What is a very simple authentication scheme for Sinatra/Rack

Question

I am busy porting a very small web app from ASP.NET MVC 2 to Ruby/Sinatra.

In the MVC app, FormsAuthentication.SetAuthCookie was being used to set a persistent cookie when the users login was validated correctly against the database.

I was wondering what the equivalent of Forms Authentication would be in Sinatra? All the authentication frameworks seem very bulky and not really what I'm looking for.

Answer 1

Here is a very simple authentication scheme for Sinatra.

I'll explain how it works below.

class App < Sinatra::Base
  set :sessions => true

  register do
    def auth (type)
      condition do
        redirect "/login" unless send("is_#{type}?")
      end
    end
  end

  helpers do
    def is_user?
      @user != nil
    end
  end

  before do
    @user = User.get(session[:user_id])
  end

  get "/" do
    "Hello, anonymous."
  end

  get "/protected", :auth => :user do
    "Hello, #{@user.name}."
  end

  post "/login" do
    session[:user_id] = User.authenticate(params).id
  end

  get "/logout" do
    session[:user_id] = nil
  end
end

For any route you want to protect, add the :auth => :user condition to it, as in the /protected example above. That will call the auth method, which adds a condition to the route via condition .

The condition calls the is_user? method, which has been defined as a helper. The method should return true or false depending on whether the session contains a valid account id. (Calling helpers dynamically like this makes it simple to add other types of users with different privileges.)

Finally, the before handler sets up a @user instance variable for every request for things like displaying the user's name at the top of each page. You can also use the is_user? helper in your views to determine if the user is logged in.

Answer 2

Todd's answer does not work for me, and I found an even simpler solution for one-off dead simple authentication in Sinatra's FAQ :

require 'rubygems'
require 'sinatra'

use Rack::Auth::Basic, "Restricted Area" do |username, password|
    [username, password] == ['admin', 'admin']  
end

get '/' do
    "You're welcome"
end

I thought I would share it just in case anyone wandered this question and needed a non-persistent solution.

Answer 3

I' have found this tutorial and repository with a full example, its working fine for me

https://sklise.com/2013/03/08/sinatra-warden-auth/

https://github.com/sklise/sinatra-warden-example

Answer 4

I used the accepted answer for an app that just had 2 passwords, one for users and one for admins. I just made a login form that takes a password(or pin) and compared that to one that I had set in sinatra's settings (one for admin, one for user). Then I set the session[:current_user] to either admin or user according to which password the user entered and authorized accordingly. I didn't even need a user model. I did have to do something like this:

use Rack::Session::Cookie, :key => 'rack.session',
                       :domain => 'foo.com',
                       :path => '/',
                       :expire_after => 2592000, # In seconds
                       :secret => 'change_me'

As mentioned in the sinatra documentation to get the session to persist in chrome. With that added to my main file, they persist as expected.