Accessing current_user variable from application.js in Rails 3

Question

I wish to access my current_user variable from my application.js (I renamed my application.js to application.js.erb so the server could understand my ruby code), so i got something like:

function hello(){ alert("<%= current_user.name %>"); }

But it fails:

How can i get session variables like the current_user from devise gem working from a script located in /assets/my_script.js.erb, i think it should not be abled because theese variables might not be accesisible from public sites, or what should do about this?

Thanks!

Answer 1

Application.js is not evaluated in the context of any session variables or methods. The simplest way to access username from javascript would be to set a cookie in a before_action on application controller:

class ApplicationController < ActionController::Base
  before_action :set_user

  private

  def set_user
    cookies[:username] = current_user.name || 'guest'
  end
end

Then from any js in app/assets you can access the cookie:

alert(document.cookie);

A more verbose but arguably cleaner method would be to create a route that accesses the current user and returns the username e.g.

routes.rb

get 'current_user' => "users#current_user"

users_controller.rb

def current_user
    render json: {name: current_user.name}
end

application.js

$.get('/current_user', function(result){
  alert(result.name);
});

Answer 2

1. Take a look at this episode in rails casts
2. Try using the gon gem