Question

I think everything is fine.. but it doesn’t work..
I uploaded whole files on github
https://github.com/iom00/action2.git
I recently updated gem. But it has same problem on rails 3.2..
Plz help me~!

portfolio model

class Portf
  include Mongoid::Document
  field :title, type: String
  field :decs, type: String  

  attr_accessible :images
  embeds_many :images
  accepts_nested_attributes_for :images, :allow_destroy => true

end

image model

class Image
  include Mongoid::Document
  include Mongoid::Paperclip

  field :portf_id, type: Integer
  embedded_in :portf , :inverse_of => :images
  has_mongoid_attached_file :file
end

portfolio controller

  # GET /portfs/new
  # GET /portfs/new.json
  def new
    @portf = Portf.new
    5.times { @portf.images.build }

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @portf }
    end
  end

  # GET /portfs/1/edit
  def edit
    @portf = Portf.find(params[:id])
    5.times { @portf.images.build }
  end

form

  <%= form_for @portf, :html => { :multipart => true } do |f| %>
    <%= f.fields_for :images do |image| %>
             <% if image.object.new_record? %>
                   <%= image.file_field :file %>                                  
             <% end %>
   <% end %>

Answer 1

First of all, you need to make the images_attributes available for mass assignment instead of images therefore you have to do

  attr_accessible :images_attributes

You may also want to add :title there as well.

Furthermore, when you have paperclip attachments in embedded documents you need to add cascade callback. From https://github.com/meskyanichi/mongoid-paperclip :

Note on embedded documents: if you plan to save or update the parent document, you MUST add cascade_callbacks: true to your embeds_XXX statement. Otherwise, your data will be updated but the paperclip functions will not run to copy/update your file.

So you need to do:

  embeds_many :images, :cascade_callbacks => true

You can read more on cascading callbacks here: http://mongoid.org/en/mongoid/docs/relations.html#common

Also – there is a blocker issue with mongoid-paperclip right now https://github.com/meskyanichi/mongoid-paperclip/issues/32 the pull request is there but it has not been merged yet. So you may stumble upon this error if you use it with Mongoid 3.