Rails最佳实践：模型中的关联对象创建

Question

I have bassicly 3 tables : Users (email, password), Contacts (name, phone), Relations (user_id, contact_id, level) .

When a user creates a new contact, i want him to be associated to it. The association has 1 to 3 as level of "friendship".

I use a form to input the level in my contacts#create controller.

For now, i have this which works great

  def create
    @contact = Contact.new(params[:contact])
    if @contact.save
      #@relation = Relation.new(:user_id => current_user.id, :contact_id => @contact.id, :level => params[:relation])
      #@relation.save
      redirect_to root_url, :notice => "ok!"
    else
      render "new"
    end
  end

I was thinking of moving the relation creation to my contact model to do something like this :

  after_create { Relation.create(user_id: current_user.id, contact_id: self.id, level: params[:relation]) }

Of course, this does not work, but you get the idea. Would it be good to that in the model or can i keep it as i do for now

cheers

Answer 1

Something like this? Basically just create the relation and contact all in one, associated to the current_user.

current_user.relations.create(contact: Contact.new(params[:contact]), level: params[:relation])

Don't move it to an after_create. If anything create a function somewhere that accepts a user, a contact and a relation.

Answer 2

I would rather keep it in the controller as you have it. For testing (and potentially other) purposes, you may not want to have Users and Contacts tied together so closely. The way I see it is that the controller is the place to tie together creation logic, and methods like after_create in the model are more to set certain parameters, rather than create new associations, which, in the future you may not necessarily want.

tl;dr - Putting something like this in the controller couples the two models together far too tightly.

Answer 3

contact.rb

has_one :relation
accepts_nested_attributes_for :relation

relation

belongs_to :contact
belongs_to :user

Views like

= for_form @contact do |f|
  = f.fields_for :relation do |r|
    = r.text_field :level
  = f.submit 'create'

controller new action

  @contact = Contact.new
  @contact.build_relation # create new relation object for the contact

controller create action

  @contact = Contact.new(params[:contact])
  @contact.relation.user = current_user
  @contact.save