为什么我不能访问我的类实例方法？

Question

I'm trying to access the ApiClient class instance methods from within the MethodLogger module. Methods return empty every time.

require 'faraday'

module Assets
  module MethodLogger
    def self.included(base)
      methods = base.instance_methods(false)
      puts base # returns Assets::ApiClient
      puts methods.length # returns 0
    end
  end

  class ApiClient
    include MethodLogger

    def initialize(url, username = nil, password = nil)
      @connection = Faraday.new(url) do |faraday|
        faraday.basic_auth(username, password) if username
        faraday.request :url_encoded
        faraday.response :logger
        faraday.adapter :net_http
        faraday.use Errors::RaiseError
      end
    end

    def get(path, parameter = nil)
      @connection.get path, parameter
    end

    def post(path, data, headers = {})
      @connection.post path, data, headers
    end

    def put(path, data, headers = {})
      @connection.put path, data, headers
    end

    def delete(path)
      @connection.delete path
    end
  end
end

I thought that perhaps the base was incorrect, but it is correctly returning Assets::ApiClient.

Any ideas what may be wrong?

Answer 1

Your included method is called as soon as the module is included (ie as part of the include MethodLogger ) call

At that point the class does have no instance methods of its own - you only define those a couple of lines later.

Answer 2

If you take a look at the documentation of included :

module A
  def A.included(mod)
    puts "#{self} included in #{mod}"
  end
end
module Enumerable
  include A
end
 # => prints "A included in Enumerable"

The method is called in your line include MethodLogger and at this point you don't have any method defined.