Build API URLs to work with any FDC Shopify shop

We can extend this service class when there are other APIs. And
hopefully the DFC will provide a standard for this discovery at some
point.

app/jobs/backorder_job.rb

@@ -1,10 +1,6 @@
 # frozen_string_literal: true
 
 class BackorderJob < ApplicationJob
-  FDC_BASE_URL =  "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod"
-  FDC_CATALOG_URL = "#{FDC_BASE_URL}/SuppliedProducts".freeze
-  FDC_ORDERS_URL = "#{FDC_BASE_URL}/Orders".freeze
-
   # In the current FDC project, one shop wants to review and adjust orders
   # before finalising. They also run a market stall and need to adjust stock
   # levels after the market. This should be done within four hours.
@@ -36,9 +32,14 @@ class BackorderJob < ApplicationJob
 
   def self.place_backorder(order, linked_variants)
     user = order.distributor.owner
-    orderer = FdcBackorderer.new(user)
+
+    # We are assuming that all variants are linked to the same wholesale
+    # shop and its catalog:
+    urls = FdcUrlBuilder.new(linked_variants[0].semantic_links[0].semantic_id)
+    orderer = FdcBackorderer.new(user, urls)
+
     backorder = orderer.find_or_build_order(order)
-    broker = load_broker(order.distributor.owner)
+    broker = load_broker(order.distributor.owner, urls)
     ordered_quantities = {}
 
     linked_variants.each do |variant|
@@ -73,13 +74,13 @@ class BackorderJob < ApplicationJob
     retail_quantity
   end
 
-  def self.load_broker(user)
-    FdcOfferBroker.new(load_catalog(user))
+  def self.load_broker(user, urls)
+    FdcOfferBroker.new(load_catalog(user, urls))
   end
 
-  def self.load_catalog(user)
+  def self.load_catalog(user, urls)
     api = DfcRequest.new(user)
-    catalog_json = api.call(FDC_CATALOG_URL)
+    catalog_json = api.call(urls.catalog_url)
     DfcIo.import(catalog_json)
   end
 

app/jobs/complete_backorder_job.rb

@@ -16,13 +16,13 @@ class CompleteBackorderJob < ApplicationJob
   #             Having the id makes sure that we don't accidentally finalise
   #             someone else's order.
   def perform(user, distributor, order_cycle, order_id)
-    service = FdcBackorderer.new(user)
-    order = service.find_order(order_id)
+    order = FdcBackorderer.new(user, nil).find_order(order_id)
+    urls = FdcUrlBuilder.new(order.lines[0].offer.offeredItem.semanticId)
 
     variants = order_cycle.variants_distributed_by(distributor)
-    adjust_quantities(user, order, variants)
+    adjust_quantities(user, order, urls, variants)
 
-    service.complete_order(order)
+    FdcBackorderer.new(user, urls).complete_order(order)
   end
 
   # Check if we have enough stock to reduce the backorder.
@@ -30,8 +30,8 @@ class CompleteBackorderJob < ApplicationJob
   # Our local stock can increase when users cancel their orders.
   # But stock levels could also have been adjusted manually. So we review all
   # quantities before finalising the order.
-  def adjust_quantities(user, order, variants)
-    broker = FdcOfferBroker.new(BackorderJob.load_catalog(user))
+  def adjust_quantities(user, order, urls, variants)
+    broker = FdcOfferBroker.new(BackorderJob.load_catalog(user, urls))
 
     order.lines.each do |line|
       line.quantity = line.quantity.to_i

app/services/fdc_backorderer.rb

@@ -2,14 +2,11 @@
 
 # Place and update orders based on missing stock.
 class FdcBackorderer
-  FDC_BASE_URL = "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod"
-  FDC_ORDERS_URL = "#{FDC_BASE_URL}/Orders".freeze
-  FDC_SALE_SESSION_URL = "#{FDC_BASE_URL}/SalesSession/#".freeze
+  attr_reader :user, :urls
 
-  attr_reader :user
-
-  def initialize(user)
+  def initialize(user, urls)
     @user = user
+    @urls = urls
   end
 
   def find_or_build_order(ofn_order)
@@ -17,13 +14,13 @@ class FdcBackorderer
   end
 
   def build_new_order(ofn_order)
-    OrderBuilder.new_order(ofn_order, FDC_ORDERS_URL).tap do |order|
+    OrderBuilder.new_order(ofn_order, urls.orders_url).tap do |order|
       order.saleSession = build_sale_session(ofn_order)
     end
   end
 
   def find_open_order
-    graph = import(FDC_ORDERS_URL)
+    graph = import(urls.orders_url)
     open_orders = graph&.select do |o|
       o.semanticType == "dfc-b:Order" && o.orderStatus[:path] == "Held"
     end
@@ -125,12 +122,12 @@ class FdcBackorderer
   end
 
   def new?(order)
-    order.semanticId == FDC_ORDERS_URL
+    order.semanticId == urls.orders_url
   end
 
   def build_sale_session(order)
     SaleSessionBuilder.build(order.order_cycle).tap do |session|
-      session.semanticId = FDC_SALE_SESSION_URL
+      session.semanticId = urls.sale_session_url
     end
   end
 end

app/services/fdc_url_builder.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+# The DFC standard doesn't include endpoint discovery yet.
+# So for now we are guessing URLs based on our FDC pilot project.
+class FdcUrlBuilder
+  attr_reader :catalog_url, :orders_url, :sale_session_url
+
+  # At the moment, we start with a product link like this:
+  #
+  # https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/SuppliedProducts/44519466467635
+  def initialize(semantic_id)
+    @catalog_url, _slash, _id = semantic_id.rpartition("/")
+    @orders_url = @catalog_url.sub("/SuppliedProducts", "/Orders")
+    @sale_session_url = @catalog_url.sub("/SuppliedProducts", "/SalesSession/#")
+  end
+end

spec/jobs/backorder_job_spec.rb

@@ -57,7 +57,8 @@ RSpec.describe BackorderJob do
       )
       completion_time = Date.tomorrow.noon + 4.hours
 
