Using ng-file-upload with Rails carrierwave gem to upload multiple files

All we need is an easy explanation of the problem, so here it is.

I’m trying to combine ng-file-upload and carrierwave to upload multiple files, but the controller on server side receives only one file (the last item of the selected files).

Client side (reference)

html

<button type="file" ng-model="files" ngf-select ngf-multiple="true">Upload</button>

js

var upload = function (files, content) {
    return Upload.upload({
        url: 'MY_CONTROLLER_URL',
        file: files, // files is an array of multiple files
        fields: { 'MY_KEY': 'MY_CONTENT' }
    }).progress(function (evt) {
        var progressPercentage = parseInt(100.0 * evt.loaded / evt.total);
        console.log('progress: ' + progressPercentage + '% ' + evt.config.file.name);
    }).success(function (data, status, headers, config) {
        console.log('files ' + config.file.name + ' uploaded. Response: ' + data);
    }).error(function (data, status, headers, config) {
        console.log('error status: ' + status);
    });
};

console.log(files) prints Array[File, File, …] (Browser: FireFox). So on client side it does get the selected files. On the GitHub page of ng-file-upload says it supports array of files for html5.

Server side (reference)

posts_controller.rb

def create
    @post = Post.new(post_params)
    @post.attaches = params[:file]
    @post.save
    render json: @post
end

private
def post_params
    params.require(:post).permit(:content, :file)
end

where @post.attaches is the attachments of a post and params[:file] is sent from client side by file parameter in Upload.upload.

I want to store an array of files into @post.attaches, but params[:file] contains only one file of the selected files.
puts params[:file] prints:

#<ActionDispatch::Http::UploadedFile:0x007fddd1550300 @tempfile=#<Tempfile:/tmp/RackMultipart20150812-2754-vchvln.jpg>, @original_filename="Black-Metal-Gear-Rising-Wallpaper.jpg", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"file\"; filename=\"Black-Metal-Gear-Rising-Wallpaper.jpg\"\r\nContent-Type: image/jpeg\r\n">

This shows that there is only one file in params[:file]. I’m not sure if there is anything wrong with the usage of this parameter.

How could I solve this problem?

Here is my post.rb model and attach_uploader.rb (created by carrierwave) for reference if needed:

post.rb

class Post < ActiveRecord::Base
    mount_uploaders :attaches, AttachUploader
end

attach_uploader.rb

class AttachUploader < CarrierWave::Uploader::Base
    storage :file
    def store_dir
        "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
    end
end

and @post.attaches column in database posts is added by

rails g migration add_attaches_to_posts attaches:json

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

I finally found a way to solve my problem. Thanks for carrierwave and danialfarid‘s awesome ng-file-upload.

My problem was I couldn’t send all selected files. My solution was

var upload = function (files) {
    var names = [];
    for (var i = 0; i < files.length; ++i)
        names.push(files[i].name);
    return Upload.upload({
        url: '/api/v1/posts',
        file: files,
        fileFormDataName: names
    });
}

Then in my rails controller.rb

file_arr = params.values.find_all { |value| value.class == ActionDispatch::Http::UploadedFile }

if @post.save
  unless file_arr.empty?
    file_arr.each { |attach|
      @attach = Attach.new
      @attach.filename = attach
      @attach.attachable = @post
      @attach.save
    }
  end
  render json: @post
end

I created an array to store all my files from params.

I tried to use a column with mount_uploaders of carrierwave to store an array of files, but it didn’t work. So I create a file table called attaches to store my files

class CreateAttaches < ActiveRecord::Migration
  def change
    create_table :attaches do |t|
      t.string :filename
      t.references :attachable, polymorphic: true
      t.timestamps null: false
    end
  end
end

where attachable is used to store the post id and type. (Here my attachments belong to some post in my forum.)

Here is some details about setting if needed

attach.rb (model)

class Attach < ActiveRecord::Base
  mount_uploader :filename, AttachUploader
  belongs_to :attachable, :polymorphic => true
end

post.rb (model)

class Post < ActiveRecord::Base
  has_many :attaches, as: :attachable, dependent: :destroy
end

post_serializer.rb

class PostSerializer < ActiveModel::Serializer
  has_many :attaches
end

attach_serializer.rb

class AttachSerializer < ActiveModel::Serializer
  attributes :url, :name

  def url
    object.filename.url
  end

  def name
    object.filename_identifier
  end
end

Then in html file can have a row code

<div ng-repeat="attach in post.attaches">
    <img ng-src="{{attach.url}}" type="file" height="180" width="320" accept="image/*"/>
    <a target="_self" ng-show="attach.url" href="{{attach.url}}" rel="nofollow noreferrer noopener" download="{{attach.name}}">{{attach.name}}<p></p></a>
</div>

where my default attachments are used for images.

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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