Custom authenticator to be used by rubycas-server

custom_authenticator.rb

# encoding: UTF-8
require 'casserver/authenticators/sql'

require 'devise/encryptors/base'
require 'devise/encryptors/sha1'

class CustomAuthenticator < CASServer::Authenticators::SQL
  # snip from devise lib
  def secure_compare(a, b)
    return false unless a.present? && b.present?
    return false unless a.bytesize == b.bytesize
    l = a.unpack "C#{a.bytesize}"

    res = 0
    b.each_byte { |byte| res |= byte ^ l.shift }
    res == 0
  end

  # copied from devise.rb initializer
  DEVISE_STRETCHES = 7
  DEVISE_PEPPER = 'my-devise-pepper'

  def password_digest(password, password_salt)
    Devise::Encryptors::Sha1.digest(password, DEVISE_STRETCHES, password_salt, DEVISE_PEPPER)
  end

  def valid_for_authentication?(user, incoming_password)
    secure_compare(password_digest(incoming_password,user.password_salt), user.encrypted_password)
  end

  def validate(credentials)
    read_standard_credentials(credentials)
    raise_if_not_configured

    user_model = self.class.user_model

    username_column = @options[:username_column] || "username"

    $LOG.debug "#{self.class}: [#{user_model}] " + "Connection pool size: #{user_model.connection_pool.instance_variable_get(:@checked_out).length}/#{user_model.connection_pool.instance_variable_get(:@connections).length}"
    results = user_model.find(:all, :conditions => ["#{username_column} = ?", @username])
    user_model.connection_pool.checkin(user_model.connection)

    if results.size > 0
      $LOG.warn("Multiple matches found for user '#{@username}'") if results.size > 1
      user = results.first
      unless @options[:extra_attributes].blank?
        if results.size > 1
          $LOG.warn("#{self.class}: Unable to extract extra_attributes because multiple matches were found for #{@username.inspect}")
        else
          extract_extra(user)
              log_extra
        end
      end
      return valid_for_authentication? user, @password
    else
      return false
    end
  end
end