多张图片上传错误

Question

我是新手 rails 4 我想添加多个 images.i 在我的产品模型和图片模型中 app.product 有很多图片并且图片有图像及其回形针附件但我无法在我的视图中访问图像 models/products.rb

class Product < ActiveRecord::Base
belongs_to :user
belongs_to :category
has_many :comments , dependent: :destroy
has_many :pictures, :dependent => :destroy
end

models/picture.rb

class Picture < ActiveRecord::Base
belongs_to :product
accepts_nested_attributes_for :images,:allow_destroy => true
has_attached_file :image,:styles => {
:thumb    => ['100x100#',  :jpg, :quality => 70],
:preview  => ['480x480#',  :jpg, :quality => 70],
:large    => ['600>',      :jpg, :quality => 70],
:retina   => ['1200>',     :jpg, :quality => 30]
},
:path => ":rails_root/public/images/:id/:filename",
:url  => "/images/:id/:filename"

do_not_validate_attachment_file_type :image
end

查看页面

<div class="row">
                <% @products.each do |product| %>
                <div class="col-sm-3  col-lg-3 col-md-3">
                    <div class="thumbnail">

                        <%= product.image.url(:thumb) %>
                        <div class="caption">
                            <h4 class="pull-right">Rs.<%= product.price %>   </h4>
                            <h4><%= link_to 'Show', product %>
                            </h4>
                            <p><strong>Name:</strong>&emsp;  <%= product.name %></span></p>
                            <% if !product.description.blank? %>
                                <p><strong>Description:</strong> <%= product.description %></p>
                            <% end %>
                            <% if !product.reason.blank? %>
                                <p><strong>Reason:</strong><%= product.reason %></p>
                            <% end %>

                        </div>

                    </div>
                </div>
                <% end %>
</div>

Answer 1

请试试这个：

<% for asset in @picture.assets %>
 <%= link_to image_tag(asset.image.url(:thumb)), asset.image.url(:original) %>
<% end %>

希望对您有所帮助。您也可以关注下方link:

https://github.com/Emerson/Multiple-File-Uploads-with-Paperclip-and-Rails-3/blob/master/app/views/posts/show.html.erb

Answer 2

您正试图在父模型上调用嵌套方法。

你有：

#app/models/product.rb
class Product < ActiveRecord::Base
   has_many :pictures
end

#app/models/picture.rb
class Picture < ActiveRecord::Base
   belongs_to :product
   has_attached_file :image
end

这意味着您必须致电：

<% @products.each do |product| %>
   <% product.pictures.each do |picture| %>
      <%= picture.image.url %>
   <% end %>
<% end %>

--

您收到 noMethod 错误，因为您试图在 Product 对象（不存在）上调用 image：

<%= picture.image.url #-> doesn't exist %>

修复

修复比您意识到的要复杂一些。

具体来说，您必须确保能够 add/create 来自 accepts_nested_attributes_for 方法的嵌套 Picture 对象：

#app/models/product.rb
class Product < ActiveRecord::Base
   has_many :pictures
   accepts_nested_attributes_for :pictures 
end

这将允许您创建适当的表单和控制器操作：

#app/controllers/products_controller.rb
class ProductsController < ApplicationController
   def new
      @product = Product.new
      @product.pictures.build
   end

   def create
      @product = Product.new product_params
      @product.save
   end

   private

   def product_params
      params.require(:product).permit(..., pictures_attributes: [:image])
   end
end

然后您将使用 fields_for:

#app/views/products/new.html.erb
<%= form_for @product do |f| %>
   <%= f.fields_for :pictures do |p| %>
     <%= p.file_field :image %>
   <% end %>
   <%= f.submit %>
<% end %>

这将允许您使用新产品保存新的 Picture/images，然后使用上面的代码，您将能够展示它们！！

奖金

我一直分享的一个专业提示是 paperclip_defaults:

#config/application.rb
...
config.paperclip_defaults = {
   :styles => {
       :thumb    => ['100x100#',  :jpg, :quality => 70],
       :preview  => ['480x480#',  :jpg, :quality => 70],
       :large    => ['600>',      :jpg, :quality => 70],
       :retina   => ['1200>',     :jpg, :quality => 30] #-> is this correct formatting?
   },
   :path => ":rails_root/public/images/:id/:filename",
   :url  => "/images/:id/:filename"
}

您可以在 config/application.rb 中将它们设置为 "defaults"，而不是在您的 Picture 模型中包含所有样式 - 这样您就可以调用 has_attached_file :image ，根据需要更改样式：

#app/models/picture.rb
class Picture < ActiveRecord::Base
   has_attached_file :image #-> will use the defaults which can be overridden as required
end

多张图片上传错误

error with multiple image upload

ruby-on-rails

paperclip