Ruby on rails Ruby mixin模块的规格有问题

我对mixin模块没有很好的经验。那么，如果我的问题有点天真，请原谅我

我正在创建几个模块，将一个项目与音乐服务（如Spotify）集成，后者拥有REST API。所有这些模块都包括我创建的另一个名为APIClientBuilder的mixin模块，它提供了一个用于创建API端点的小型DSL

lib/integrations/api\u client\u builder.rb

require 'rest-client'

module APIClientBuilder

  attr_accessor :api_client, :endpoint, :url, :param

  def api_client(api_name)
  end

  def fetch_client(api_name)
  end

  def api_endpoint(endpoint_name)
  end

  def fetch_endpoint(api_name,endpoint_name)
  end 

  def method=(meth)
  end   

  def url=(endpoint_url) 
  end

  def param(param_name,param_value)
  end

  def call(api_name,api_endpoint,token,*extra_params)
  end

end

require_relative 'api_client_builder'

module SpotifyIntegration

  include APIClientBuilder

  def base_url
    'https://api.spotify.com/v1'
  end

  def random_state_string
    (0..10).map { (65 + rand(26)).chr }.join
  end

  api_client('spotify') do |apic|

    apic.api_endpoint('request_authorization') do |ep|
      ep.method = :get
      ep.url = "https://accounts.spotify.com/authorize"
      ep.param("client_id",SPOTIFY_KEY)
      ep.param("response_type","code")
      ep.param("redirect_uri","http://localhost:3000")
    end

    apic.api_endpoint('my_playlists') do |ep|
      ep.method = :get
      ep.url = "#{base_url}/me/playlists"
    end

  end

end

require 'integrations/spotify.rb'

class UsersController < ApplicationController

  include SpotifyIntegration

end

require 'rails_helper'

require 'integrations/spotify'

class SpotifyClientTester
  include SpotifyIntegration
end

RSpec.describe SpotifyIntegration do

  context 'Auxiliary methods' do

    it 'Two calls to random_state_string shall generate two different strings' do
      obj = SpotifyClientTester.new
      s1 = obj.random_state_string
      s2 = obj.random_state_string
      expect(s1).not_to eq(s2)
    end

  end

end

lib/integrations/spotify.rb

require 'rest-client'

module APIClientBuilder

  attr_accessor :api_client, :endpoint, :url, :param

  def api_client(api_name)
  end

  def fetch_client(api_name)
  end

  def api_endpoint(endpoint_name)
  end

  def fetch_endpoint(api_name,endpoint_name)
  end 

  def method=(meth)
  end   

  def url=(endpoint_url) 
  end

  def param(param_name,param_value)
  end

  def call(api_name,api_endpoint,token,*extra_params)
  end

end

require_relative 'api_client_builder'

module SpotifyIntegration

  include APIClientBuilder

  def base_url
    'https://api.spotify.com/v1'
  end

  def random_state_string
    (0..10).map { (65 + rand(26)).chr }.join
  end

  api_client('spotify') do |apic|

    apic.api_endpoint('request_authorization') do |ep|
      ep.method = :get
      ep.url = "https://accounts.spotify.com/authorize"
      ep.param("client_id",SPOTIFY_KEY)
      ep.param("response_type","code")
      ep.param("redirect_uri","http://localhost:3000")
    end

    apic.api_endpoint('my_playlists') do |ep|
      ep.method = :get
      ep.url = "#{base_url}/me/playlists"
    end

  end

end

require 'integrations/spotify.rb'

class UsersController < ApplicationController

  include SpotifyIntegration

end

require 'rails_helper'

require 'integrations/spotify'

class SpotifyClientTester
  include SpotifyIntegration
end

RSpec.describe SpotifyIntegration do

  context 'Auxiliary methods' do

    it 'Two calls to random_state_string shall generate two different strings' do
      obj = SpotifyClientTester.new
      s1 = obj.random_state_string
      s2 = obj.random_state_string
      expect(s1).not_to eq(s2)
    end

  end

end

我的想法是在我的控制器里有这样的东西：

app/controllers/api/v1/users\u controller.rb

require 'rest-client'

module APIClientBuilder

  attr_accessor :api_client, :endpoint, :url, :param

  def api_client(api_name)
  end

  def fetch_client(api_name)
  end

  def api_endpoint(endpoint_name)
  end

  def fetch_endpoint(api_name,endpoint_name)
  end 

  def method=(meth)
  end   

  def url=(endpoint_url) 
  end

  def param(param_name,param_value)
  end

  def call(api_name,api_endpoint,token,*extra_params)
  end

end

require_relative 'api_client_builder'

module SpotifyIntegration

  include APIClientBuilder

  def base_url
    'https://api.spotify.com/v1'
  end

  def random_state_string
    (0..10).map { (65 + rand(26)).chr }.join
  end

  api_client('spotify') do |apic|

    apic.api_endpoint('request_authorization') do |ep|
      ep.method = :get
      ep.url = "https://accounts.spotify.com/authorize"
      ep.param("client_id",SPOTIFY_KEY)
      ep.param("response_type","code")
      ep.param("redirect_uri","http://localhost:3000")
    end

    apic.api_endpoint('my_playlists') do |ep|
      ep.method = :get
      ep.url = "#{base_url}/me/playlists"
    end

  end

end

require 'integrations/spotify.rb'

class UsersController < ApplicationController

  include SpotifyIntegration

end

require 'rails_helper'

require 'integrations/spotify'

class SpotifyClientTester
  include SpotifyIntegration
end

RSpec.describe SpotifyIntegration do

  context 'Auxiliary methods' do

    it 'Two calls to random_state_string shall generate two different strings' do
      obj = SpotifyClientTester.new
      s1 = obj.random_state_string
      s2 = obj.random_state_string
      expect(s1).not_to eq(s2)
    end

  end

end

但当我运行它时，我得到了

未定义的本地变量或方法

base\u url

用于SpotifyIntegration:Module（nameferror）

我不确定我错过了什么。也许我应该使用

extend

而不是

include

。我总是对此感到困惑

---

有人能帮我找到正确的路吗？我已经与这个错误斗争了整整一个下午。

如果您想使用在模块

SpotifyIntegration

的类级别定义的方法，您需要扩展

APIClientBuilder

module SpotifyIntegration

  extend APIClientBuilder

---

另外，

base\u url

也必须是一个类方法，

def self.base\u url

如果要使用在模块

SpotifyIntegration

的类级别定义的方法，则需要扩展

APIClientBuilder

module SpotifyIntegration

  extend APIClientBuilder

---

另外，

base\u url

也必须是类方法，

def self.base\u url

您误用了mixin。对于经典继承不适合向对象添加一组特征的情况，请使用mixin

例如：

module Commentable
  extend ActiveSupport::Concern

  included do
    has_many :comments, as: :commentable
  end 
  # ...
end

class Video < ApplicationRecord
  include Commentable
end

class Hotel < ApplicationRecord
  include Commentable
end

---

为什么不将API客户机混合到控制器或模型中？因为单一责任原则和事实，使用较小的部分来做有限的事情比创建上帝类更可取

你误用了mixin。对于经典继承不适合向对象添加一组特征的情况，请使用mixin

例如：

module Commentable
  extend ActiveSupport::Concern

  included do
    has_many :comments, as: :commentable
  end 
  # ...
end

class Video < ApplicationRecord
  include Commentable
end

class Hotel < ApplicationRecord
  include Commentable
end

---

为什么不将API客户机混合到控制器或模型中？因为单一责任原则和事实，使用较小的部分来做有限的事情比创建上帝类更可取

它在哪一条线上失败了？您甚至没有在测试中调用

base\u url

方法，而且

random\u state\u string

也没有调用

base\u url

lib/integrations/spotify.rb:33

，这表示

ep.url=“{base\u url}/me/playlists”

。你说的正是我最困惑的地方。我甚至不调用

base\u url

。这不在这篇文章的片段中，

ep.url=“{base\u url}/me/playlists”

。抱歉，我现在编辑了它。我错误地删除了这个部分。这是在班级层面上的原因吗？api|U客户端（“spotify”）do | apic |----------在哪一行发生故障？您甚至没有在测试中调用

base\u url

方法，而且

random\u state\u string

也没有调用

base\u url

lib/integrations/spotify.rb:33

，这表示

ep.url=“{base\u url}/me/playlists”

。你说的正是我最困惑的地方。我甚至不调用

base\u url

。这不在这篇文章的片段中，

ep.url=“{base\u url}/me/playlists”

。抱歉，我现在编辑了它。我错误地删除了这个部分。这是在班级层面上的原因吗？api_client（“spotify”）do | apic |------------------在

SpotifyIntegration

中扩展它？在

SpotifyIntegration

中扩展它？是的，如果您不打算创建它的实例，客户端可以是一个模块。但在大多数情况下，您希望将客户机和服务对象设置为类，以便更容易通过初始值设定项注入配置。是的，如果您不打算创建其实例，则客户机可以是一个模块。但在大多数情况下，您希望将客户机和服务对象设置为类，以便更容易通过初始值设定项注入配置。