HTTP basic authentication

HTTP basic authentication can be done in old rails versions through this plugin.

class ApplicationController < ActionController::Base
  htpasswd :user => 'username', :pass => 'secret'
end

Edge rails has its own HttpAuthentication::Basic module:

class ApplicationController < ActionController::Base
  USERNAME, PASSWORD = 'username', 'secret'
  before_filter :basic_http_authentication
  private
    def basic_http_authentication
      authenticate_or_request_with_http_basic do |username, password|
        username == USERNAME and password == PASSWORD
      end
    end
end

I haven't tried the edge rails version though.