How to respond to HTML requests made via AJAX in Rails

Question

I\'m trying to write a Rails controller method that will respond to get requests made both \"normally\" (e.g. following a link) and via ajax.

Normal Case: The controller

Answer 1

In your controller method, simply do this:

   respond_to do |format|
      format.js if request.xhr?
      format.html { redirect_to :action => "index"}
    end

Answer 2

In your controller dynamically select whether to use a layout based on request.xhr?.

For example:

class SomeController < ApplicationController
  layout :get_layout

  protected

  def get_layout
    request.xhr? ? nil : 'normal_layout'
  end
end

Answer 3

Another way of doing this would be to register new format and specify it explicitly in urls.

Put this in config/initializers/mime_types.rb:

Mime::Type.register_alias 'text/html', :xhtml

Save your template in some_controller/some_action.xhml.haml.

And add format to url: http://mydomain.com/some_controller/some_action.xhtml, or, better, use

url_for(:controller => :some_controller, :action => :some_action, :format => :xhtml)

or, even better, path helpers (if you are restful enough):

some_controller_some_action_imaginary_path(:format => :xhtml)

Mind, that no explicit respond_to dispatching is required for this to work.

This technique might be an overkill if all you want is toggle layout for the same template, but if normal and ajax versions are different, then it is certainly a way to go.

EDIT:
The just released jQuery 1.5.1 brings the option to specify mime type in $.ajax():

mimeType: A mime type to override the XHR mime type.

This may be an alternative to explicit format in urls, though I haven't tried it yet.

Answer 4

If you're using a new version of rails you can just append .js onto the path and it will infer that the request is a JavaScript call