如何遍历Rails模型的嵌套属性？

Question

I have a collection of models: Users, Cvs, Skills, Educations, & Experiences.

# models/user.rb
class User < ApplicationRecord
  has_one :cv
  has_many :skills, through: :cv, inverse_of: :user
  has_many :educations, through: :cv, inverse_of: :user
  has_many :experiences, through: :cv, inverse_of: :user
  ...
end

# models/cv.rb
class Cv < ApplicationRecord
  belongs_to :user
  has_many :skills
  has_many :educations
  has_many :experiences
  ...
end

# models/skill.rb
class Skill < ApplicationRecord
  belongs_to :cv
  belongs_to :user, inverse_of: :skill
end

# models/education.rb
class Education < ApplicationRecord
  belongs_to :cv
  belongs_to :user, inverse_of: :education
end

# models/experience.rb
class Experience < ApplicationRecord
  belongs_to :cv
  belongs_to :user, inverse_of: :experience
end

So, basically, a user has 1 cv and many skills , educations , and experiences that are nested in that cv

A Cv has many attributes other than the nested skills , educations , and experiences .

How can I iterate through all of the attributes in a Cv, including the nested ones? I tried this:

@user = User.new

@user.build_cv
@user.cv.educations.build
@user.cv.experiences.build
@user.cv.skills.build

@user.cv.attributes.each_pair do |attr, value|
  puts "#{attr}: #{value}"
end

But this just lists the attributes that are directly in the Cv model and not the attributes for the Cv's education , skill , and experience . What I eventually need to do is iterate through the Cv attributes and it's nested attributes searching for blank values in order to make sure a Cv has been completed. I could do that with a simple .blank? on each attribute if I could just figure out how to iterate through them all.

So far, this is the most concise way I came up with to do it, I was just hoping that there was a built-in helper method for something like this:

def is_complete?
  user = current_user
  user.cv.attributes.each do |attr|
    return false if attr.blank?
  end
  user.cv.skills.each do |skill|
    skill.attributes.each do |sa|
      return false if sa.blank?
    end
  end
  user.cv.educations.each do |edu|
    edu.attributes.each do |ea|
      return false if ea.blank?
    end
  end
  user.cv.experiences.each do |exp|
    exp.attributes.each do |exa|
      return false if edu.blank?
    end
  end
  true
end

Answer 1

You can use reflect_on_all_associations

Cv.reflect_on_all_associations(:has_many).map(&:name).each do |attr|
  if @user.cv.send(attr).blank?
    # do something
  end
end

If you want to check individual attribute elements...

Cv.reflect_on_all_associations(:has_many).map(&:name).each do |attr|
  @user.cv.send(attr).each do |item|
    if item.blank?
      # do something
    end
  end
end

or if you're looking at checking each attribute of each item...

If you want to check individual attribute elements...

Cv.reflect_on_all_associations(:has_many).map(&:name).each do |attr|
  @user.cv.send(attr).each do |item|
    item.attributes.each_pair do |subattr, value|
      puts "#{item.class}.#{subattr}: #{value}"
    end
  end
end

But a more natural way to do this would be to put validations on the association models.