Question

如何使用Rails 4和CarrierWave从文件选择窗口上传多个图像？我有post_controller和post_attachments模型。我怎么能这样做？

有人能提供一个例子吗？有一个简单的方法吗？

Answer 1

这是从头开始在rails 4中使用carrierwave上传多个图像的解决方案

或者你可以找到工作演示：   Multiple Attachment Rails 4

要执行以下步骤。

rails new multiple_image_upload_carrierwave

在宝石文件中

gem 'carrierwave' bundle install rails generate uploader Avatar

创建帖子支架

rails generate scaffold post title:string

创建post_attachment scaffold

rails generate scaffold post_attachment post_id:integer avatar:string rake db:migrate

在post.rb

class Post < ActiveRecord::Base has_many :post_attachments accepts_nested_attributes_for :post_attachments end

在post_attachment.rb

class PostAttachment < ActiveRecord::Base mount_uploader :avatar, AvatarUploader belongs_to :post end

在post_controller.rb

def show @post_attachments = @post.post_attachments.all end def new @post = Post.new @post_attachment = @post.post_attachments.build end def create @post = Post.new(post_params) respond_to do |format| if @post.save params[:post_attachments]['avatar'].each do |a| @post_attachment = @post.post_attachments.create!(:avatar => a) end format.html { redirect_to @post, notice: 'Post was successfully created.' } else format.html { render action: 'new' } end end end private def post_params params.require(:post).permit(:title, post_attachments_attributes: [:id, :post_id, :avatar]) end

在views / posts / _form.html.erb
中
<%= form_for(@post, :html => { :multipart => true }) do |f| %> <div class="field"> <%= f.label :title %><br> <%= f.text_field :title %> </div> <%= f.fields_for :post_attachments do |p| %> <div class="field"> <%= p.label :avatar %><br> <%= p.file_field :avatar, :multiple => true, name: "post_attachments[avatar][]" %> </div> <% end %> <div class="actions"> <%= f.submit %> </div> <% end %>

编辑任何帖子的附件和附件列表。 在views / posts / show.html.erb
中
<p id="notice"><%= notice %></p> <p> <strong>Title:</strong> <%= @post.title %> </p> <% @post_attachments.each do |p| %> <%= image_tag p.avatar_url %> <%= link_to "Edit Attachment", edit_post_attachment_path(p) %> <% end %> <%= link_to 'Edit', edit_post_path(@post) %> | <%= link_to 'Back', posts_path %>

更新表单以修改附件 views / post_attachments / _form.html.erb

<%= image_tag @post_attachment.avatar %> <%= form_for(@post_attachment) do |f| %> <div class="field"> <%= f.label :avatar %><br> <%= f.file_field :avatar %> </div> <div class="actions"> <%= f.submit %> </div> <% end %>

修改 post_attachment_controller.rb
中的更新方法
def update respond_to do |format| if @post_attachment.update(post_attachment_params) format.html { redirect_to @post_attachment.post, notice: 'Post attachment was successfully updated.' } end end end

在rails 3中，无需定义强参数，因为您可以在模型和accept_nested_attribute中定义attribute_accessible以发布模型，因为在rails 4中不推荐使用可访问属性。

要编辑附件，我们无法一次修改所有附件。所以我们将逐个替换附件，或者您可以根据您的规则进行修改，我只是告诉您如何更新任何附件。

Answer 2

如果我们看一下CarrierWave的文档，这实际上非常简单。

https://github.com/carrierwaveuploader/carrierwave/blob/master/README.md#multiple-file-uploads

我将使用Product作为我想添加图片的模型，作为一个例子。

获取主分支Carrierwave并将其添加到您的Gemfile：

gem 'carrierwave', github:'carrierwaveuploader/carrierwave'

在目标模型中创建一个列来托管图像数组：

rails generate migration AddPicturesToProducts pictures:json

运行迁移
```
bundle exec rake db:migrate
```

将图片添加到型号产品

app/models/product.rb

class Product < ActiveRecord::Base
  validates :name, presence: true
  mount_uploaders :pictures, PictureUploader
end

将图片添加到ProductsController中的强参数

app/controllers/products_controller.rb

def product_params
  params.require(:product).permit(:name, pictures: [])
end

允许您的表单接受多张图片

app/views/products/new.html.erb

# notice 'html: { multipart: true }'
<%= form_for @product, html: { multipart: true } do |f| %>
  <%= f.label :name %>
  <%= f.text_field :name %>

  # notice 'multiple: true'
  <%= f.label :pictures %>
  <%= f.file_field :pictures, multiple: true, accept: "image/jpeg, image/jpg, image/gif, image/png" %>

