Question

我正在制作一个小型应用程序，需要能够将图像上传到帖子/广告然后显示该图像。

我正在使用'Paperclip' gem来处理图片上传。每当我创建帖子/广告时，都会显示默认的“missing.jpg”，而不是我的图片。

广告控制器

class AdsController < ApplicationController
  before_action :set_ad, only: [:show, :edit, :update, :destroy]
  before_action :authenticate_user!

  # GET /ads
  # GET /ads.json
  def index
    @ads = Ad.all
  end

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

  # GET /ads/new
  def new
    @ad = Ad.new
  end

  # GET /ads/1/edit
  def edit
  end

  # POST /ads
  # POST /ads.json
  def create
    @ad = Ad.new(ad_params)

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

  # PATCH/PUT /ads/1
  # PATCH/PUT /ads/1.json
  def update
    respond_to do |format|
      if @ad.update(ad_params)
        format.html { redirect_to @ad, notice: 'Ad was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: 'edit' }
        format.json { render json: @ad.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /ads/1
  # DELETE /ads/1.json
  def destroy
    @ad.destroy
    respond_to do |format|
      format.html { redirect_to ads_url }
      format.json { head :no_content }
    end
  end

  private
    # Use callbacks to share common setup or constraints between actions.
    def set_ad
      @ad = Ad.find(params[:id])
    end

    # Never trust parameters from the scary internet, only allow the white list through.
    def ad_params
      params.require(:ad).permit(:title, :url, images_attributes: [:preview])
    end
end

广告_形式视图

<style type="text/css">
.header {
  display: none!important;
}
</style>

<%= form_for @ad, :html => {:multipart => true} do |f| %>
  <% if @ad.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@ad.errors.count, "error") %> prohibited this ad from being saved:</h2>

      <ul>
      <% @ad.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :title %><br>
    <%= f.text_field :title %>
  </div>
  <div class="field">
    <span>Contact (URL, Mobile, Address)</span><br>
    <%= f.text_field :url %>
  </div>
  <div class="field">
    <%= f.label :image %><br>
    <%= f.file_field :preview %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

广告模型

class Ad < ActiveRecord::Base

    attr_accessible :title, :url, :preview
    belongs_to :user
  has_attached_file :preview, :default_url => "missing.jpg"

  validates :title, length: { maximum: 20 }
  validates :url, length: { maximum: 20 }
end

广告索引视图

<h1>Listing ads</h1>




    <% @ads.each do |ad| %>
    <div class="adspace_grid">
      <%= image_tag ad.preview.url %>
      <div class="text_info">
      <span class="bold"><%= ad.title %></span> / 
      <span class="bold">Contact : </span><%= ad.url %>
      </div>
    </div> 
    <%= link_to 'Delete', ad, :method => :delete %> 
    <% end %>


<br>

<%= link_to 'New Ad', new_ad_path %>

非常感谢任何帮助。感谢

编辑：这是Google Chrome控制台中的错误。 Error Code

Answer 1

问题在于您允许ad属性：

# Never trust parameters from the scary internet, only allow the white list through.
def ad_params
  params.require(:ad).permit(:title, :url, images_attributes: [:preview])
end

我不确定你为什么在这里images_attributes: [:preview]。方法定义应该只是：

def ad_params
  params.require(:ad).permit(:title, :url, :preview)
end

您没有收到上传图片并获得默认missing.jpg的原因是因为您未在:preview ad_params {{}}}中url创建了您在表单中选择的图片文件1}}方法。

<强>更新

就路径而言，您应该能够将path和has_attached_file等其他参数提供给# app/models/ad.rb has_attached_file :preview, :default_url => "missing.jpg", :url => "/assets/ads/preview/:id/:style/:basename.:extension", :path => ":rails_root/public/assets/preview/:id/:style/:basename.:extension"。如下所示：

public/assets/ads/preview/:id/:style/

使用此功能，您上传的所有预览文件都将位于{{1}}目录中。

Rails Paperclip - 无法正确上传图像

1 个答案: