Step.10 寫一支機器人塞亂數產品進去 - Azraeil/JCcart_Note GitHub Wiki

裝新的gem faker

add gem "faker" to Gemfile，然後bundle install再重開rails s。

接著我們去faker GitHub，這是一個塞假資料的gem，JC後來是使用Faker::Address.state

先進入console

rails c

:001 > Faker
:002 > Item.count
:003 > Item
:004 > 100.times do |i|
:005 >     Item.create(:name => Faker::Address.state, :price => rand(1..3000))
:006?>   end;
:007 >   true

然後發現噴了，查看錯誤訊息，是因為少了default的cate_id

ActiveRecord::StatementInvalid: Mysql2::Error: Field 'cate_id' doesn't have a default value:
            INSERT INTO `items` (`name`, `price`, `created_at`, `updated_at`)
            VALUES ('Virginia', 2474, '2016-09-09 08:45:00', '2016-09-09 08:45:00')

所以我們再繼續

:008 >   100.times do |i|
:009 >     Item.create(:name => Faker::Address.state, :price => rand(1..3000), :cate => cate)
:010?>   end; true

就能成功生假資料，接著再去重整localhost:3000/dashboard/admin/items就能看到100筆資料，然後我們隨便拿一筆資料按編輯，然後發現他又噴Template is missing

fix admin/items_controller

fix app/controllers/dashboard/admin/items_controller.rb

class Dashboard::Admin::ItemsController < Dashboard::Admin::AdminController
  def index
    @items = @paginate = Item.order('id DESC').paginate(:page => params[:page])
  end

  def new
    @item = Item.new
  end

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

  def create
    @item = Item.new(item_params)
    @item.save
    redirect_to action: :index #這是舊版寫法
    #新版寫法  redirect_to dashboard_admin_items_path
  end

  def update
    @item.update(item_params)
    redirect_to action: :index
  end

  def destroy
    @item.destroy
    redirect_to action: :index
  end
end

private

def item_params
  params.require(:item).permit!
end

通常後台會倒序排序，所以會寫Item.order('id DESC').paginate(:page => params[:page])

接著再按編輯，發現又噴了，查看錯誤訊息，是先前index.html.erb的route寫錯

fix admin/items/index.html.erb

fix app/views/dashboard/admin/items/index.html.erb

原本是

<%= link_to '編輯', edit_item_path(item) %>

查看route，應該是要走到dashboard/admin/items#edit，查看Prifx應該是edit_dashboard_admin_item，所以我們改成

<%= link_to '編輯', edit_dashboard_admin_item_path(item) %>

delete原本的路由也是錯的，改成

<%= link_to '刪除', dashboard_admin_item_path(item), method: :delete, data: { confirm: '你確定嗎?' } %>

fix admin/items/edit.html.erb

重整頁面再按一次編輯，然後又噴了，錯誤訊息是寫form_for有問題，所以辜狗去查rails api form_for

這邊都會把form_for怎麼用講得很清楚，我們去看form_for傳的url參數，發現是傳:url，所以我們回去改

fix app/views/dashboard/admin/items/edit.html.erb

<%= form_for @item, :url => dashboard_admin_item_path, method: :patch  do |f| %>
  ...
  ...
<% end %>

接著再重整頁面，然後按編輯，終於能work了

fix dashboard/admin/items_controller

接著，我們隨便找一個來編輯，改掉價格後送出，又噴undefined method "update" for nil:NilClass，是因為我們在controller的upeate action沒有宣告@item

fix app/controllers/dashboard/admin/items_controller.rb

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

眼角餘光掃到destroy action也沒有，一樣加上@item = Item.find(params[:id])

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