Question

I’m adding unobtrusive ajax to my site, so I need to set the layout depending on the request type :

# app/controllers/application_controller.rb
layout Proc.new { |controller| controller.request.xhr? ? 'ajax' : 'application' }

# app/views/layout/ajax.html.erb
<%= render :partial => "shared/flash", :object => flash %>
<%= yield %>

But I also want to use nested layout and have my javascript deal with where to insert ajax retrieved content. According to the rails api layout nil force default layout behavior with inheritance, so I tried this :

layout Proc.new { |controller| controller.request.xhr? ? 'ajax' : nil }

Which doesn’t work, I get no layout at all. The only piece of information I found is an old chat log saying that this, indeed, doesn’t work due to the way Rails handle layout.

Is there a way to achieve this ?

Since a proc returning nil doesn’t work, is their a way to set the layout on a condition beeing met (request.xhr? here). Something like layout_if.

Or should I just add

layout Proc.new { |controller| controller.request.xhr? ? 'ajax' : 'controller_name' }

to every controllers with a different layout ?

My ajax request actually return html, should I cheat a little and return those html elements in .xml files and use respond_to to set the layout ?
(This may be great, for another reason, having differents urls to access with and without layout content could allow for page cache, but there are other way to achieve this.)

Or maybe there is a way better solution.

Answer 1

Rails can do this automatically. For example you create 2 layouts(application.html.erb and application.js.erb). When request is xhr? it will use js(application.js.erb) layout, if standard request comes to the server rails will render application.html.erb.