extracted a new OrderHeader read model - Orders was responsible for the whole site and grew huge

Author: andrzejkrzywda

apps/rails_application/Makefile

@@ -22,6 +22,10 @@ mutate-orders: ## Run mutation tests for Orders namespace
 	@echo "Running mutation tests for Orders..."
 	@RAILS_ENV=test bundle exec mutant run "Orders*"
 
+mutate-order-header: ## Run mutation tests for OrderHeader namespace
+	@echo "Running mutation tests for OrderHeader..."
+	@RAILS_ENV=test bundle exec mutant run "OrderHeader*"
+
 mutate-client-orders: ## Run mutation tests for ClientOrders namespace
 	@echo "Running mutation tests for ClientOrders..."
 	@RAILS_ENV=test bundle exec mutant run "ClientOrders*"
@@ -101,5 +105,5 @@ test-mutant-runner:
 	@bin/rails tailwindcss:build
 	@RAILS_ENV=test bundle exec mutant test -j 4
 
-.PHONY: help install dev test mutate mutate-changes mutate-processes mutate-orders mutate-client-orders mutate-invoices mutate-shipments mutate-vat-rates mutate-coupons mutate-products mutate-public-offer mutate-customers mutate-admin mutate-time-promotions mutate-returns mutate-availability mutate-client-inbox mutate-authorization mutate-client-authentication css web test-mutant-runner
+.PHONY: help install dev test mutate mutate-changes mutate-processes mutate-orders mutate-order-header mutate-client-orders mutate-invoices mutate-shipments mutate-vat-rates mutate-coupons mutate-products mutate-public-offer mutate-customers mutate-admin mutate-time-promotions mutate-returns mutate-availability mutate-client-inbox mutate-authorization mutate-client-authentication css web test-mutant-runner
 .DEFAULT_GOAL := help

apps/rails_application/app/controllers/orders_controller.rb

@@ -4,12 +4,10 @@ def index
   end
 
   def show
+    @order_header = OrderHeader.find_by_uid(params[:id])
     @order = Orders.find_order(params[:id])
 
-    return not_found unless @order
-
-    @shipment = Shipments::Shipment.find_by(order_uid: @order.uid)
-    @invoice = Invoices::Invoice.find_or_initialize_by(order_uid: @order.uid)
+    return not_found unless @order_header && @order
   end
 
   def new

apps/rails_application/app/read_models/order_header/configuration.rb

@@ -0,0 +1,107 @@
+module OrderHeader
+  class Header < ApplicationRecord
+    self.table_name = "order_headers"
+  end
+
+  private_constant :Header
+
+  class Customer < ApplicationRecord
+    self.table_name = "orders_customers"
+  end
+
+  private_constant :Customer
+
+  def self.find_by_uid(uid)
+    Header.find_by_uid(uid)
+  end
+
+  class Configuration
+    def call(event_store)
+      event_store.subscribe(
+        ->(event) { draft_order_header(event) },
+        to: [Pricing::OfferDrafted]
+      )
+      event_store.subscribe(
+        ->(event) { assign_customer(event) },
+        to: [Crm::CustomerAssignedToOrder]
+      )
+      event_store.subscribe(
+        ->(event) { submit_order(event) },
+        to: [Fulfillment::OrderRegistered]
+      )
+      event_store.subscribe(
+        ->(event) { update_state(event, "Paid") },
+        to: [Fulfillment::OrderConfirmed]
+      )
+      event_store.subscribe(
+        ->(event) { update_state(event, "Cancelled") },
+        to: [Fulfillment::OrderCancelled]
+      )
+      event_store.subscribe(
+        ->(event) { update_state(event, "Expired") },
+        to: [Pricing::OfferExpired]
+      )
+      event_store.subscribe(
+        ->(event) { set_shipping_address(event) },
+        to: [Shipping::ShippingAddressAddedToShipment]
+      )
+      event_store.subscribe(
+        ->(event) { set_billing_address(event) },
+        to: [Invoicing::BillingAddressSet]
+      )
+      event_store.subscribe(
+        ->(event) { issue_invoice(event) },
+        to: [Invoicing::InvoiceIssued]
+      )
+    end
+
+    private
+
+    def find_or_create_header(order_id)
+      Header.find_or_create_by!(uid: order_id) { |header| header.state = "Draft" }
+    end
+
+    def draft_order_header(event)
+      Header.create!(
+        uid: event.data.fetch(:order_id),
+        state: "Draft"
+      )
+    end
+
+    def assign_customer(event)
+      customer_id = event.data.fetch(:customer_id)
+      customer_name = Customer.find_by_uid(customer_id).name
+      find_or_create_header(event.data.fetch(:order_id)).update!(customer: customer_name)
+    end
+
+    def submit_order(event)
+      find_or_create_header(event.data.fetch(:order_id)).update!(
+        number: event.data.fetch(:order_number),
+        state: "Submitted"
+      )
+    end
+
+    def update_state(event, state)
+      find_or_create_header(event.data.fetch(:order_id)).update!(state: state)
+    end
+
+    def set_shipping_address(event)
+      find_or_create_header(event.data.fetch(:order_id)).update!(
+        shipping_address_present: true
+      )
+    end
+
+    def set_billing_address(event)
+      find_or_create_header(event.data.fetch(:invoice_id)).update!(
+        billing_address_present: true
+      )
+    end
+
+    def issue_invoice(event)
+      find_or_create_header(event.data.fetch(:invoice_id)).update!(
+        invoice_issued: true,
+        invoice_number: event.data.fetch(:invoice_number)
+      )
+    end
+  end
+end

