ruby on rails - How do i set a parent_id using s3_direct_upload gem? -

newbie on rails 3.2.14, testing on heroku, uploading image files s3 s3_direct_upload gem.

i've got gem working fine. drag , drop, progress bars , direct upload s3 work great. upload tied attachment model. new record created on upload. fine far.

the issue i'm having want set parent_id field of new record don't know how pass in. gem doesn't use conventional form submit upload, it's handled via javascript:

<%= s3_uploader_form callback_url: attachments_url, callback_param: "attachment[attachment_url]", id: "mys3uploader" %>     <%= file_field_tag :file, multiple: true %> <% end %> 

the create action in attachments_controller.rb:

def create   @attachment = attachment.create(params[:attachment]) end 

calls javascript view create.js.erb:

<% if @attachment.new_record? %>   alert("failed upload attachment: <%= j @attachment.errors.full_messages.join(', ').html_safe %>"); <% else %>   $("#attachments").prepend("<%= j render(@attachment) %>"); <% end %> 

which checks if record save worked , adds new upload thumbnail current view.

since i'm not dealing regular form or create action i'm bit stumped.

i can set default values in attachment model before_save:

before_save :set_defaults  def set_defaults   self.name = "photo"   self.parent_id = 1 end 

but parent_id defined on page uploads done, during creation of parent object (i.e. blog post).

i know should using has_many , belongs_to , they're set , working fine since i'm not using conventional form submit data don't know how assign parent_id.

i've tried passing parent_id in form , accessing in model:

<%= s3_uploader_form callback_url: attachments_url(:parent_id => 99), callback_param: "attachment[attachment_url]", id: "mys3uploader" %> 

it didn't work , know i'm not supposed accessing params inside model anyway.

any me past point appreciated.

ok, read lot of questions , answers on here , pieced myself.

so on right track passing in (:parent_id => 99) shouldn't have been trying use in model, should using in controller.

i changed create method in controller fetch draft parent object had created , make new attachment record child of it:

def create   @parent = parent.find(params[:parent_id])   @attachment = @parent.attachments.create(params[:attachment]) end 

the value of :parent_id passed in coming 'new' parent form (:parent_id => @parent.id).

it's working fine now. utter lack of experience holding me :)