在Module Class方法中，是否可以获得那个混合模块的Class？

I have a Module A, and there are several Class need to Mixin it, there is a method should be wrote as Class Method of that Module, but this method need to get data from the Tables which match these Classes. It that realizable?

我有一个模块A，并且有几个类需要Mixin它，有一个方法应该写为该模块的类方法，但是这个方法需要从与这些类匹配的表中获取数据。那可以实现吗？

module Authenticate
  def password=(password)
    if password.present?
      generate_salt
      self.hashed_password = Authenticate.encrypt_password(password, salt)
    end
  end

  class << self
    def encrypt_password(password,salt)
      Digest::SHA2.hexdigest(password + salt)
    end
  end

  private
  def generate_salt
    self.salt = self.object_id.to_s + rand.to_s
  end

end


require 'authenticate_module'
class Administrator < ActiveRecord::Base
  validates :password, :confirmation => true
  attr_accessor :password_confirmation
  attr_reader :password
  include Authenticate
end

This is that method:

这是方法：

def authenticate(name,password)
  if user = ???.find_by_name(name)
    if user.hashed_password == Authenticate.encrypt_password(password,user.salt)
      user
    end
  end
end

1 个解决方案

#1

Use ActiveSupport::Concern to add class methods to every class that includes your module, then calling self in that method will return the class name.

使用ActiveSupport :: Concern将类方法添加到包含模块的每个类，然后在该方法中调用self将返回类名。

It will be something like:

它将是这样的：

module Authenticate
  extend ActiveSupport::Concern

  module ClassMethods
    def authenticate(name, password)
      self.class # returns the name of the class that includes this module 
    end
  end
end


class User
  include Authenticate
end


# Now You can call
User.authenticate(name, password)

What ActiveSupport::Concern does is that whenever a class includes the module, it extends that class with the ClassMethods which here is equivalent to doing

ActiveSupport :: Concern所做的是，每当一个类包含该模块时，它都会使用ClassMethods扩展该类，这里等同于

class User
  include Authenticate
  extend Authenticate::ClassMethods
end

#1