Makes it dead easy to do HTTP Token authentication.

Simple Token example:

class PostsController < ApplicationController
  TOKEN = "secret"

  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_token do |token, options|
        token == TOKEN
      end
    end
end

Here is a more advanced Token example where only Atom feeds and the XML API is protected by HTTP token 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_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
  get(
    "/notes/1.xml", nil,
    :authorization => ActionController::HttpAuthentication::Token.encode_credentials(users(:dhh).token)
  )

  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
Methods
A
E
T
Instance Public methods
authenticate(controller, &login_procedure)

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

controller - ActionController::Base instance for the current request. login_procedure - Proc to call if a token is present. The Proc should

take 2 arguments:
  authenticate(controller) { |token, options| ... }

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

Source: show | on GitHub 

# File actionpack/lib/action_controller/metal/http_authentication.rb, line 412
def authenticate(controller, &login_procedure)
  token, options = token_and_options(controller.request)
  unless token.blank?
    login_procedure.call(token, options)
  end
end
authentication_request(controller, realm)

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

controller - ActionController::Base instance for the outgoing response. realm - String realm to use in the header.

Returns nothing.

Source: show | on GitHub 

# File actionpack/lib/action_controller/metal/http_authentication.rb, line 460
def authentication_request(controller, realm)
  controller.headers["WWW-Authenticate"] = %Q(Token realm="#{realm.gsub(/"/, "")}")
  controller.__send__ :render, :text => "HTTP Token: Access denied.\n", :status => :unauthorized
end
encode_credentials(token, options = {})

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

token - String token. options - optional Hash of the options.

Returns String.

Source: show | on GitHub 

# File actionpack/lib/action_controller/metal/http_authentication.rb, line 447
def encode_credentials(token, options = {})
  values = ["token=#{token.to_s.inspect}"] + options.map do |key, value|
    "#{key}=#{value.to_s.inspect}"
  end
  "Token #{values * ", "}"
end
token_and_options(request)

Parses the token and options out of the token authorization header. If the header looks like this:

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

Then the returned token is “abc”, and the options is {:nonce => “def”}

request - ActionDispatch::Request instance with the current headers.

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

Source: show | on GitHub 

# File actionpack/lib/action_controller/metal/http_authentication.rb, line 428
def token_and_options(request)
  if request.authorization.to_s[%r^Token (.*)/]
    values = Hash[$1.split(',').map do |value|
      value.strip!                      # remove any spaces between commas and values
      key, value = value.split(%r\=\"?/) # split key=value pairs
      value.chomp!('"')                 # chomp trailing " in value
      value.gsub!(%r\\\"/, '"')          # unescape remaining quotes
      [key, value]
    end]
    [values.delete("token"), values.with_indifferent_access]
  end
end