Rails:如何扩展gem的ActiveRecord子类？

Question

我在扩展一个在gem中定义的类并且是ActiveRecord :: Base的子类时遇到了问题.

我唯一想扩展这个类的是: has_many :promos

然而,扩展倾向于排除原始类.我得到的错误:

PGError: ERROR:  relation "sites" does not exist
LINE 4:              WHERE a.attrelid = '"sites"'::regclass
                                        ^
:             SELECT a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull
              FROM pg_attribute a LEFT JOIN pg_attrdef d
                ON a.attrelid = d.adrelid AND a.attnum = d.adnum
             WHERE a.attrelid = '"sites"'::regclass
               AND a.attnum > 0 AND NOT a.attisdropped
             ORDER BY a.attnum

检查控制台中的类给出:

Cms::Site(Table doesn't exist)

原始类有这个方法,可能不再被调用:

set_table_name :cms_sites

顺便说一句.我正在尝试从comfortable_mexican_sofa插件扩展Site类.

这是应该扩展类的文件:

# lib/comfortable_media_sofa/comfortable_media_sofa.rb
require 'comfortable_mexican_sofa'

module Cms
  class Site < ActiveRecord::Base
    has_many :promos
  end
end

哪个在这里加载:

require File.expand_path('../boot', __FILE__)

require 'rails/all'

Bundler.require(:default, Rails.env) if defined?(Bundler)

module Mkturbo
  class Application < Rails::Application
    config.autoload_paths += %W(#{config.root}/vendor/gems/comfortable_mexican_sofa-0.0.18)
    config.autoload_paths += %W(#{config.root}/lib/comfortable_media_sofa)
    config.plugins = [ :comfortable_mexican_sofa, :comfortable_media_sofa, :all ]

    # ....
  end
end

并且在comfortable_mexican_sofa初始化程序的顶部是必需的:

# config/initializers/comfortable_mexican_sofa.rb
require 'comfortable_media_sofa'

我怎样才能做到这一点？是需求订单问题还是我以错误的方式扩展？提前谢谢了!

Answer 1

在你的例子中,你完全覆盖了那个类.你只需要把东西注入其中......就像这样:

module MyModule
  def self.included(base)
    base.has_many :things
  end
end
Cms::Site.send(:include, MyModule)

然后,只是为了看看协会是否开始:

ruby-1.9.2-p180 :005 > s = Cms::Site.new
=> #<Cms::Site id: nil, label: nil, hostname: nil> 
ruby-1.9.2-p180 :006 > s.things
NameError: uninitialized constant Cms::Site::Thing

我实际上将该模块直接放入沙发的初始化器中.希望这可以帮助.