ruby on rails about form_for

Question

Hi I want to create an ec site and try to make quantity system.

What I want to do: Adding a item in quantity of CreateBasketItems(2021_create_basket_items.rb)

Question: How can I write some code in item/show.html.erb which is part of form_with() in particular?

2021_create_basket_items.rb

class CreateBasketItems < ActiveRecord::Migration[5.2]
      def change
        create_table :basket_items do |t|
          t.references :basket, index: true, null: false, foreign_key: true
          t.references :item, index: true, null: false, foreign_key: true
          t.integer    :quantity, null: false, default: 1
          t.timestamps
        end
      end
    end

item/show.html.erb

The url:  show.html.erb => item_controller.rb/create

<%= form_for url: item_add_to_baskets_path(@item,@basket_item), method: :post do |f| %>
　　<%= f.select :quantity,[1,2,3], id: "country1", class: "frm-field required sect" %>
   <%= f.submit "add to basket", class: "item_add" %> 
<% end %>

just in case the error is.

ArgumentError (wrong number of arguments (given 1, expected 0)):

item_controller.rb

class ItemsController < ApplicationController
  # before_action :authenticate_user!
  def show
    basket = current_user.prepare_basket
    @item = Item.find(params[:id])
    @basket_item = basket.basket_items(params[:quantity])
  end
  
  def index
    # if(params[:category])
    #   @items = Item.where(category: params[:category]).paginate(page: params[:page])
    # else
    #   @items = Item.paginate(page: params[:page])
    # end
    @items = (params[:category]) ? Item.where(category: params[:category]).paginate(page: params[:page]) :
    Item.paginate(page: params[:page])
  end
end

add_to_basket_controller.rb

class Items::AddToBasketsController < Items::ApplicationController
  def create
    basket = current_user.prepare_basket
    @item = Item.find(params[:item_id])
    @basket_item = basket.basket_items(params[:quantity])
    basket.basket_items.create!(item_id: @item.id, quantity: @basket_item)
    flash[:success] = "your item in basket"
    redirect_to baskets_path
  end
end

Answer 1

There are a couple of issues with the code.

• basket.basket_items doesn't expect any arguments but you're passing one. In fact, you don't need that line of code at all. Remove it.

• You're not passing the right quantity to the create! call.

basket.basket_items.create!(item_id: @item.id, quantity: params[:quantity])