ruby - How to find or update a record though a nested attributes form (Rails 6)

Question

tldr: How do I find and update or create a record through a nested association?

I have a Registrations model that belongs to a Lead model. Leads are created via nested attributes when the user submits the registration form. This works fine, but now I need to update the Registration so that it either creates a new lead, OR finds and updates the lead if a lead already exists with that email.

registration.rb:

class Registration < ApplicationRecord
  belongs_to :showing
  belongs_to :lead

  accepts_nested_attributes_for :lead
  validates_associated :lead

end

lead.rb

class Lead < ApplicationRecord
  belongs_to :account
  has_many :registrations, dependent: :destroy
  has_many :showings, through: :registrations
  validates :name, :email, :phone, presence: true

end

registrations_controller.rb

class RegistrationsController < ApplicationController
  before_action :set_account

  def index
    redirect_to new_showing_registration_path
  end

  def new
    @registration = @showing.registrations.build
    @lead = Lead.new
  end

  def create
    @showing = Showing.find(params[:showing_id])
    @registration = @showing.registrations.build(registration_params)
    if @registration.save
      redirect_to new_showing_registration_path, notice: 'Thank you for registering.'
    else
      render :new, status: :unprocessable_entity
    end
  end

  def show
    redirect_to new_showing_registration_path
  end

  def edit
    @showing = Showing.find(params[:showing_id])
    @registration = Registration.find(params[:id])
    @account_id = @showing.listing.account.id.to_i
  end

  def update
    @registration = Registration.find(params[:id])
    if @registration.update(registration_params)
      redirect_to new_showing_registration_path, notice: 'Thank you for registering.'
    else
      render :edit, status: :unprocessable_entity
    end
  end

  private
    def registration_params
      params.require(:registration).permit(lead_attributes: [:account_id, :id, :name, :email, :phone, :agent, :mortgage, :source])
    end

    def set_account
      @showing = Showing.find(params[:showing_id])
      @account_id = @showing.listing.account.id.to_i
    end
end

question from:https://stackoverflow.com/questions/65927813/how-to-find-or-update-a-record-though-a-nested-attributes-form-rails-6

Answer 1

maybe this one will help

https://stackoverflow.com/a/3580267/11544219

or this

https://dev.to/katkelly/why-yes-i-ll-accept-those-nested-attributes-18f7

class Registration < ApplicationRecord
  belongs_to :showing
  belongs_to :lead

  accepts_nested_attributes_for :lead
  validates_associated :lead

  def autosave_associated_records_for_lead
   existed_lead = Lead.find_by(registration: self)
   if existed_lead.present?
     existed_lead.update!(lead.attributes)
   else
     lead.save!
   end
  end

end