Avoiding fields_for for adding a single record to associated model

Question

I have the following associations:

class Developer < ActiveRecord::Base
  has_many :large_photos, :class_name => 'Photo', :conditions => { :large => true }, :reject_if => proc { |x| x['image'].blank? }
end

class Photo < ActiveRecord::Base
  belongs_to :developer
  mount_uploader :image, ImageUploader # Carrierwave
end

Now, I'm looking to build a Development form which, when submitted, will add a single file field for uploading a new Photo. At the moment I have:

<%= form_for @developer do |form| %>

    <%= form.fields_for :large_photos do |sf| %>
    <div class="dropzone">
        <%= sf.file_field :image %>
        <%= sf.hidden_field :large, :value => '1' %>
        <%= sf.hidden_field :image_cache %>
    </div>
    <% end %>

<% end%>

Now, the problem I have with this is that fields_for is looping through the existing records (of course it is!) which I'd prefer to avoid, I just want to add a single file field for uploading a new photo. How would I go about this?

Answer 1

<%= form.fields_for :large_photos, @developer.large_photos.build do |project_fields| %>

Instead of creating the fields for each existing photos, this line builds a new Photo and show the fields only for this one (so the fields are empty, I think it's what you want).