apps/rails_application/app/views/orders/show.html.erb

@@ -1,73 +1,73 @@
 <% content_for(:header) do %>
-  Order <%= @order.number %>
+  Order <%= @order_header.number %>
 <% end %>
-<%= turbo_stream_from "orders_order_#{@order.uid}" %>
+<%= turbo_stream_from "orders_order_#{@order_header.uid}" %>
 <% content_for(:actions) do %>
   <%= secondary_action_button do %>
-    <%= order_history_link(@order.uid) %>
+    <%= order_history_link(@order_header.uid) %>
   <% end %>
 
   <%= secondary_action_button do %>
-    <%= link_to "Invoice", invoice_path(@order.uid) %>
-  <% end if @invoice.issued? %>
+    <%= link_to "Invoice", invoice_path(@order_header.uid) %>
+  <% end if @order_header.invoice_issued? %>
 
   <%= secondary_action_button do %>
     <%= link_to 'Back', orders_path %>
   <% end %>
 
   <%= primary_action_button do %>
-    <%= link_to 'Edit', edit_order_path(@order.uid) %>
-  <% end if @order.state == "Draft" %>
+    <%= link_to 'Edit', edit_order_path(@order_header.uid) %>
+  <% end if @order_header.state == "Draft" %>
 
-  <% if @order.state == "Submitted" %>
-    <%= button_to("Pay", pay_order_path(@order.uid), class: "mr-3 ml-3 inline-flex items-center px-4 py-2 border rounded-md shadow-sm text-sm font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 border-transparent text-white bg-blue-600 hover:bg-blue-700") %>
+  <% if @order_header.state == "Submitted" %>
+    <%= button_to("Pay", pay_order_path(@order_header.uid), class: "mr-3 ml-3 inline-flex items-center px-4 py-2 border rounded-md shadow-sm text-sm font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 border-transparent text-white bg-blue-600 hover:bg-blue-700") %>
   <% end %>
 
-  <% if @order.state == "Paid" %>
-    <%= button_to("Return", order_returns_path(order_id: @order.uid), class: "ml-3 inline-flex items-center px-4 py-2 border rounded-md shadow-sm text-sm font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-50 border-gray-300 text-gray-700 bg-white hover:bg-gray-50") %>
+  <% if @order_header.state == "Paid" %>
+    <%= button_to("Return", order_returns_path(order_id: @order_header.uid), class: "ml-3 inline-flex items-center px-4 py-2 border rounded-md shadow-sm text-sm font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-50 border-gray-300 text-gray-700 bg-white hover:bg-gray-50") %>
   <% end %>
 
-  <% if (@order.state == "Submitted") %>
-    <%= button_to("Cancel Order", cancel_order_path(@order.uid), class: "inline-flex items-center px-4 py-2 border rounded-md shadow-sm text-sm font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-50 border-gray-300 text-gray-700 bg-white hover:bg-gray-50") %>
+  <% if @order_header.state == "Submitted" %>
+    <%= button_to("Cancel Order", cancel_order_path(@order_header.uid), class: "inline-flex items-center px-4 py-2 border rounded-md shadow-sm text-sm font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-50 border-gray-300 text-gray-700 bg-white hover:bg-gray-50") %>
   <% end %>
 <% end %>
 
