accepts_nested_attributes_for with has_many polymorphic

Question

I use paperclip to upload multi-file attached to studentcourseassignment,but i fail.

model

class StudentCourseAssignment < ActiveRecord::Base
    attr_accessible :score, :comment, :finish_status,:attachments
    accepts_nested_attributes_for :attachments
    belongs_to :assignment
    belongs_to :user
    has_many :attachments ,:as => :attachmentable,:dependent => :destroy
end

class Attachment < ActiveRecord::Base
    attr_accessible :user_upload 
    belongs_to :attachmentable , :polymorphic => true
    has_attached_file :user_upload
end

controller

**new**

    @sca = StudentCourseAssignment.new 
    @sca.attachments.build
    @sca.attachments.build

**create**

    @sca = StudentCourseAssignment.new(params[:student_course_assignment])
    @assignment = Assignment.find(params[:assignment_id])
    @sca.user = current_user
    @sca.assignment = @assignment
    if @sca.save
        flash[:alert] = "success"
        redirect_to course_years_path
    else
        flash[:alert] = "fail"
        redirect_to course_years_path
    end

** view**

<%= form_for @sca, :url => assignment_student_course_assignments_path(@assignment),
:html => { :id => 'student-assignment-form', :multipart => true } do |f| %>
file:
<%= f.fields_for :attachments do |a_f| %>
<%= a_f.file_field :user_upload %>
<%= submit_tag "create" %>
<% end%>
<% end %>

wrong

No association found for name `attachments'. Has it been defined yet?

if remove accepts_nested_attributes_for :attachments，it's still wrong

Attachment(#70201401779680) expected, got Array(#70201383294620)

hope your help!thx!

John · Accepted Answer · 2013-01-10 16:46:47Z

2

Change

from:

attr_accessible :score, :comment, :finish_status,:attachments

to:

attr_accessible :score, :comment, :finish_status,:attachments_attributes

answered Jan 10, 2013 at 16:46

John

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Comments

BFGeorge9000 · Accepted Answer · 2014-07-21 05:10:35Z

1

I realize this is an old question, but fwiw I think you'll need to move

accepts_nested_attributes_for :attachments

to appear after

has_many :attachments, :as => :attachmentable,:dependent => :destroy

I hit this in a project once myself; pretty sure it boils down to accepts_nested_attributes_for expecting the relation to already be declared before its invoked.

answered Jul 21, 2014 at 5:10

BFGeorge9000

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