尝试构建一个路由，该路由可以显示包含各种类型糖果的各种信息的页面。

路由识别URL路径，但希望它只显示有效的糖果类型，例如kit_kat，gummy_bear，twizzler指定的任何其他类型的糖果应生成404状态代码

生成了一个脚手架，允许任何人添加糖果类型，但当我尝试传递有效的糖果类型（kit_kat等）时，我得到了错误

Rails 4.2 CandiesController中的NameError#为创建未定义的局部变量或方法“params”#

**candy_controller.rb**

class CandiesController < ApplicationController
  before_action :set_candy, only: [:show, :edit, :update, :destroy]

  # GET /candies
  # GET /candies.json
  def index
    @candies = Candy.all
  end

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

  # GET /candies/new
  def new
    @candy = Candy.new
  end


  # GET /candies/1/edit
  def edit
  end

  # POST /candies
  # POST /candies.json
  def create
    if (([:kit_kat, :skittles, :m_and_ms, :herseys_kiss, :butterfinger, :gummy_bear,
      :twizzler]).any? { |word| params[:title].includes?(word) })


    @candy = Candy.new(candy_params)

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

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

  # DELETE /candies/1
  # DELETE /candies/1.json
  def destroy
    @candy.destroy
    respond_to do |format|
      format.html { redirect_to candies_url, notice: 'Candy was successfully destroyed.' }
      format.json { head :no_content }
    end
  end

  private

    def set_candy
      @candy = Candy.friendly.find(params[:id])
    end
    # Use callbacks to share common setup or constraints between actions.


    # Never trust parameters from the scary internet, only allow the white list through.
    def candy_params
      params.require(:candy).permit(:title, :discription)
    end
end

candy.rb

class Candy < ActiveRecord::Base

  extend FriendlyId
  friendly_id :title, use: :slugged 

end

更新了candy/U控制器。铷

    def create
        if candy[:title] && !candy[:title].empty? && [:kit_kat, :skittles, :m_and_ms, :herseys_kiss, :butterfinger, :gummy_bear,
          :twizzler].include?(candy[:title].to_sym)

        @candy = Candy.new(candy_params)

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

updated code

def create
  if candy_params[:title] && !candy_params[:title].empty? && [:kit_kat, :skittles, :m_and_ms, :herseys_kiss, :butterfinger, :gummy_bear,
      :twizzler].include?(candy_params[:title].to_sym)


    @candy = Candy.new(candy_params)

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