clearly but I think here is what I think your problem is.

• You want to be able to render only a view without invoking controller action entire.

  This can be done by using render :action => :action_name

• You want to render some text only for ajax calls

  Use respond_to block in order to achieve this. For example.

  def whatever_action
  
    .... # Your action voodoo here
  
    respond_to do |format|
      format.html { ... } # If it a normal HTTP request
      format.js {...} # If it's an ajax or JSON request
    end
  end       
  

The design that you are proposing has basic flaws like non-adherence to some of the SOLID design principles. I strongly recommend reading a good book on basics of rails.