How do I elegantly handle two-sided relations with Rails translations? - ruby-on-rails

Question

I have a family_tree and someone can add their relatives to the tree.
So what happens is there is a membership record created for each family_tree entry.
However, if a Son adds a Dad, we should be able to update the family tree of the Dad to add the "Son" to the tree in the view. What's the best Rails way to approach this? I know Rails does a lot of translations natively, and pluralizations, etc. Anyway for me to leverage that for what I want to do?
Also, what is the class/module that handles that stuff again? ActiveSupport?
This is my User model:
# == Schema Information
#
# Table name: users
#
# id :integer not null, primary key
# email :string(255) default(""), not null
# encrypted_password :string(255) default(""), not null
# reset_password_token :string(255)
# reset_password_sent_at :datetime
# remember_created_at :datetime
# sign_in_count :integer default(0), not null
# current_sign_in_at :datetime
# last_sign_in_at :datetime
# current_sign_in_ip :string(255)
# last_sign_in_ip :string(255)
# created_at :datetime
# updated_at :datetime
# name :string(255)
# confirmation_token :string(255)
# confirmed_at :datetime
# confirmation_sent_at :datetime
# unconfirmed_email :string(255)
# invitation_relation :string(255)
# avatar :string(255)
#
class User < ActiveRecord::Base
has_one :family_tree, dependent: :destroy
has_many :memberships, dependent: :destroy
has_many :nodes, dependent: :destroy
has_many :participants, dependent: :destroy
end
FamilyTree.rb
# == Schema Information
#
# Table name: family_trees
#
# id :integer not null, primary key
# name :string(255)
# user_id :integer
# created_at :datetime
# updated_at :datetime
#
class FamilyTree < ActiveRecord::Base
belongs_to :user
has_many :memberships, dependent: :destroy
has_many :members, through: :memberships, source: :user, dependent: :destroy
has_many :nodes, dependent: :destroy
end
Membership.rb:
# == Schema Information
#
# Table name: memberships
#
# id :integer not null, primary key
# family_tree_id :integer
# user_id :integer
# created_at :datetime
# updated_at :datetime
# relation :string(255)
#
class Membership < ActiveRecord::Base
belongs_to :family_tree
belongs_to :user
end
Node.rb
# == Schema Information
#
# Table name: nodes
#
# id :integer not null, primary key
# name :string(255)
# family_tree_id :integer
# user_id :integer
# media_id :integer
# media_type :string(255)
# created_at :datetime
# updated_at :datetime
# circa :datetime
# is_comment :boolean
#
class Node < ActiveRecord::Base
belongs_to :family_tree
belongs_to :user
belongs_to :media, polymorphic: true, dependent: :destroy
has_many :comments, dependent: :destroy
has_many :node_comments, dependent: :destroy
end
My _tree.html.erb looks like this (truncated for brevity):
<li class="tree-item-name">Great Grandparents
<ul>
<li><% if relative.humanize == "Great Grandfather" || relative.humanize == "Great Grandmother" %>
<%= link_to image_tag(membership.user.avatar.url, size: "48x48", :class => "img-circle") , family_tree_path(membership.user.family_tree), :target => '_blank' %>
<%= link_to membership.user.name, family_tree_path(membership.user.family_tree), :target => '_blank'%>
<% else %>
None added yet, add them <%= link_to 'here', "#" , class: 'btn invite popupbox','data-popup' => 'invite_friend' %>
<% end %>
</li>
</ul>
</li>
<li class="tree-item-name">Grandparents
<ul>
<li><% if relative.humanize == "Grandfather" || relative.humanize == "Grandmother" %>
<%= link_to image_tag(membership.user.avatar.url, size: "48x48", :class => "img-circle") , family_tree_path(membership.user.family_tree), :target => '_blank' %>
<%= link_to membership.user.name, family_tree_path(membership.user.family_tree), :target => '_blank' %>
<% else %>
None added yet, add them <%= link_to 'here', "#" , class: 'btn invite popupbox','data-popup' => 'invite_friend' %>
<% end %>
</li>
</ul>
</li>

Answer 1

I would use the same relations you defined in the question, except this part:
class Membership < ActiveRecord::Base
belongs_to :family_tree
belongs_to :user_one, class_name: 'User'
belongs_to :user_two, class_name: 'User' # I actually have no idea how to call them!
belongs_to :relation # to hold values likes 'Son', 'Dad', etc.
# The model Relation would be as simple as a name and internal reference, nothing else.
# (internal_reference is here to solve the translation problems and other stuff you will understand with the following code)
With a callback after_create to reverse the membership created:
def create_reverse_membership
user_one_is_female = user_one.gender == 'female'
user_two_is_female = user_two.gender == 'female'
son_or_daughter = user_one_is_female ? :daughter : :son
father_or_mother = user_two_is_female ? :mother : :father
case relation.internal_reference.to_sym
when :son
relation = Relation.find_by_internal_reference(father_or_mother)
membership = Membership.where(relation_id: relation.id, user_one: user_two.id, user_two: user_one.id).first
if membership.present?
# This means the reverse membership already exists, do not call Membership.create here because it would cause and endless loop with the callback
else
membership = Membership.create(relation_id: relation.id, user_one: user_two, user_two: user_one)
end
when :father
# almost same logic but with `son_or_daughter`
when :mother
else
end
end
English not being my native language, this code probably lacks of consistency (coherence, logic).
Hope this helps!