Module ActionController::HttpAuthentication::Basic

Makes it dead easy to do HTTP Basic and Digest authentication.

Simple Basic example

 class PostsController < ApplicationController
   http_basic_authenticate_with :name => "dhh", :password => "secret", :except => :index

   def index
     render :text => "Everyone can see me!"
   end

   def edit
     render :text => "I'm only accessible if you know the password"
   end
end

Advanced Basic example

Here is a more advanced Basic example where only Atom feeds and the XML API is protected by HTTP authentication, the regular HTML interface is protected by a session approach:

class ApplicationController < ActionController::Base
  before_filter :set_account, :authenticate

  protected
    def set_account
      @account = Account.find_by_url_name(request.subdomains.first)
    end

    def authenticate
      case request.format
      when Mime::XML, Mime::ATOM
        if user = authenticate_with_http_basic { |u, p| @account.users.authenticate(u, p) }
          @current_user = user
        else
          request_http_basic_authentication
        end
      else
        if session_authenticated?
          @current_user = @account.users.find(session[:authenticated][:user_id])
        else
          redirect_to(login_url) and return false
        end
      end
    end
end

In your integration tests, you can do something like this:

def test_access_granted_from_xml
  get(
    "/notes/1.xml", nil,
    'HTTP_AUTHORIZATION' => ActionController::HttpAuthentication::Basic.encode_credentials(users(:dhh).name, users(:dhh).password)
  )

  assert_equal 200, status
end

Simple Digest example

require 'digest/md5'
class PostsController < ApplicationController
  REALM = "SuperSecret"
  USERS = {"dhh" => "secret", #plain text password
           "dap" => Digest::MD5.hexdigest(["dap",REALM,"secret"].join(":"))}  #ha1 digest password

  before_filter :authenticate, :except => [:index]

  def index
    render :text => "Everyone can see me!"
  end

  def edit
    render :text => "I'm only accessible if you know the password"
  end

  private
    def authenticate
      authenticate_or_request_with_http_digest(REALM) do |username|
        USERS[username]
      end
    end
end

Notes

The authenticate_or_request_with_http_digest block must return the user’s password or the ha1 digest hash so the framework can appropriately hash to check the user’s credentials. Returning nil will cause authentication to fail.

Storing the ha1 hash: MD5(username:realm:password), is better than storing a plain password. If the password file or database is compromised, the attacker would be able to use the ha1 hash to authenticate as the user at this realm, but would not have the user’s password to try using at other sites.

In rare instances, web servers or front proxies strip authorization headers before they reach your application. You can debug this situation by logging all environment variables, and check for HTTP_AUTHORIZATION, amongst others.