问Rails:适用于三个用户的基本pundit gem设置

EN

class ItemsController < ApplicationController
  before_action :set_item, only: [:show, :edit, :update, :destroy]


  def index
    authorize @item
    @items = Item.all
  end

  def show
    authorize @item
    @comments = Comment.where(item_id: @item).order("created_at DESC")
    @items = Item.find(params[:id])
    end

  def new
    authorize @item
    @item = Item.new
    @categories = Category.order(:name)
  end


  def edit
    authorize @item
    @categories = Category.order(:name)
  end

  def create
    authorize @item
    @item = Item.new(item_params)

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


  def update
    authorize @item
    respond_to do |format|
      if @item.update(item_params)
        format.html { redirect_to @item, notice: 'Item was successfully updated.' }
        format.json { render :show, status: :ok, location: @item }
      else
        format.html { render :edit }
        format.json { render json: @item.errors, status: :unprocessable_entity }
      end
    end
  end


  def destroy
    authorize @item
    @item.destroy
    respond_to do |format|
      format.html { redirect_to items_url, notice: 'Item was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private
    def set_item
      @item = Item.find(params[:id])
    end
end

class ApplicationController < ActionController::Base
  include Pundit
  protect_from_forgery prepend: true

  rescue_from Pundit::NotAuthorizedError, with: :user_not_authorized

  def pundit_user
    CurrentContext.new(current_seller, current_admin, current_viewer)
  end

  private

  def user_not_authorized(exception)
    policy_name = exception.policy.class.to_s.underscore
    flash[:warning] = t "#{policy_name}.#{exception.query}", scope: "pundit", default: :default
    redirect_to(request.referrer || root_path)
  end
end

class CurrentContext
  attr_reader :seller, :admin, :viewer

  def initialize(seller, admin, viewer)
    @seller = seller
    @admin = admin
    @viewer = viewer
  end
end

class ApplicationPolicy
  attr_reader :seller, :record, :admin, :viewer

  def initialize(context, record)
     raise Pundit::NotAuthorizedError, "must be logged in" unless context
    @seller = context.seller
    @admin = context.admin
    @viewer = context.viewer
    @record = record
  end

  def index?
    false
  end

  def show?
    scope.where(:id => record.id).exists?
  end

  def create?
   false
  end

  def new?
    create?
  end

  def update?
    false
  end

  def edit?
    update?
  end

  def destroy?
    false
  end

  def scope
    Pundit.policy_scope!(user, record.class)
  end

  class Scope
    attr_reader :seller, :admin, :viewer, :scope

    def initialize(context, scope)
      @seller = context.seller
      @admin = context.admin
      @viewer = context.viewer
      @scope = scope
    end

    def resolve
      scope
    end
  end
end

class ItemPolicy < ApplicationPolicy
  attr_reader :item

  def initialize(user, item)
    super(user, item)
    @user = user
    @item = record
  end

  def update?
    @user.is_a?(Admin) || @item.try(:user) == @user
  end

  def index?
    @user.is_a?(Admin) || @item.try(:user) == @user
  end

  def show?
    @user.is_a?(Admin) || @item.try(:user) == @user
  end

  def create?
    @user.is_a?(Admin) || @item.try(:user) == @user
  end

  def new?
    @user.is_a?(Admin) || @item.try(:user) == @user
  end

  def edit?
    @user.is_a?(Admin) || @item.try(:user) == @user
  end

  def destroy?
   @user.is_a?(Admin) || @item.try(:user) == @user
  end
end