如何在 rails 中创建单例全局对象? [英] How do I create a singleton global object in rails?

问题描述

我有一个对象，我想创建一次并在我的模型之一中访问它.我把他放在哪里?恐怕如果我把他放在模型类文件中，每次我创建该模型的新实例时，他都会被创建.我只希望这个对象在启动时创建一次.这是对象:

I have an object that I want created once and accessible in one of my models. Where do I put him? I'm afraid if I put him in the model class file he'll get created every time I make a new instance of that model. I only want this object created once at start up. Here's the object:

require 'pubnub'    
publish_key   = 'fdasfs'
subscribe_key = 'sdfsdsf'
secret_key    = 'fsdfsd'
ssl_on        = false

pubnub_obj = Pubnub.new(publish_key,
                    subscribe_key,
                    secret_key,
                    ssl_on)

我在模型中是这样使用他的:

I use him like this in the model:

class Message < ActiveRecord::Base

  def self.send_new_message_client(message)
    message = { 'some_data' => message }
    info = pubnub_obj.publish({
                            'channel' => 'testing',
                            'message' => message
                          })
    puts(info)
  end

end

推荐答案

在 Rails 中，每个请求都会重新创建对象.如果这是某种服务，它应该是请求范围内的单例.

In Rails, objects are recreated on each request. If this is some kind of service, it should be a singleton in the scope of a request.

应使用 ruby​​ 单例 mixin 创建单例对象:

Singleton objects should be created with the ruby singleton mixin:

require 'singleton'

class Pubnub
  include Singleton

  def initialize(publish_key, subscribe_key, secret_key, ssl_on)
    # ...
  end

  def publish
    # ...
  end
end

然后你可以用instance方法调用它:

Then you can call it with the instance method:

Pubnub.instance.publish

这样你就可以确保这个对象实际上是一个单例(只存在一个实例).

This way you make sure that this object will actually be a singleton (only one instance will exist).

您可以将它安全地放在 models 目录中，尽管我通常更喜欢 lib 目录，或者可能会为服务创建一个新目录.视情况而定.

You can place it safely in the models directory, though I often prefer the lib directory or maybe create a new directory for services. It depends on the situation.

希望有帮助！

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