Rails活動記錄::沒有找到使用友好的ID和slu recognition識別

Question

我設置了我的Rails應用程序來使用friendly_id和paperclip，並且我已經使用遷移將slug列添加到'designs'數據庫表中。當我創建一個新的設計後，並上傳自己的形象（使用回形針）當我檢查數據庫，然後我得到一個有效記錄的錯誤，說下面沒有更新slug列：

這裏有我的代碼片段：

型號：

class Design < ApplicationRecord 
 
    attr_accessor :slug 
 
    extend FriendlyId 
 
    friendly_id :img_name, use: [:slugged, :finders] 
 
    has_attached_file :image, styles: { 
 
    :thumb => ['100x100#', :jpg, :quality => 70], 
 
    :preview => ['480>',  :jpg, :quality => 70], 
 
    :large => ['800>',  :jpg, :quality => 30], 
 
    :retina => ['1200>',  :jpg, :quality => 30] 
 
}, 
 
:convert_options => { 
 
    :thumb => '-set colorspace sRGB -strip', 
 
    :preview => '-set colorspace sRGB -strip', 
 
    :large => '-set colorspace sRGB -strip', 
 
    :retina => '-set colorspace sRGB -strip -sharpen 0x0.5' 
 
} 
 
    validates_attachment_content_type :image, content_type: /\Aimage\/.*\z/ 
 
end

控制器：

class DesignsController < ApplicationController 
 
    before_action :find_design, only: [:show, :edit, :update, :destroy] 
 
    before_action :authenticate_user!, except: [:index, :show] 
 

 
    def index 
 
    @designs = Design.all.order("created_at desc") 
 
    end 
 

 
    def new 
 
    @design = Design.new 
 
    end 
 

 
    def create 
 
    @design = Design.new(design_params) 
 

 
    if @design.save 
 
     redirect_to @design, notice: "Hellz yeah, Steve! Your artwork was successfully saved!" 
 
    else 
 
     render 'new', notice: "Oh no, Steve! I was unable to save your artwork!" 
 
    end 
 
    end 
 

 
    def show 
 
    end 
 

 
    def edit 
 
    end 
 

 
    def update 
 
    if @design.update design_params 
 
     redirect_to @design, notice: "Huzzah! Your artwork was successfully saved!" 
 
    else 
 
     render 'edit' 
 
    end 
 
    end 
 

 
    def destroy 
 
    @design.destroy 
 
    redirect_to designs_path 
 
    end 
 

 
    private 
 

 
    def design_params 
 
    params.require(:design).permit(:img_name, :slug, :image, :caption) 
 
    end 
 

 
    def find_design 
 
    @design = Design.friendly.find(params[:id]) 
 
    end 
 
end

視圖（#show）

<div id="post_show_content" class="skinny_wrapper wrapper_padding"> 
 
    <header> 
 
     <p class="date"><%= @design.created_at.strftime("%A, %b %d") %></p> 
 
     <h1><%= @design.img_name %></h1> 
 
     <hr> 
 
    </header> 
 
      <%= image_tag @design.image.url(:retina), class: "image" %> 
 
     <div class="caption"> 
 
      <p><%= @design.caption %></p> 
 
     </div> 
 

 
    <% if user_signed_in? %> 
 
     <div id="admin_links"> 
 
     <%= link_to "Edit Artwork", edit_design_path(@design) %> 
 
     <%= link_to "Delete Artwork", design_path(@design), method: :delete, data: {confirm: "Are you sure?" } %> 
 
     </div> 
 
    <% end %> 
 

 
    
 

 
</div>

遷移：

class AddSlugToDesigns < ActiveRecord::Migration[5.0] 
 
    def change 
 
    add_column :designs, :slug, :string 
 
    add_index :designs, :slug, unique: true 
 
    end 
 
end

Answer 1

ActiveRecord使用find_by方法找到塞模型。您find_design方法看起來像這樣

class DesignsController < ApplicationController 
    def find_design 
    @design = Design.find_by(slug: params[:id]) 
    end 
end 

在您的設計模型

您還沒有定義img_name（這是一個方法調用）你指的friendly_id :img_name, use: [:slugged, :finders] 以下內容添加到您的模型design.rb

def img_name 
    self.img_name 
end 

另一種方法是跳過使用friendly_id gem並編寫自己的方法來生成隨機slu and並將其稱爲before_validation。像

before_validation :set_slug, :on => :create 

def set_slug 
    random_token = SecureRandom.hex(3) 
    self.slug = "#{self.img_name.downcase}_#{random_token}" 
end 

然後使用您的控制器Design.find_by(slug: params[:id])，你需要用塞

Answer 2

運行rails generate friendly_id運行遷移之前，查詢數據庫。儘管之前我已經爲數據庫中的其他模型和表格完成了這個工作，但我仍需要在新表格中運行新slug的遷移之前再次執行此操作。