Question

所以我刚刚完成了One Month Rails，在最后两个视频的某个地方，我在登录时停止了创建新的引脚。

当用户登录并尝试添加新图钉时会出现此问题。

这是我得到的错误：

NoMethodError in PinsController#create
undefined method `name' for #<Pin:0x41e0c08>
Extracted source (around line #22):   
def create
@pin = current_user.pins.build(pin_params)
if @pin.save
  redirect_to @pin, notice: 'Pin was successfully created.'
else
  render action: 'new'

pins_controller.rb

class PinsController < ApplicationController
before_action :set_pin, only: [:show, :edit, :update, :destroy]
before_action :correct_user, only: [:edit, :update, :destroy]
before_action :authenticate_user!, except: [:index, :show]

def index
@pins = Pin.all.order("created_at DESC").paginate(:page => params[:page], :per_page =>    20)
end

def show
end

def new
@pin = current_user.pins.build
end

def edit
end

def create
@pin = current_user.pins.build(pin_params)
if @pin.save
  redirect_to @pin, notice: 'Pin was successfully created.'
else
  render action: 'new'
end
end

user.rb

class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :token_authenticatable, :confirmable,
# :lockable, :timeoutable and :omniauthable
devise :database_authenticatable, :registerable,
     :recoverable, :rememberable, :trackable, :validatable

has_many :pins, dependent: :destroy

validates :name, presence: true
validates :name, length: { minimum: 2 }
end

编辑所以我按照Doon的建议检查模型，并将其更改为：

user.rb

has_many :pins, dependent: :destroy

validates :name, presence: true
validates :name, length: { minimum: 2 }

pin.rb

validates :image, presence: true
validates :description, presence: true

这似乎消除了第一条错误消息，但现在我看到了一条新消息：

NameError in Pins#show
undefined local variable or method `pin' for #<#<Class:0x3e41920>:0x4e1bbe8>

来自show.html.erb

<% if current_user && pin.user == current_user %>
<%= link_to edit_pin_path(@pin) do %>
<span class="glyphicon glyphicon-pencil"></span>
Edit
<% end %>
<% end %>

帮助（再次）？

Answer 1

您似乎正在name模型中的某个位置访问字段Pin但是name表中的字段pins或虚拟字段中不存在模型Pin中的属性。这导致错误undefined method 'name' for #<Pin:0x41e0c08>

Answer 2

如果查看db / schema.rb，您会看到那里没有名称字段。

但如果你看一下app / models / pin.rb

class Pin < ActiveRecord::Base
     belongs_to :user
     has_attached_file :image, :styles => { :medium => "300x300>", :thumb => "100x100>" }


     validates :image, presence: true
     validates :description, presence: true
     validates :name, length: { minimum: 2 }
end

您将看到一个验证：name，您可能错误地将其添加到该文件而不是user.rb.您无法验证不存在的字段。

为什么创建引脚停止工作？

2 个答案: