Rails: Polymorphic assosiation and accepts_nested_attributes - ruby-on-rails

Question

The attachment won't save. What I am missing here?
In my application I have a project ,for each project user can upload many assets. The Upload is done by carrier wave.
here are the models
class Project < ActiveRecord::Base
has_many :assets,:as => :assetable,dependent: :destroy
accepts_nested_attributes_for :assets, :allow_destroy => true
end
class Asset < ActiveRecord::Base
belongs_to :project
belongs_to :user
belongs_to :assetable, :polymorphic => true
mount_uploader :attachment, AttachmentUploader #carrierwave
validates :attachment, presence: true
validates :project_id, presence: true
end
and these are the actions in my project_controller
def new
#project = Project.new
#asset = #project.assets.build
end
def create
#project = Project.new(project_params)
#project.assets.build
respond_to do |format|
if #project.save
format.html { redirect_to #project, notice: 'Project was successfully created.' }
format.json { render :show, status: :created, location: #project }
else
format.html { render :new }
format.json { render json: #project.errors, status: :unprocessable_entity }
end
end
def project_params
params.require(:project).permit(:user_id, :summary, :start_date,assets_attributes: [:id, :project_id, :attachment,:user_id] )
end
this is how the form looks like
<%= form_for #project,:html => {:multipart => true } do |f| %>
<% if #project.errors.any? %>
<div id="error_explanation">
</div>
<% end %>
<%= f.fields_for :assets do |p| %>
<div class="field">
<%= p.label :attachment %><br>
<%= p.file_field :attachment,name: "assets[attachment][]" %>
</div>
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>

Answer 1

schema.rb
create_table "assets", force: true do |t|
t.string "assetable_id"
t.string "assetable_type"
t.string "attachment"
t.datetime "created_at"
t.datetime "updated_at"
end
create_table "projects", force: true do |t|
t.string "user_id"
t.string "summary"
t.datetime "created_at"
t.datetime "updated_at"
end
projects/_form.html.erb
<%= form_for #project, :html => {:multipart => true } do |f| %>
<% if #project.errors.any? %>
<div id="error_explanation">
<%= #project.errors.inspect %>
</div>
<% end %>
<%= f.label :summary %>
<%= f.text_field :summary %>
<%= f.fields_for :assets do |p| %>
<div class="field">
<%= p.label :attachment %><br>
<%= p.file_field :attachment %>
<%= p.hidden_field :assetable_id %>
<%= p.hidden_field :assetable_type %>
</div>
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
projects_controller.rb
# GET /projects/new
def new
#project = Project.new
#project.assets.build
end
# POST /projects
# POST /projects.json
def create
#project = Project.new(project_params)
respond_to do |format|
if #project.save
format.html { redirect_to #project, notice: 'Project was successfully created.' }
format.json { render :show, status: :created, location: #project }
else
format.html { render :new }
format.json { render json: #project.errors, status: :unprocessable_entity }
end
end
end
private
# Never trust parameters from the scary internet, only allow the white list through.
def project_params
params.require(:project).permit(:user_id, :summary, :start_date, assets_attributes: [:id, :assetable_id, :assetable_type, :attachment, :user_id] )
end
project.rb
class Project < ActiveRecord::Base
has_many :assets, :as => :assetable, dependent: :destroy
accepts_nested_attributes_for :assets, :allow_destroy => true
end
asset.rb
class Asset < ActiveRecord::Base
belongs_to :project
belongs_to :assetable, :polymorphic => true
mount_uploader :attachment, AttachmentUploader #carrierwave
validates :attachment, presence: true
validates :assetable_type, presence: true
end
Aside
Since you based this question off a previous question you asked I'll just mention: You only want to use a polymorphic association if you intend instances of your asset class to belong to different types of classes (ie. things other than a project).