Ruby-on-rails 分配属性时，必须传递一个散列作为参数
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When assigning attributes, you must pass a hash as an argument
提问by Keeic
I am following Agile Web Development with Rails 4. Chapter Cart 9 Cart Creation. When I want to update a cart, I get the following Error Notification: When assigning attributes, you must pass a hash as an arguments. CartController#update.
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。购物车控制器#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
采纳答案by Robert Falkén
Your params is probably an instance of ActionController::Parameters
你的参数可能是ActionController::Parameters 的一个实例
If so, you need to permit the attributes you want to use, like so:
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
回答by Aaditi Jain
Try this: In your update method replace
试试这个：在你的更新方法中替换
if @cart.update_attributes(params[:cart])
by
经过
if @cart.update_attributes(cart_params)
In your cart_params private method do this:
在您的 cart_params 私有方法中执行以下操作：
def cart_params
params.require(:cart).permit(:attribute1, :attribute2, :attribute3)
end
With Rails 4, the concept of strong parameters has been introduced which basically forbids mass assignment of attributes in the controller. This means that the mass assingment protection that was once in model (attr_accessible) has now been moved to the controller. Hence in your models you no moreneed to use this:
在 Rails 4 中，引入了强参数的概念，它基本上禁止在控制器中大量分配属性。这意味着曾经在模型 (attr_accessible) 中的质量评估保护现在已移至控制器。因此，在您的模型中，您不再需要使用它：
attr_accessible :attribute1, attribute 2 #attributes that can be mass-assinged
attr_protected :attribute3 #attribute that is protected and cannot be mass-assinged
Instead you can now do this in your controller through :
相反，您现在可以通过以下方式在控制器中执行此操作：
params.require(:cart).permit(:attribute1, :attribute2, :attribute3)
This means that only attribute1, attribute2. attribute3 of cart are accessible while other are protected attributes
这意味着只有attribute1、attribute2。购物车的属性 3 是可访问的，而其他属性是受保护的属性
