gistfile1.rb

# Change login from script/console
# Grab the session_id from your server log

module ConsoleHelpers
  def set_session(session_id)
    Thread.current[:session_id] = session_id
  end

  def login(user)
    session_id = Thread.current[:session_id]
    raise "Must set current session: set_session(session_id)" unless session_id

    session_class = Class.new(ActiveRecord::Base) do
      set_table_name "sessions"
      
      attr_accessor :hash_data
      def hash_data
        @hash_data ||= Marshal.load(Base64.decode64(data))
      end

      def save_data!
        self.data = Base64.encode64(Marshal.dump(hash_data))
        self.save!
      end
    end

    user = User.find_by_user_name(user) unless user.is_a?(User)

    current_session = session_class.find_by_session_id(session_id)
    current_session.hash_data[:user_id] = user.id
    current_session.save_data!
  end
end

# Usage
>> extend ConsoleHelpers
=> #<Object:0x3799c @controller=#<ApplicationController:0x4825984>
>> set_session('2a19ba7bdf80a275d6215b218ddfe486')
=> "2a19ba7bdf80a275d6215b218ddfe486"
>> login('username')
=> true