 <dl class="mb-8">
   <dt class="font-bold">Customer</dt>
-  <dd class="mb-2"><%= @order.customer || "None" %></dd>
+  <dd class="mb-2"><%= @order_header.customer || "None" %></dd>
   <dt class="font-bold">State</dt>
-  <dd class="mb-2" id="<%= "orders_order_#{@order.uid}_state" %>"><%= @order.state %></dd>
+  <dd class="mb-2" id="<%= "orders_order_#{@order_header.uid}_state" %>"><%= @order_header.state %></dd>
   <dt class="font-bold">Shipping Details</dt>
   <dd class="mb-2">
-    <% unless @shipment&.full_address.present? %>
+    <% unless @order_header.shipping_address_present? %>
       Shipping address is missing.
     <% end %>
   </dd>
   <dd class="mb-2">
-    <% unless @shipment&.full_address.present? %>
+    <% unless @order_header.shipping_address_present? %>
       <%= link_to "Add shipment address",
-                  edit_order_shipping_address_path(@order.uid),
+                  edit_order_shipping_address_path(@order_header.uid),
                   class: 'px-2 py-1 border rounded-md shadow-sm text-xs font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 border-transparent text-white bg-blue-600 hover:bg-blue-700'
       %>
     <% else %>
       Your shipment has been queued for processing.
     <% end %>
   </dd>
-  <% if @order.state != "Draft" %>
+  <% if @order_header.state != "Draft" %>
     <dt class="font-bold">Billing Details</dt>
     <dd class="mb-2">
-      <% if @invoice.issued? %>
-        <%= link_to @invoice.number, invoice_path(@order.uid) %>
-      <% elsif !@invoice.address_present? %>
+      <% if @order_header.invoice_issued? %>
+        <%= link_to @order_header.invoice_number, invoice_path(@order_header.uid) %>
+      <% elsif !@order_header.billing_address_present? %>
         Billing address is missing.
         <%= link_to "Add billing address",
-                    edit_order_billing_address_path(@order.uid),
+                    edit_order_billing_address_path(@order_header.uid),
                     class: 'px-2 py-1 border rounded-md shadow-sm text-xs font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 border-transparent text-white bg-blue-600 hover:bg-blue-700'
         %>
       <% else %>
         Invoice not issued
         <%= button_to "Issue now",
-                    order_invoice_path(@order.uid),
+                    order_invoice_path(@order_header.uid),
                     class: 'px-2 py-1 border rounded-md shadow-sm text-xs font-medium focus:outline-none focus:ring-2 focus:ring-offset-2 focus:ring-blue-500 border-transparent text-white bg-blue-600 hover:bg-blue-700'
         %>
       <% end %>

apps/rails_application/db/migrate/20251229222553_create_order_headers.rb

@@ -0,0 +1,16 @@
+class CreateOrderHeaders < ActiveRecord::Migration[8.0]
+  def change
+    create_table :order_headers do |t|
+      t.uuid :uid, null: false, index: { unique: true }
+      t.string :number
+      t.string :customer
+      t.string :state, null: false
+      t.boolean :shipping_address_present, default: false
+      t.boolean :billing_address_present, default: false
+      t.boolean :invoice_issued, default: false
+      t.string :invoice_number
+
+      t.timestamps
+    end
+  end
+end

apps/rails_application/db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_12_24_213558) do
+ActiveRecord::Schema[8.0].define(version: 2025_12_29_231410) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_catalog.plpgsql"
   enable_extension "pgcrypto"
@@ -173,6 +173,20 @@
     t.boolean "submitted", default: false
   end
 
+  create_table "order_headers", force: :cascade do |t|
+    t.uuid "uid", null: false
+    t.string "number"
+    t.string "customer"
+    t.string "state", null: false
+    t.boolean "shipping_address_present", default: false
+    t.boolean "billing_address_present", default: false
+    t.boolean "invoice_issued", default: false
+    t.string "invoice_number"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["uid"], name: "index_order_headers_on_uid", unique: true
+  end
+
   create_table "order_lines", force: :cascade do |t|
     t.uuid "order_uid", null: false
     t.string "product_name"

apps/rails_application/lib/configuration.rb

@@ -6,6 +6,7 @@ def call(event_store, command_bus)
     enable_res_infra_event_linking(event_store)
 
     enable_orders_read_model(event_store)
+    enable_order_header_read_model(event_store)
     enable_products_read_model(event_store)
     enable_public_offer_products_read_model(event_store)
     enable_customers_read_model(event_store)
@@ -54,6 +55,10 @@ def enable_orders_read_model(event_store)
     Orders::Configuration.new.call(event_store)
   end
 
+  def enable_order_header_read_model(event_store)
+    OrderHeader::Configuration.new.call(event_store)
+  end
+
   def enable_invoices_read_model(event_store)
     Invoices::Configuration.new.call(event_store)
   end