Rails 4 multiple image or file upload using carrierwave - ruby-on-rails-4

Question

How can I upload multiple images from a file selection window using Rails 4 and CarrierWave? I have a post_controller and post_attachments model. How can I do this?
Can someone provide an example? Is there a simple approach to this?

Answer 1

This is solution to upload multiple images using carrierwave in rails 4 from scratch
Or you can find working demo :
Multiple Attachment Rails 4
To do just follow these steps.
rails new multiple_image_upload_carrierwave
In gem file
gem 'carrierwave'
bundle install
rails generate uploader Avatar
Create post scaffold
rails generate scaffold post title:string
Create post_attachment scaffold
rails generate scaffold post_attachment post_id:integer avatar:string
rake db:migrate
In post.rb
class Post < ActiveRecord::Base
has_many :post_attachments
accepts_nested_attributes_for :post_attachments
end
In post_attachment.rb
class PostAttachment < ActiveRecord::Base
mount_uploader :avatar, AvatarUploader
belongs_to :post
end
In 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
In views/posts/_form.html.erb
<%= 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 %>
To edit an attachment and list of attachment for any post.
In views/posts/show.html.erb
<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 %>
Update form to edit an attachment 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 %>
Modify update method in post_attachment_controller.rb
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
In rails 3 no need to define strong parameters and as you can define attribute_accessible in both the model and accept_nested_attribute to post model because attribute accessible is deprecated in rails 4.
For edit an attachment we cant modify all the attachments at a time. so we will replace attachment one by one, or you can modify as per your rule, Here I just show you how to update any attachment.

Answer 2

If we take a look at CarrierWave's documentation, this is actually very easy now.
https://github.com/carrierwaveuploader/carrierwave/blob/master/README.md#multiple-file-uploads
I will use Product as the model I want to add the pictures, as an example.
Get the master branch Carrierwave and add it to your Gemfile:
gem 'carrierwave', github:'carrierwaveuploader/carrierwave'
Create a column in the intended model to host an array of images:
rails generate migration AddPicturesToProducts pictures:json
Run the migration
bundle exec rake db:migrate
Add pictures to model Product
app/models/product.rb
class Product < ActiveRecord::Base
validates :name, presence: true
mount_uploaders :pictures, PictureUploader
end
Add pictures to strong params in ProductsController
app/controllers/products_controller.rb
def product_params
params.require(:product).permit(:name, pictures: [])
end
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 %>
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.

Answer 3

Some minor additions to the SSR answer:
accepts_nested_attributes_for does not require you to change the parent object's controller. So if to correct
name: "post_attachments[avatar][]"
to
name: "post[post_attachments_attributes][][avatar]"
then all these controller changes like these become redundant:
params[:post_attachments]['avatar'].each do |a|
#post_attachment = #post.post_attachments.create!(:avatar => a)
end
Also you should add PostAttachment.new to the parent object form:
In views/posts/_form.html.erb
<%= 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 %>
This would make redundant this change in the parent's controller:
#post_attachment = #post.post_attachments.build
For more info see Rails fields_for form not showing up, nested form
If you use Rails 5, then change Rails.application.config.active_record.belongs_to_required_by_default value from true to false (in config/initializers/new_framework_defaults.rb) due to a bug inside accepts_nested_attributes_for (otherwise accepts_nested_attributes_for won't generally work under Rails 5).
EDIT 1:
To add about destroy:
In models/post.rb
class Post < ApplicationRecord
...
accepts_nested_attributes_for :post_attachments, allow_destroy: true
end
In views/posts/_form.html.erb
<% 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 %>
This way you simply do not need to have a child object's controller at all! I mean no any PostAttachmentsController is needed anymore. As for parent object's controller (PostController), you also almost don't change it - the only thing you change in there is the list of the whitelisted params (to include the child object-related params) like this:
def post_params
params.require(:post).permit(:title, :text,
post_attachments_attributes: ["avatar", "#original_filename", "#content_type", "#headers", "_destroy", "id"])
end
That's why the accepts_nested_attributes_for is so amazing.

Answer 4

Also I figured out how to update the multiple file upload and I also refactored it a bit. This code is mine but you get the drift.
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

Here is my second refactor into the model:
Move private methods to model.
Replace #motherboard with self.
Controller:
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
In motherboard model:
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

Answer 6

When using the association #post.post_attachments you do not need to set the post_id.