检索在Rails类中定义的实例方法列表，不包括继承和包含的方法

Question

I have a class Product in my rails project, I am trying to retrieve a list of instance methods of my class that are defined in my file (not inherited method or included via mixin). Here's a small sample of my class :

class Product
  include Mongoid::Document
  include Mongoid::Paperclip
  include Mongoid::Search
  include Mongoid::Slug
  include Mongoid::Timestamps
  extend Enumerize
    def product_image
    image.url(:small) unless image.nil?
  end

  def product_school_level
    self.school_levels.join ' | '
  end

  def product_grades
    self.grades.where(degree_ids: nil).pluck(:name).uniq.join ' | '
  end
end

I tried to use Product.instance_methods(false) . However this still returns a lot of methods I dont need, here's a little sample : :_run_post_process_callbacks, :aliased_fields, :_post_process_callbacks, :_run_image_post_process_callbacks, :_image_post_process_callbacks, :_validation_callbacks, :nested_attributes?, :_run_touch_callbacks, :readonly_attributes?, :_run_save_callbacks, :aliased_fields?, :_save_callbacks, :localized_fields?, :readonly_attributes, :fields?, :pre_processed_defaults?, :_update_callbacks, :post_processed_defaults?, :fields, : _id_default

I ran Product.new.method(:_run_post_process_callbacks).source_location on a few of these methods to try to check where they come from. It seems they all come from active_support. I never included active_support in my class, so I guess classes in a rails project automatically include active_supports methods ? How is that possible without any inheritance syntax (<<) or include syntax ? How can I then achieve what I want to do and get rid of these methods I dont need in my list ?

Answer 1

Many (most? all?) of those extra methods you are seeing are being created using Module#define_method . If you dig deep in the source for active_support , you'll see that. (You aren't directly including active_support , but it's being pulled in by one or more of the Mongoid modules.)

So these are in fact valid instance methods of your model class, which is why they are included in instance_methods(false) . Other methods that are defined "conventionally" in the mixins, such as #freeze , are reported by instance_methods(true) , but not by instance_methods(false) .

I think you may have to do something to filter the list based on the source location. Something along these lines:

my_methods = Product.instance_methods(false).select do |m|
  Product.instance_method(m).source_location.first.ends_with? '/product.rb'
end