如何在rails中通過嵌套路由創建新對象？

Question

所以，以下是我定義我的應用程序的路由方式：

Rails.application.routes.draw do 
    resources :operators do 
     resources :cabs 
    end 
end 

如所理解的，我的應用程序有一些出租車運營商和每個運營商都有駕駛室一定數量的與他們有聯繫：

class Operator < ActiveRecord::Base 
    has_many :cabs 
end 

當我試圖創建一個新的駕駛室，因爲這個問題是：

<%= link_to 'New Cab', new_operator_cab_path %> 

新型駕駛室創作形式如下：

<%= form_for @cab, url: operator_cabs_path, method: :post do |f| %> 
        <% if @cab.errors.any? %> 
        <div id="error_explanation"> 
         <h2><%= pluralize(@cab.errors.count, "error") %> prohibited this cab from being saved:</h2> 

         <ul> 
         <% @cab.errors.full_messages.each do |message| %> 
         <li><%= message %></li> 
         <% end %> 
         </ul> 
        </div> 
        <% end %> 

        <div class="field"> 
        <%= f.label :category %><br> 
        <%= f.text_field :category %> 
        </div> 
        <div class="field"> 
        <%= f.label :number %><br> 
        <%= f.text_field :number %> 
        </div> 
        <div class="actions"> 
        <%= f.submit %> 
        </div> 
       <% end %> 

我不得不顯式定義url和表單中的方法，默認url（cabs_path）根據路由定義的方式不存在。 雖然我的鏈接工作正常，但沒有新的駕駛室被創建。以下是我的cabs_controller：

class CabsController < ApplicationController 
    before_action :set_cab, only: [:show, :edit, :update, :destroy] 

    # GET /cabs 
    # GET /cabs.json 
    def index 
    @cabs = Operator.find(params[:operator_id]).cabs 
    end 

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

    # GET /cabs/new 
    def new 
    @cab = Cab.new 
    @operator = Operator.find(params[:operator_id]) 
    end 

    # GET /cabs/1/edit 
    def edit 
    @operators = Operator.all 
    end 

    # POST /cabs 
    # POST /cabs.json 
    def create 
    @cab = Cab.new(cab_params) 

    respond_to do |format| 
     if @cab.save 
     format.html { redirect_to operator_cabs_path, notice: 'Cab was successfully created.' } 
     format.json { render :show, status: :created, location: @cab } 
     else 
     format.html { render :new } 
     format.json { render json: @cab.errors, status: :unprocessable_entity } 
     end 
    end 
    end 

    # PATCH/PUT /cabs/1 
    # PATCH/PUT /cabs/1.json 
    def update 
    respond_to do |format| 
     if @cab.update(cab_params) 
     format.html { redirect_to operator_cabs_path(operator_id: @operator.id), notice: 'Cab was successfully updated.' } 
     format.json { render :show, status: :ok, location: @cab } 
     else 
     format.html { render :edit } 
     format.json { render json: @cab.errors, status: :unprocessable_entity } 
     end 
    end 
    end 

    # DELETE /cabs/1 
    # DELETE /cabs/1.json 
    def destroy 
    @cab.destroy 
    respond_to do |format| 
     format.html { redirect_to operator_cabs_path(operator_id: @operator.id), notice: 'Cab was successfully destroyed.' } 
     format.json { head :no_content } 
    end 
    end 

    private 
    # Use callbacks to share common setup or constraints between actions. 
    def set_cab 
     @cab = Cab.find(params[:id]) 
     @operator = Operator.find(params[:operator_id]) 
    end 

    # Never trust parameters from the scary internet, only allow the white list through. 
    def cab_params 
     params.require(:cab).permit(:category, :number) 
    end 
end 

Answer 1

的幾個問題和指針：

• 貴駕駛室模型包括belongs_to :operator，以及一個operator_id整數類型的列？
• 您的new_operator_cab_path需要告知駕駛室屬於哪個操作員，如下所示：new_operator_cab_path(@operator)。
• 您的表單網址中存在與上述相同的問題：@cab, url: operator_cabs_path。在這種情況下，您可以簡單地通過將其替換爲[@cab.operator, @cab]來修復它，Rails將轉換爲適當的URL。
• 由於這是一個嵌套的資源，所以您需要以不同的方式構建新的出租車。而不是在您的新和創建的行動，你會想要使用Operator.find(params[:operator_id]).cabs.build。這將專門構建屬於您的運營商的出租車。

這裏有一些相關的資源，你可能會發現有用：

• Rails Association Basics
• Rails Routing: Creating Paths and URLs from Objects