HTTP Token authentication

Simple Token example

class PostsController < ApplicationController
  TOKEN = "secret"

  before_action :authenticate, except: [ :index ]

  def index
    render plain: "Everyone can see me!"
  end

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

  private
    def authenticate
      authenticate_or_request_with_http_token do |token, options|
        # Compare the tokens in a time-constant manner, to mitigate
        # timing attacks.
        ActiveSupport::SecurityUtils.secure_compare(token, TOKEN)
      end
    end
end

Here is a more advanced Token example where only Atom feeds and the XML API are protected by HTTP token authentication. The regular HTML interface is protected by a session approach:

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

  private
    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_token { |t, o| @account.users.authenticate(t, o) }
          @current_user = user
        else
          request_http_token_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
  authorization = ActionController::HttpAuthentication::Token.encode_credentials(users(:dhh).token)

  get "/notes/1.xml", headers: { 'HTTP_AUTHORIZATION' => authorization }

  assert_equal 200, status
end

On shared hosts, Apache sometimes doesn’t pass authentication headers to FCGI instances. If your environment matches this description and you cannot authenticate, try this rule in your Apache setup:

RewriteRule ^(.*)$ dispatch.fcgi [E=X-HTTP_AUTHORIZATION:%{HTTP:Authorization},QSA,L]

Namespace

Module

Methods

Constants

AUTHN_PAIR_DELIMITERS = /(?:,|;|\t)/
TOKEN_KEY = "token="
TOKEN_REGEX = /^(Token|Bearer)\s+/

Instance Public methods

authenticate(controller, &login_procedure)

If token Authorization header is present, call the login procedure with the present token and options.

Returns the return value of login_procedure if a token is found. Returns nil if no token is found.

Parameters

  • controller - ActionController::Base instance for the current request.

  • login_procedure - Proc to call if a token is present. The Proc should take two arguments:

    authenticate(controller) { |token, options| ... }
πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 472
      def authenticate(controller, &login_procedure)
        token, options = token_and_options(controller.request)
        unless token.blank?
          login_procedure.call(token, options)
        end
      end
πŸ”Ž See on GitHub

authentication_request(controller, realm, message = nil)

Sets a WWW-Authenticate header to let the client know a token is desired.

Returns nothing.

Parameters

πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 555
      def authentication_request(controller, realm, message = nil)
        message ||= "HTTP Token: Access denied.\n"
        controller.headers["WWW-Authenticate"] = %(Token realm="#{realm.tr('"', "")}")
        controller.__send__ :render, plain: message, status: :unauthorized
      end
πŸ”Ž See on GitHub

encode_credentials(token, options = {})

Encodes the given token and options into an Authorization header value.

Returns String.

Parameters

  • token - String token.

  • options - Optional Hash of the options.

πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 539
      def encode_credentials(token, options = {})
        values = ["#{TOKEN_KEY}#{token.to_s.inspect}"] + options.map do |key, value|
          "#{key}=#{value.to_s.inspect}"
        end
        "Token #{values * ", "}"
      end
πŸ”Ž See on GitHub

params_array_from(raw_params)

Takes raw_params and turns it into an array of parameters.

πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 507
      def params_array_from(raw_params)
        raw_params.map { |param| param.split %r/=(.+)?/ }
      end
πŸ”Ž See on GitHub

raw_params(auth)

This method takes an authorization body and splits up the key-value pairs by the standardized :, ;, or \t delimiters defined in AUTHN_PAIR_DELIMITERS.

πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 519
      def raw_params(auth)
        _raw_params = auth.sub(TOKEN_REGEX, "").split(AUTHN_PAIR_DELIMITERS).map(&:strip)
        _raw_params.reject!(&:empty?)

        if !_raw_params.first&.start_with?(TOKEN_KEY)
          _raw_params[0] = "#{TOKEN_KEY}#{_raw_params.first}"
        end

        _raw_params
      end
πŸ”Ž See on GitHub

rewrite_param_values(array_params)

This removes the " characters wrapping the value.

πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 512
      def rewrite_param_values(array_params)
        array_params.each { |param| (param[1] || +"").gsub! %r/^"|"$/, "" }
      end
πŸ”Ž See on GitHub

token_and_options(request)

Parses the token and options out of the token Authorization header. The value for the Authorization header is expected to have the prefix "Token" or "Bearer". If the header looks like this:

Authorization: Token token="abc", nonce="def"

Then the returned token is "abc", and the options are {nonce: "def"}.

Returns an Array of [String, Hash] if a token is present. Returns nil if no token is found.

Parameters

πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 494
      def token_and_options(request)
        authorization_request = request.authorization.to_s
        if authorization_request[TOKEN_REGEX]
          params = token_params_from authorization_request
          [params.shift[1], Hash[params].with_indifferent_access]
        end
      end
πŸ”Ž See on GitHub

token_params_from(auth)

πŸ“ Source code 
# File actionpack/lib/action_controller/metal/http_authentication.rb, line 502
      def token_params_from(auth)
        rewrite_param_values params_array_from raw_params auth
      end
πŸ”Ž See on GitHub