-      orderer = FdcBackorderer.new(user)
+      urls = FdcUrlBuilder.new(product_link)
+      orderer = FdcBackorderer.new(user, urls)
       backorder = orderer.build_new_order(order)
       backorder.client = "https://openfoodnetwork.org.uk/api/dfc/enterprises/203468"
 

spec/jobs/complete_backorder_job_spec.rb

@@ -4,7 +4,11 @@ require 'spec_helper'
 
 RSpec.describe CompleteBackorderJob do
   let(:user) { build(:testdfc_user) }
-  let(:catalog) { BackorderJob.load_catalog(user) }
+  let(:catalog) { BackorderJob.load_catalog(user, urls) }
+  let(:urls) { FdcUrlBuilder.new(product_link) }
+  let(:product_link) {
+    "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/SuppliedProducts/44519466467635"
+  }
   let(:retail_product) {
     catalog.find { |item| item.semanticType == "dfc-b:SuppliedProduct" }
   }
@@ -12,7 +16,7 @@ RSpec.describe CompleteBackorderJob do
     flow = catalog.find { |item| item.semanticType == "dfc-b:AsPlannedProductionFlow" }
     catalog.find { |item| item.semanticId == flow.product }
   }
-  let(:orderer) { FdcBackorderer.new(user) }
+  let(:orderer) { FdcBackorderer.new(user, urls) }
   let(:order) {
     backorder = orderer.find_or_build_order(ofn_order)
     broker = FdcOfferBroker.new(catalog)

spec/services/fdc_backorderer_spec.rb

@@ -3,7 +3,11 @@
 require 'spec_helper'
 
 RSpec.describe FdcBackorderer do
-  let(:subject) { FdcBackorderer.new(order.distributor.owner) }
+  let(:subject) { FdcBackorderer.new(order.distributor.owner, urls) }
+  let(:urls) { FdcUrlBuilder.new(product_link) }
+  let(:product_link) {
+    "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/SuppliedProducts/44519466467635"
+  }
   let(:order) { create(:completed_order_with_totals) }
   let(:account) {
     OidcAccount.new(
@@ -25,11 +29,11 @@ RSpec.describe FdcBackorderer do
     # Build a new order when no open one is found:
     order.order_cycle = build(:order_cycle)
     backorder = subject.find_or_build_order(order)
-    expect(backorder.semanticId).to eq FdcBackorderer::FDC_ORDERS_URL
+    expect(backorder.semanticId).to eq urls.orders_url
     expect(backorder.lines).to eq []
 
     # Add items and place the new order:
-    catalog = BackorderJob.load_catalog(order.distributor.owner)
+    catalog = BackorderJob.load_catalog(order.distributor.owner, urls)
     product = catalog.find { |i| i.semanticType == "dfc-b:SuppliedProduct" }
     offer = FdcOfferBroker.new(nil).offer_of(product)
     line = subject.find_or_build_order_line(backorder, offer)
@@ -55,19 +59,19 @@ RSpec.describe FdcBackorderer do
   describe "#find_or_build_order" do
     it "builds an order object" do
       account.updated_at = Time.zone.now
-      stub_request(:get, FdcBackorderer::FDC_ORDERS_URL)
+      stub_request(:get, urls.orders_url)
         .to_return(status: 200, body: "{}")
 
       backorder = subject.find_or_build_order(order)
 
-      expect(backorder.semanticId).to eq FdcBackorderer::FDC_ORDERS_URL
+      expect(backorder.semanticId).to eq urls.orders_url
       expect(backorder.lines).to eq []
     end
   end
 
   describe "#find_or_build_order_line" do
     it "add quantity to an existing line item", vcr: true do
-      catalog = BackorderJob.load_catalog(order.distributor.owner)
+      catalog = BackorderJob.load_catalog(order.distributor.owner, urls)
       backorder = subject.find_or_build_order(order)
       existing_line = backorder.lines[0]
 

spec/services/fdc_offer_broker_spec.rb

@@ -4,7 +4,11 @@ require 'spec_helper'
 
 RSpec.describe FdcOfferBroker do
   subject { FdcOfferBroker.new(catalog) }
-  let(:catalog) { BackorderJob.load_catalog(user) }
+  let(:catalog) { BackorderJob.load_catalog(user, urls) }
+  let(:urls) { FdcUrlBuilder.new(product_link) }
+  let(:product_link) {
+    "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/SuppliedProducts/44519466467635"
+  }
   let(:user) { build(:testdfc_user) }
   let(:product) {
     catalog.find { |item| item.semanticType == "dfc-b:SuppliedProduct" }

spec/services/fdc_url_builder_spec.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe FdcUrlBuilder do
+  subject(:urls) { FdcUrlBuilder.new(product_link) }
+  let(:product_link) {
+    "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/SuppliedProducts/44519466467635"
+  }
+
+  it "knows the right URLs" do
+    expect(subject.catalog_url).to eq "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/SuppliedProducts"
+    expect(subject.orders_url).to eq "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/Orders"
+    expect(subject.sale_session_url).to eq "https://env-0105831.jcloud-ver-jpe.ik-server.com/api/dfc/Enterprises/test-hodmedod/SalesSession/#"
+  end
+end