Ruby gem 方法只能在控制器中使用？如果是这样，如何使其在其他文件中可用？

Question

我的印象是 gem 的方法可以在 Rails 应用程序的任何地方访问，一旦它与捆绑器一起安装。但事实并非如此吗？我很困惑，因为 controller 中可访问的方法在移出文件时无法识别。有什么方法可以要求 gem 到运行下面的代码 command 文件而不是 controller?

我正在使用名为 sorcery to implement an OAuth login system. There are some methods 的身份验证 gem，类似于 gem 提供的 login_from(provider)，可以从我的控制器访问它。

# app/controllers/oauths_controller.rb
class OauthsController < ApplicationController
  skip_before_action :require_login

  def callback
    provider = params[:provider]
    if @user = login_from(provider)
    # method continues
  end

但是，我们正在尝试在我们的应用程序中采用命令查询分离方法，因此我尝试将包含 login_from(provider) 方法的这个进程移动到另一个名为 app/commands/authentication/login_command.rb 的文件中。这导致无法识别该方法：

NoMethodError (undefined method 'login_from' for #<Authentication::LoginCommand:>)

提前致谢。

Answer 1

I was under the impression that a gem's methods can be accessed anywhere in the Rails app once it's been installed with bundler.

这是一种错误的印象。

如您所见，Sorcery::Engine 导致 ActionController::Base 包含 Sorcery::Controller 中定义的方法，此处：

require 'sorcery'
require 'rails'

module Sorcery
  # The Sorcery engine takes care of extending ActiveRecord (if used) and ActionController,
  # With the plugin logic.
  class Engine < Rails::Engine
    config.sorcery = ::Sorcery::Controller::Config

    initializer 'extend Controller with sorcery' do
      # TODO: Should this include a modified version of the helper methods?
      if defined?(ActionController::API)
        ActionController::API.send(:include, Sorcery::Controller)
      end

      if defined?(ActionController::Base)
        ActionController::Base.send(:include, Sorcery::Controller)
        ActionController::Base.helper_method :current_user
        ActionController::Base.helper_method :logged_in?
      end
    end
  end
end

Sorcer::Controller依次包含一系列子模块：

module Sorcery
  module Controller
    def self.included(klass)
      klass.class_eval do
        include InstanceMethods
        Config.submodules.each do |mod|
          # FIXME: Is there a cleaner way to handle missing submodules?
          # rubocop:disable Lint/HandleExceptions
          begin
            include Submodules.const_get(mod.to_s.split('_').map(&:capitalize).join)
          rescue NameError
            # don't stop on a missing submodule.
          end
          # rubocop:enable Lint/HandleExceptions
        end
      end
      Config.update!
      Config.configure!
    end

    ...
  end
end

这些子模块之一是 Sourcery::Controller::Submodules::External，当包含时，还包含 Sourcery::Controller::Submodules::External::InstanceMethods，此处：

module Sorcery
  module Controller
    module Submodules
      # This submodule helps you login users from external auth providers such as Twitter.
      # This is the controller part which handles the http requests and tokens passed between the app and the @provider.
      module External
        def self.included(base)
          base.send(:include, InstanceMethods)
          ...
        end
      end
    end
  end
end

并且，InstanceMethods 包含方法 login_from，此处：

module Sorcery
  module Controller
    module Submodules
      # This submodule helps you login users from external auth providers such as Twitter.
      # This is the controller part which handles the http requests and tokens passed between the app and the @provider.
      module External
        def self.included(base)
          base.send(:include, InstanceMethods)

        module InstanceMethods
          protected

          ...

          # tries to login the user from provider's callback
          def login_from(provider_name, should_remember = false)
            sorcery_fetch_user_hash provider_name

            return unless (user = user_class.load_from_provider(provider_name, @user_hash[:uid].to_s))

            # we found the user.
            # clear the session
            return_to_url = session[:return_to_url]
            reset_sorcery_session
            session[:return_to_url] = return_to_url

            # sign in the user
            auto_login(user, should_remember)
            after_login!(user)

            # return the user
            user
          end

          ...
        end
      end
    end
  end
end

Soooo，说 login_from 被定义为继承自 ActionController::Base 的类上的受保护实例方法并没有被定义为类不从 ActionController::Base 继承，这就是为什么你得到 NoMethodError。

Is there some way I could require the gem to run the code below in the command file instead of the controller?

也许吧。也许不吧。如您所见，login_from 正在使用其他 sorcery 方法和继承自 ActionController::Base 的方法。因此，您需要确保所有这些方法都在 Authentication::LoginCommand 中可用，以便 login_from 正常运行。

Ruby gem 方法只能在控制器中使用？如果是这样，如何使其在其他文件中可用？

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