ruby-on-rails - 使用accepts_nested_attributes_for时不能为空(Rails 4)

Question

我有两个模型:我有一个嵌套表单，允许用户输入 @contact 和 @goal 的属性。但是，当我去保存表单输入时，出现以下错误:

1 error prohibited this contact from being saved:
Goals contact can't be blank

这是我的目标和联系模型，以及联系 Controller :

class Contact < ActiveRecord::Base

  belongs_to :user
  has_many :goals
  accepts_nested_attributes_for :goals, allow_destroy: true
  validates_presence_of :user_id,:name,:title,:email
end

class Goal < ActiveRecord::Base
  belongs_to :contact
  validates_presence_of :title, :due_date, :contact_id
end

class ContactsController < ApplicationController
  before_action :set_contact, only: [:show, :edit, :update, :destroy]

  # GET /contacts
  # GET /contacts.json
  def index
    @contacts = current_user.contacts
  end

  # GET /contacts/1
  # GET /contacts/1.json
  def show
  end

  # GET /contacts/new
  def new
    @contact = Contact.new
    1.times { @contact.goals.build }
  end

  # GET /contacts/1/edit
  def edit
  end

  # POST /contacts
  # POST /contacts.json
  def create
    @contact = Contact.new(contact_params.merge(user_id: current_user.id))
    respond_to do |format|
      if @contact.save
        format.html { redirect_to @contact, notice: 'Contact was successfully created.' }
        format.json { render :show, status: :created, location: @contact }
      else
        format.html { render :new }
        format.json { render json: @contact.errors, status: :unprocessable_entity }
      end
    end
  end

  # PATCH/PUT /contacts/1
  # PATCH/PUT /contacts/1.json
  def update
    respond_to do |format|
      if @contact.update(contact_params)
        format.html { redirect_to @contact, notice: 'Contact was successfully updated.' }
        format.json { render :show, status: :ok, location: @contact }
      else
        format.html { render :edit }
        format.json { render json: @contact.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /contacts/1
  # DELETE /contacts/1.json
  def destroy
    @contact.destroy
    respond_to do |format|
      format.html { redirect_to contacts_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_contact
      @contact = Contact.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def contact_params
      params.require(:contact).permit(:name, :title, :company, :email, :notes, goals_attributes: [:title, :due_date, :notes, :contact_id])
    end
end

我确保将目标属性添加到联系人参数(在联系人 Controller 中)。对可能出现的问题有什么想法吗？这是该项目的链接:https://github.com/nowgeez/radiusapp

谢谢!

Answer 1

我找到了另一个解决方案。您可以在 has_many 和 belongs_to 中使用 inverse_of 选项:

class Contact < ActiveRecord::Base
  has_many :goals, inverse_of: :contact
end

class Goal < ActiveRecord::Base
  belongs_to :contact, inverse_of: :goals
  validates_presence_of :title, :due_date, :contact
end

我不知道它到底为什么起作用，但我相信这是因为它允许在目标验证之前正确设置 contact_id。

我在阅读这篇博文时找到了解决方案:http://homeonrails.com/2012/10/validating-nested-associations-in-rails/