Authlogic with Mongoid (in spirit of http://pastie.org/503478)

authenticable.rb

module Authenticable
  def self.included(model)
    model.class_eval do
      extend ClassMethods
      include InstanceMethods

      field :username
      field :email
      field :crypted_password
      field :password_salt
      field :persistence_token
      field :login_count, :type => Integer, :default => 0
      field :last_request_at, :type => DateTime
      field :last_login_at, :type => DateTime
      field :current_login_at, :type => DateTime
      field :last_login_ip
      field :current_login_ip

      index :username
      index :email
      index :persistence_token
      index :last_login_at

      include Authlogic::ActsAsAuthentic::Base
      include Authlogic::ActsAsAuthentic::Email
      include Authlogic::ActsAsAuthentic::LoggedInStatus
      include Authlogic::ActsAsAuthentic::Login
      include Authlogic::ActsAsAuthentic::MagicColumns
      include Authlogic::ActsAsAuthentic::Password
      include Authlogic::ActsAsAuthentic::PerishableToken
      include Authlogic::ActsAsAuthentic::PersistenceToken
      include Authlogic::ActsAsAuthentic::RestfulAuthentication
      include Authlogic::ActsAsAuthentic::SessionMaintenance
      include Authlogic::ActsAsAuthentic::SingleAccessToken
      include Authlogic::ActsAsAuthentic::ValidationsScope
    end
  end

  module ClassMethods
    def <(klass)
      return true if klass == ::ActiveRecord::Base
      super(klass)
    end

    def column_names
      fields.map &:first
    end

    def quoted_table_name
      'users'
    end

    def primary_key
      # FIXME: Is this check good enough?
      if caller.first.to_s =~ /(persist|session)/
        :_id
      else
        @@primary_key
      end
    end

    def default_timezone
      :utc
    end

    def find_by__id(*args)
      find *args
    end

    # Change this to your preferred login field
    def find_by_username(username)
      where(:username => username).first
    end

    def with_scope(query)
      query = where(query) if query.is_a?(Hash)
      yield query
    end
  end

  module InstanceMethods
    def readonly?
      false
    end
  end
end

user.rb

class User
  include Mongoid::Document
  include Mongoid::Timestamps

  include Authenticable

  acts_as_authentic do |config|
    # Change this to your preferred login field
    config.login_field = 'username'
    config.merge_validates_uniqueness_of_login_field_options :scope => '_id', :case_sensitive => true
  end
end

user_session.rb

class UserSession < Authlogic::Session::Base
  def to_key
    new_record? ? nil : [self.send(self.class.primary_key)]
  end
end

Understand where a problem :(

Started POST "/sessions" for 127.0.0.1 at 2011-11-07 16:09:18 +0300
Processing by SessionsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"bB2XWOa8vsAW0Zd2DK0GeTAaOgpU5cbUK7JPnFsaH2s=", "session"=>{"username"=>"jpascal", "password"=>"[FILTERED]"}, "commit"=>"Login"}
MONGODB grabs['system.namespaces'].find({})
MONGODB grabs['users'].find({:username=>"jpascal"}).limit(-1).sort([[:_id, :asc]])
Completed 500 Internal Server Error in 185ms

TypeError (nil is not a symbol):
app/controllers/sessions_controller.rb:10:in `create'

Rendered /usr/local/rvm/gems/ruby-1.9.2-p290@hotelgrab/gems/actionpack-3.1.1/lib/action_dispatch/middleware/templates/rescues/_trace.erb (2.5ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290@hotelgrab/gems/actionpack-3.1.1/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (2.1ms)
Rendered /usr/local/rvm/gems/ruby-1.9.2-p290@hotelgrab/gems/actionpack-3.1.1/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (8.5ms)

class SessionsController < ApplicationController
...
def create
@user_session = UserSession.new(params[:session])
if @user_session.save
redirect_to root_url
else
render :action => 'new'
end
end
...
end

index({:username => 1}, {:unique => true})
index({:email => 1}, {:unique => true})
index({:persistence_token => 1}, {:unique => true})

It's new syntax for creating indexes