Custom validation, error message can't display - ruby-on-rails

Question

I have an order form where my users are suposed to validate the conditions of sales to proceed to payment.
If the user hasn't checked the box, I want him to be warned to do so..
I just don't manage to do that...
Update (add the shopping cart)
the order is initialzed in a shooping cart:
class ShoppingCart
delegate :sub_total, to: :order
def initialize(token:)
#token = token
end
def order
#order ||= Order.find_or_initialize_by(token: #token, status: 0) do |order|
order.sub_total = 0
end
end
end
the form in orders/new.html.erb
<%= simple_form_for #order, url: clients_checkout_path do |f| %>
<div class="<%= 'error_message' if #order.errors.full_messages.any? %> ">
<% if #order.errors.any? %>
<% #order.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
<% end %>
</div>
<%= f.hidden_field :user_id %>
<%= f.input :cgos_accepted, as: :boolean, checked_value: true, unchecked_value: false %>
<%= f.submit, class: "btn btn-main btn-block" %>
<% end %>
here is the controller:
class Clients::OrdersController < Clients::ApplicationController
def index
#orders = Order.all
#orders = #orders.filter_by_status(params[:status]) if params[:status]
end
def show
#order = Order.find(params[:id])
end
def new
#order = current_cart.order
#billing_address = BillingAddress.new
end
def create
#order = current_cart.order
#order.update_sub_total!
#order.update_total!
if #order.update_attributes!(order_params.merge(user_id: current_user.id))
redirect_to new_clients_order_payment_path(#order)
end
end
private
def order_params
params.require(:order).permit(:status, :user_id, :token , :sub_total, :cgos_accepted)
end
end
in my order model I added a validation:
class Order < ApplicationRecord
validate :accept_cgos, on: :update
#[...]
private
def accept_cgos
if self.cgos_accepted == false
errors.add(:base, :must_accept_cgos)
end
end
end
my yml file is:
en:
activerecord:
errors:
models:
order:
attributes:
base:
must_accept_cgos: Please accept the general condition of sales
I was expecting the warning message to be displayed in the div but it is opening Better Error and says:
ActiveRecord::RecordInvalid at /clients/cart/checkout
Validation failed: Please accept the general condition of sales
So it's kinda working but why isn't it displaying in my error div?

Answer 1

update_attributes!
You are using the bang-version of update_attributes, update_attributes!. Just like save! and create! it will throw an exception when saving is unsuccessful.
If you remove the exclamation mark in that method call, update_attributes will return false when being unable to save, instead.
Rendering the error
The other part that is missing is rendering the new template in case of a validation error. If update_attributes returns true, a redirect will take place, but if it returns false, rails will attempt to render create.html.erb by default. But the new template can be also used in this case but rails has to be told to do so.
Code changes
The changed implementation might then look like this.
if #order.update_attributes(order_params.merge(user_id: current_user.id)) # no bang
redirect_to new_clients_order_payment_path(#order)
else
#billing_address = BillingAddress.new # because the #new template requires it.
render :new
end

Answer 2

why isn't it displaying in my error div?
Because of your create action, you're doing the redirect_to, the redirect_to flush the order instance and all your errors from object is vanished, try to add render :new instead.
# for example
def create
if #order.updated
redirect_to path
else
render :new
end
end