Rails - 如何在初始化器中设置全局实例变量？

Question

我正在使用预测宝石.我将推荐人初始化为initializers/predictor.rb:

require 'course_recommender'    

recommender = CourseRecommender.new

# Add records to the recommender.
recommender.add_to_matrix!(:topics, "topic-1", "course-1")
recommender.add_to_matrix!(:topics, "topic-2", "course-1")
recommender.add_to_matrix!(:topics, "topic-1", "course-2")

然后我想在CourseController中使用推荐器,如下所示:

class CourseController < ApplicationController
  def show
    # I would like to access the recommender here.
    similiar_courses = recommender.similarities_for("course-1")
  end
end

我怎样才能设置recommender为应用程序控制器变量,以便在控制器中访问它？

Answer 1

在您的作品中,initilizers/predictor.rb您应将推荐人定义为:

recommender = CourseRecommender.new

但是:

:: Recommender = CourseRecommender.new

这样,您可以在应用程序的整个范围内定义常量,而不是定义局部变量.在初始化程序和控制器中,您可以访问它Recommender.

Answer 2

我解决了这个问题。但我没有设置全局实例，而是使用单例模式。

这是代码：

# lib/course_recommender.rb
require 'singleton'
class CourseRecommender
  include Predictor::Base
  include Singleton
  # ...
end

# initializers/predictor.rb
@recommender = CourseRecommender.instance

# Add records to the recommender.
@recommender.add_to_matrix!(:topics, "topic-1", "course-1")
@recommender.add_to_matrix!(:topics, "topic-2", "course-1")
@recommender.add_to_matrix!(:topics, "topic-1", "course-2")

# controllers/course_controller.rb
require 'course_recommender'
class CourseController < ApplicationController
  def show
    similiar_courses = CourseRecommender.instance.similarities_for("course-1")
  end
end