Rails, update the product right after create one - ruby-on-rails

Question

I have the web app on RoR, but the issue is once the user upload the image, the product_id is not associated with the product_attachments. Not until I proceed to next form.
Following were my controller
ProductAttachmentsController:
class ProductAttachmentsController < ApplicationController
before_action :set_product_attachment, only: [:show, :edit, :update, :destroy]
def index
#product_attachments = ProductAttachment.all
end
def show
end
def new
#product_attachment = ProductAttachment.new
end
def create
#product_attachment = ProductAttachment.new(product_attachment_params)
respond_to do |format|
if #product_attachment.save
format.html { redirect_to #product_attachment, notice: 'Product attachment was successfully created.' }
format.json {render :json => #product_attachment}
else
format.html { render :new }
format.json { render json: #product_attachment.errors, status: :unprocessable_entity }
end
end
end
def update
respond_to do |format|
if #product_attachment.update(product_attachment_params)
format.html { redirect_to #product_attachment.product, notice: 'Product attachment was successfully updated.' }
format.json { render :show, status: :ok, location: #product_attachment }
else
format.html { render :edit }
format.json { render json: #product_attachment.errors, status: :unprocessable_entity }
end
end
end
def destroy
#product_attachment.destroy
respond_to do |format|
format.html { redirect_to product_attachments_url, notice: 'Product attachment was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_product_attachment
#product_attachment = ProductAttachment.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def product_attachment_params
params.require(:product_attachment).permit(:product_id, :attachment)
end
end
How can I trick the create method, so it will create a product_id when I create product_attachment? Currently I need to proceed next step and it trigger update method to insert product_id in product_attachments table. Thanks!!

Answer 1

You can store the product attachment id in a session variable
if #product_attachment.save
session[:product_attachment] = #product_attachment.id ### HERE!
format.html { redirect_to #product_attachment, notice: 'Product attachment was successfully created.' }
format.json {render :json => #product_attachment}
else
format.html { render :new }
format.json { render json: #product_attachment.errors, status: :unprocessable_entity }
end
When you create the product (in the ProductsController ) recall the attachment and update the product_id
if #product.save
if session[:product_attachment]
ProductAttachment.find(session[:product_attachment]).update_attribute(:product_id, #product.id)
session[:product_attachment] = nil
end
...
end