Never render a layout in response to xhrs

Question

Most of the time I don't want to render a layout when the request comes from AJAX. To this end I've been writing render :layout => !request.xhr? frequently in my controller actions.

How can I make this the default? I.e., I'd like to be able to write

def new
  Post.find(params[:id])
end

and have the functionality be

def show
  Post.find(params[:id])
  render :layout => !request.xhr?
end

(I'm fine manually specifying a layout in the rare cases in which I want to use one.)

Answer 1

How about this?

class UsersController < ApplicationController
  layout proc {|controller| controller.request.xhr? ? false : "application" }
end

Answer 2

In order to make it the default to never render a layout for any XHR request, you can do this:

class ApplicationController < ActionController::Base
  layout proc { false if request.xhr? }
end

When the request is an XHR request, it renders the requested view without a layout. Otherwise, it uses the default layout behaviour, which looks up the layout by inheritance.

This is different than saying controller.request.xhr? ? false : 'application', since that will always render the application layout for a non-XHR request, which effectively disables the lookup by inheritance.

Also see the ActionView documentation for the nil argument and layout inheritance.