Rails: respond_to JSON and HTML

I have a controller "UserController" that should respond to normal and ajax requests to http://localhost:3000/user/3.

When it is a normal request, I want to render my view. When it is an AJAX request, I want to return JSON.

The correct approach seems to be a respond_to do |format| block. Writing the JSON is easy, but how can I get it to respond to the HTML and simply render the view as usual?

  def show
    @user = User.find(params[:id])
    respond_to do |format|
      format.html {
        render :show ????this seems unnecessary. Can it be eliminated??? 
      }
      format.json { 
        render json: @user
      }
    end
  end

As per my knowledge its not necessary to "render show" in format.html it will automatically look for a respective action view for ex : show.html.erb for html request and show,js,erb for JS request.

so this will work

respond_to do |format|

  format.html # show.html.erb
  format.json { render json: @user }

 end

also, you can check the request is ajax or not by checking request.xhr? it returns true if request is a ajax one.

Yes, you can change it to

respond_to do |format|
  format.html
  format.json { render json: @user }
end

The best way to do this is just like Amitkumar Jha said, but if you need a simple and quick way to render your objects, you can also use this "shortcut":

def index
  @users = User.all
  respond_to :html, :json, :xml
end

Or make respond_to work for all the actions in the controller using respond_with :

class UserController < ApplicationController
  respond_to :html, :json, :xml

  def index
    @users = User.all
    respond_with(@users)
  end
end

Starting from Rails 4.2 version you will need to use gem responder to be able to use respond_with.

If you need more control and want to be able to have a few actions that act differently, always use a full respond_to block. You can read more here.