Question

我对rails非常陌生，我使用grape来构建API rails应用程序。

点击“创建活动”后，我收到了此错误消息。按钮： -

NameError at /events

undefined local variable or method `event_params' for #<EventsController:0x00000008f76400>

错误指向事件的控制器文件，

class EventsController < ApplicationController
   before_action :authenticate_user!
   before_action :authenticate_user_from_token!
   before_action :set_event, only: [:show, :edit, :update, :destroy]

 def index
   @events = Event.all
    if user_signed_in?
     if current_user.is_admin?
       @events = Event.all

       respond_to do |format|
         format.html
         format.json { render json: @events }
       end

     else
      @events = current_user.events
      respond_to do |format|
        format.html
        format.json { render json: @events }
      end
     end
   else
    render json: {}, status: :unauthorized
   end
 end

 def new
  @event = Event.new
 end

 def edit
 end

 def create
  @event = current_user.events.new(event_params)
  respond_to do |format|

     if @event.save
       format.html { redirect_to @event, notice: 'Event was successfully created.' }

       format.json { render :show, status: :created, location: @event }

     else
       format.html { render :show, notice: 'You are not allowed to view this.' }
       format.json { render json: {}, status: :unauthorized}
      end
    end
  end

这里是event_params方法，

def event_params
  params.require(:event).permit(:event_name, :event_description, :event_date, :event_time)
end

日志文件显示，

Started POST "/events" for 127.0.0.1 at 2015-08-10 14:38:16 +0800
Processing by EventsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"yRVn4uuxpMVejs/gsG004PIi2JRaWnovGBm7TweGgkf2XpTLzjOZNGanCRVVKSPAV6JzNRWmDzRRbq/dC2KOKQ==", "event"=>{"event_name"=>"ddwq", "event_description"=>"rqreqreqr", "event_date(1i)"=>"2015", "event_date(2i)"=>"8", "event_date(3i)"=>"10", "event_time(1i)"=>"2015", "event_time(2i)"=>"8", "event_time(3i)"=>"10", "event_time(4i)"=>"06", "event_time(5i)"=>"38"}, "commit"=>"Create Event"}
[1m[36mUser Load (1.6ms)[0m  [1mSELECT  "users".* FROM "users" WHERE "users"."id" = $1  ORDER BY "users"."id" ASC LIMIT 1[0m  [["id", 1]]
Completed 500 Internal Server Error in 34ms

NameError - undefined local variable or method `event_params' for #<EventsController:0x000000082a6540>:
app/controllers/events_controller.rb:37:in `create'
actionpack (4.2.0) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
...
...
bin/rails:4:in `<main>'

Started POST "/__better_errors/beb9cf3b65f0e36a/variables" for 127.0.0.1 at 2015-08-10 14:38:16 +0800

Answer 1

尝试构建而不是新建取代

@event = current_user.events.new(event_params)

通过

@event = current_u ser.events.build（event_params）`

Answer 2

def create
  @event = current_user.events.new(event_params)
  respond_to do |format|

     if @event.save
       format.html { redirect_to @event, notice: 'Event was successfully created.' }

       format.json { render :show, status: :created, location: @event }

     else
     respond_to do |format|
       format.html { render :show, notice: 'You are not allowed to view this.' }
       format.json { render json: {}, status: :unauthorized}
   end
 end ##You have missed the end here

这里是event_params方法，

def event_params
  params.require(:event).permit(:event_name, :event_description, :event_date, :event_time)
end

Answer 3

错误消息表明event_params方法无法使用EventsController方法。我认为您错误地将event_params置于另一个方法中或错过了end来结束create方法。它应该是EventsController类的实例方法。

此代码应该按原样运行：

class EventsController < ApplicationController
  before_action :authenticate_user!
  before_action :authenticate_user_from_token!
  before_action :set_event, only: [:show, :edit, :update, :destroy]

  def index
    @events = Event.all
    if user_signed_in?
      if current_user.is_admin?
        @events = Event.all

        respond_to do |format|
          format.html
          format.json { render json: @events }
        end

      else
        @events = current_user.events
        respond_to do |format|
          format.html
          format.json { render json: @events }
        end
      end
    else
      render json: {}, status: :unauthorized
    end
  end

  def new
    @event = Event.new
  end

  def edit
  end

  def create
    @event = current_user.events.new(event_params)
    respond_to do |format|

      if @event.save
        format.html { redirect_to @event, notice: 'Event was successfully created.' }

        format.json { render :show, status: :created, location: @event }

      else
        format.html { render :show, notice: 'You are not allowed to view this.' }
        format.json { render json: {}, status: :unauthorized}
      end
    end
  end

  private

  def event_params
    params.require(:event).permit(:event_name, :event_description, :event_date, :event_time)
  end
end

Answer 4

所以，错误是一个缺失的结束＆＃39;对于show not method我没有发布那个部分。

我完全错过了那个部分，因为错误是误导性的，我认为它与事件参数有关，因为错误指向那里。

/ events path处的NameError - 未定义的局部变量或方法

4 个答案: