如何通过嵌套属性表单查找或更新记录（Rails 6）答案

【问题标题】：How to find or update a record though a nested attributes form (Rails 6)如何通过嵌套属性表单查找或更新记录（Rails 6）
【发布时间】：2021-01-27 21:40:48
【问题描述】：

tldr：如何查找和更新或通过嵌套关联创建记录？

我有一个属于 Lead 模型的 Registrations 模型。当用户提交注册表单时，潜在客户是通过嵌套属性创建的。这工作正常，但现在我需要更新注册，以便它创建新的潜在客户，或者如果该电子邮件已存在潜在客户，则查找并更新潜在客户。

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

【问题讨论】：

标签： ruby-on-rails ruby ruby-on-rails-6

【解决方案1】：

也许这个会有所帮助

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

或者这个

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

【讨论】：

谢谢！这很接近，但是当覆盖自动保存时，我开始遇到在父级上设置lead_id的问题。不完全确定为什么。因此，我决定使用您的类似逻辑进行回调。如果您有兴趣，我发布了我的解决方案。再次感谢！
哦，回调也有效。确定伙计

【解决方案2】：

对于正在开发类似功能的其他人，这是我解决它的方法（下）。最终，我选择使用回调而不覆盖自动保存方法。覆盖自动保存方法时，我在连接表的父对象上设置嵌套对象 ID 时遇到问题。所以，我采用了以下回调过程：

检查该电子邮件是否存在潜在客户
如果存在，则使用新的潜在客户属性更新现有潜在客户
将新潜在客户设置为更新后的现有潜在客户
如果线索不存在，则将新线索传回控制器进行创建

class Registration < ApplicationRecord
  belongs_to :showing
  belongs_to :lead
  accepts_nested_attributes_for :lead, :reject_if => :all_blank, allow_destroy: true
  before_validation :update_or_create_lead

  private

  def update_or_create_lead
    existing = Lead.find_by(email: self.lead.email)
    if existing
      existing.update(
        name: lead.name,
        phone: lead.phone,
        agent: lead.agent,
        mortgage: lead.mortgage,
        source: lead.source
    )
      self.lead = existing
    else
      self.lead
    end
  end

end

【讨论】：