Rails 4使用 carrierwave 上传多个图像或文件

这是解决方案上传多个图像使用载波在轨道4从头开始

或者你可以找到工作演示: 多重连接 Rails 4

要做的只是遵循以下步骤。

rails new multiple_image_upload_carrierwave

在 gem 文件中

gem 'carrierwave'
bundle install
rails generate uploader Avatar

创建支撑脚手架

rails generate scaffold post title:string

创建 post _ attachold

rails generate scaffold post_attachment post_id:integer avatar:string


rake db:migrate

在后 rb

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

在 post _ atting.rb 中

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

在 post _ controller. rb 中

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/post/_ 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 %>

为任何文章编辑附件和附件列表。 在 views/post/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 %>

更新表单以编辑附件 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 _ attance _ 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中不需要定义强参数，因为您可以在模型中定义 Attribute _ access，并在 post 模型中接受 _ nested _ Attribute，因为在 Rails 4中不推荐使用 Attribute access。

对于编辑附件，我们不能一次修改所有的附件。因此，我们将一个接一个地替换附件，或者您可以根据您的规则进行修改，这里我只是向您展示如何更新任何附件。

使用关联 @post.post_attachments时，不需要设置 post_id。

此外，我想出了如何更新多个文件上传，我也重构了一点。这个密码是我的，但你明白我的意思。

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

下面是我对模型的第二个重构:

1. 将私有方法移动到建模。
2. 用 self 替换@主板。

总监:

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

主板型号:

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

如果我们看一下 CarrierWave 的文档，现在实际上非常简单。

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，作为一个示例。

1. 获取主分支 Carrierwave 并将其添加到 Gemfile:

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

2. Create a column in the intended model to host an array of images:

   rails generate migration AddPicturesToProducts pictures:json
   

3. Run the migration

   bundle exec rake db:migrate
   

4. Add pictures to model Product

   app/models/product.rb
   
   
   class Product < ActiveRecord::Base
   validates :name, presence: true
   mount_uploaders :pictures, PictureUploader
   end
   

5. Add pictures to strong params in ProductsController

   app/controllers/products_controller.rb
   
   
   def product_params
   params.require(:product).permit(:name, pictures: [])
   end
   

6. Allow your form to accept multiple pictures

   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 %>
   

7. In your views, you can reference the images parsing the pictures array:

   @product.pictures[1].url
   

If you choose several images from a folder, the order will be the exact order you are taking them from top to bottom.

对 战略科学军团答案的一些小小补充:

> 不需要您更改父对象的控制器

name: "post_attachments[avatar][]"

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

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

  <%= 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 %>

@post_attachment = @post.post_attachments.build

class Post < ApplicationRecord
...
accepts_nested_attributes_for :post_attachments, allow_destroy: true
end

 <% 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 %>

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