ruby-on-rails - 分配属性时，必须传递一个散列作为参数

Question

我正在关注 Rails 4 的敏捷 Web 开发。第 9 章购物车创建。当我想更新购物车时，我收到以下错误通知:分配属性时，您必须将散列作为参数传递。购物车 Controller #更新。

class CartsController < ApplicationController
  include CurrentCart
  before_action :set_cart, only: [:show, :edit, :update, :destroy]
  rescue_from ActiveRecord::RecordNotFound, with: :invalid_cart

  def index
    @carts = Cart.all
  end

  def show
  end

  def new
    @cart = Cart.new
  end

  def edit
  end

  def create
    @cart = Cart.new(cart_params)

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

  def update
    @cart = Cart.find(params[:id])

    respond_to do |format|
      if @cart.update_attributes(params[:cart])
        format.html { redirect_to @cart, notice: 'Cart was successfully updated.' }
        format.json { render :show, status: :ok, location: @cart }
      else
        format.html { render :edit }
        format.json { render json: @cart.errors, status: :unprocessable_entity }
      end
    end
  end

  def destroy
    @cart.destroy if @cart.id == session[:card_id]
    session[:card_id] = nil
    respond_to do |format|
      format.html { redirect_to store_url, notice: 'Your cart is currently empty.' }
      format.json { head :no_content }
    end
  end

  private

  def set_cart
    @cart = Cart.find(params[:id])
  end

  def cart_params
    params[:cart]
  end

  def invalid_cart
    logger.error "Attempt to access invalid cart #{params[:id]}"
    redirect_to store_url, notice: 'Invalid cart'
  end
end

Answer 1

您的参数可能是 ActionController::Parameters 的一个实例

如果是这样，您需要允许要使用的属性，如下所示:

def cart_params
  params.require(:cart).permit(:attribute1, :attribute2, :attribute3)
end