  <%= f.submit "Submit" %>
<% end %>

在您的视图中，您可以引用解析图片数组的图像：
```
@product.pictures[1].url
```

如果您从文件夹中选择多个图像，则订单将是您从上到下的确切顺序。

Answer 3

SSR 答案的一些小补充：

accepts_nested_attributes_for 不要求您更改父对象的控制器。所以如果要纠正

name: "post_attachments[avatar][]"

到

name: "post[post_attachments_attributes][][avatar]"

然后所有这些控制器的变化都变得多余了：

params[:post_attachments]['avatar'].each do |a|
  @post_attachment = @post.post_attachments.create!(:avatar => a)
end

此外，您应该将PostAttachment.new添加到父对象表单：

在views / posts / _form.html.erb

中

  <%= f.fields_for :post_attachments, PostAttachment.new do |ff| %>
    <div class="field">
      <%= ff.label :avatar %><br>
      <%= ff.file_field :avatar, :multiple => true, name: "post[post_attachments_attributes][][avatar]" %>
    </div>
  <% end %>

这会使父控制器中的这一变化多余：

@post_attachment = @post.post_attachments.build

有关详细信息，请参阅Rails fields_for form not showing up, nested form

如果你使用Rails 5，那么由于 accepts_nested_attributes_for Rails.application.config.active_record.belongs_to_required_by_default值从true更改为false（在config / initializers / new_framework_defaults.rb中） strong>（否则 accepts_nested_attributes_for 通常不会在Rails 5下运行。）

编辑1：

添加销毁：

在models / post.rb
中
class Post < ApplicationRecord ... accepts_nested_attributes_for :post_attachments, allow_destroy: true end

在views / posts / _form.html.erb
中
<% f.object.post_attachments.each do |post_attachment| %> <% if post_attachment.id %> <% post_attachments_delete_params = { post: { post_attachments_attributes: { id: post_attachment.id, _destroy: true } } } %> <%= link_to "Delete", post_path(f.object.id, post_attachments_delete_params), method: :patch, data: { confirm: 'Are you sure?' } %> <br><br> <% end %> <% end %>

这样你只需不需要就可以拥有一个子对象的控制器！我的意思是不再需要PostAttachmentsController了。至于父对象的控制器（PostController），你也几乎不改变它 - 你唯一改变的是白名单参数列表（包括子对象 - 相关的params）像这样：

def post_params params.require(:post).permit(:title, :text, post_attachments_attributes: ["avatar", "@original_filename", "@content_type", "@headers", "_destroy", "id"]) end

这就是为什么accepts_nested_attributes_for如此惊人。

Answer 4

另外我想出了如何更新多文件上传，我也稍微重构了一下。这段代码是我的，但你得到了漂移。

def create
  @motherboard = Motherboard.new(motherboard_params)
  if @motherboard.save
    save_attachments if params[:motherboard_attachments]
    redirect_to @motherboard, notice: 'Motherboard was successfully created.'
  else
    render :new
  end
end


def update
  update_attachments if params[:motherboard_attachments]
  if @motherboard.update(motherboard_params)
    redirect_to @motherboard, notice: 'Motherboard was successfully updated.'
  else
   render :edit
  end
end

private
def save_attachments
  params[:motherboard_attachments]['photo'].each do |photo|
    @motherboard_attachment = @motherboard.motherboard_attachments.create!(:photo => photo)
  end
end

 def update_attachments
   @motherboard.motherboard_attachments.each(&:destroy) if @motherboard.motherboard_attachments.present?
   params[:motherboard_attachments]['photo'].each do |photo|
     @motherboard_attachment = @motherboard.motherboard_attachments.create!(:photo => photo)
   end
 end

Answer 5

使用关联@post.post_attachments时，您无需设置post_id。

Answer 6

这是我对模型的第二个重构：

将私有方法移至模型。
将@motherboard替换为self。

控制器：

def create
  @motherboard = Motherboard.new(motherboard_params)

  if @motherboard.save
    @motherboard.save_attachments(params) if params[:motherboard_attachments]
  redirect_to @motherboard, notice: 'Motherboard was successfully created.'
  else
    render :new
  end
end

def update
  @motherboard.update_attachments(params) if params[:motherboard_attachments]
  if @motherboard.update(motherboard_params)
    redirect_to @motherboard, notice: 'Motherboard was successfully updated.'
  else
    render :edit
  end
end

在主板型号中：

def save_attachments(params)
  params[:motherboard_attachments]['photo'].each do |photo|
    self.motherboard_attachments.create!(:photo => photo)
  end
end

def update_attachments(params)
  self.motherboard_attachments.each(&:destroy) if self.motherboard_attachments.present?
  params[:motherboard_attachments]['photo'].each do |photo|
    self.motherboard_attachments.create!(:photo => photo)
  end
end

Rails 4使用carrierwave进行多个图像或文件上传

6 个答案: