Uploading multiple images using paperclip

Question

I am new to Ruby on Rails. I am trying to upload multiple images using paperclip. I have three model * Award * Album * Photo

I have the following mappings

In model Award i have

has_one :album

In the model Album i have

has_many :photos
belongs_to :award

In the model photo i have

belongs_to :album

so when i create a new award, it will have an album, and the album will have many photos. I am using paperclip in model photo.

so when i create a new award how will i link the album and photo, and how i am suppose to save the photos. How to handle multiple image uploading using paperclip in this case?

Award model

---

class Award < ActiveRecord::Base
  attr_accessible :album_id, :award_title, :description, :receiving_date

  #mappings 
  has_one     :album 

  #validate presence of fields
  validates_presence_of :album_id,:title,:description,:receiving_date

  #validate that description has minimum length 3
  validates_length_of :description, :minimum => 3

  #validates that title has length >=3
  validates_length_of :title, :minimum => 3

end

Album model

---

class Album < ActiveRecord::Base
  attr_accessible :description, :title, :award_id

  #mappings 
  has_many    :photos
  belongs_to  :award  

  #validate presence of fields
  validates_presence_of :award_id,:title,:description

  #validate that title has minimum length 3
  validates_length_of :title, :minimum => 3

  #validate that description has minimum length 10
  validates_length_of :description, :minimum => 10

end

Photo model

---

class Photo < ActiveRecord::Base
  attr_accessible :album_id, :image_url

   #mappings 
  belongs_to  :album

  #validate presence of fields
  validates_presence_of :album_id,:image_url

end

Answer 1

You may wish to look at the has_many :through relationship - which means you use one model (album in your case) as a join model , which will have two foreign keys - photo_id and award_id

Here's what I'd do:

#app/models/album.rb
Class Album < ActiveRecord::Base
    belongs_to :photo, :class_name => 'Photo'
    belongs_to :award, :class_name => 'Award'
    accepts_nested_attributes_for :photo
end

#app/models/award.rb
Class Award < ActiveRecord::Base
    has_many :albums, :class_name => 'Album'
    has_many :photos, :class_name => 'Photo', :through => :albums
    accepts_nested_attributes_for :albums
end

#app/models/photo.rb
Class Photo < ActiveRecord::Base
    has_many :albums, :class_name => 'Album'
    has_many :awards, :class_name => 'Award', :through => :albums
end

This will mean that you'll be able to call @award.photos -- it will show you all the photos which are contained in the albums assigned to the award

To upload multiple images to this, you'd be able to use accepts_nested_attributes_for like this:

#app/controllers/awards_controller.rb
def new
    @award = Award.new
    @award.albums.build.build_photo
end

def create
    @award = Award.new(award_params)
    @award.save
end

private
def award_params
    params.require(:award).permit(:award, :variables, albums_attributes: [:extra, :vars, photo_attributes: [:photo]])
end

You could then add this to your upload form:

<%= form_for @award do |f| %>
    <%= f.text_field :your_vars %>
    <%= f.fields_for :albums do |a| %>
        <%= a.text_field :extra_var %>
        <%= a.fields_for :photo do |p| %>
             <%= p.file_field :photo %>
        <% end %>
    <% end %>
<% end %>