FIX: Pricing table for one-off purchases (#228)

When using the Stripe Pricing table for one-off purchases
(non-subscriptions) the webhook was encountering an error because it was
expecting subscription information which does not exist for one-off
purchases. This fix addresses that issue ensuring that no errors occur,
that users are added to the appropriate group, and that uses can see
their purchase on the billing page.

app/controllers/discourse_subscriptions/hooks_controller.rb

@@ -44,23 +44,27 @@ module DiscourseSubscriptions
 
         discourse_customer = Customer.create(user_id: user.id, customer_id: customer_id)
 
-        Subscription.create(
-          customer_id: discourse_customer.id,
-          external_id: checkout_session[:subscription],
-        )
+        subscription = checkout_session[:subscription]
+
+        if !subscription.nil?
+          Subscription.create(customer_id: discourse_customer.id, external_id: subscription)
+        end
 
         line_items =
           ::Stripe::Checkout::Session.list_line_items(checkout_session[:id], { limit: 1 })
         item = line_items[:data].first
+
         group = plan_group(item[:price])
         group.add(user) unless group.nil?
         discourse_customer.product_id = item[:price][:product]
         discourse_customer.save!
 
-        ::Stripe::Subscription.update(
-          checkout_session[:subscription],
-          { metadata: { user_id: user.id, username: user.username } },
-        )
+        if !subscription.nil?
+          ::Stripe::Subscription.update(
+            subscription,
+            { metadata: { user_id: user.id, username: user.username } },
+          )
+        end
       when "customer.subscription.created"
       when "customer.subscription.updated"
         subscription = event[:data][:object]

app/controllers/discourse_subscriptions/user/payments_controller.rb

@@ -27,7 +27,12 @@ module DiscourseSubscriptions
               payments = ::Stripe::PaymentIntent.list(customer: customer_id)
               payments_from_invoices =
                 payments[:data].select { |payment| invoice_ids.include?(payment[:invoice]) }
-              data = data | payments_from_invoices
+
+              # Pricing table one-off purchases do not have invoices
+              payments_without_invoices =
+                payments[:data].select { |payment| payment[:invoice].nil? }
+
+              data = data | payments_from_invoices | payments_without_invoices
             end
           end
 
@@ -42,14 +47,13 @@ module DiscourseSubscriptions
       private
 
       def parse_invoices(all_invoices, product_ids)
-        invoices_with_products =
-          all_invoices[:data].select do |invoice|
-            invoice_lines = invoice[:lines][:data][0] if invoice[:lines] && invoice[:lines][:data]
-            if invoice_lines
-              invoice_product_id = parse_invoice_lines(invoice_lines)
-              product_ids.include?(invoice_product_id)
-            end
+        all_invoices[:data].select do |invoice|
+          invoice_lines = invoice[:lines][:data][0] if invoice[:lines] && invoice[:lines][:data]
+          if invoice_lines
+            invoice_product_id = parse_invoice_lines(invoice_lines)
+            product_ids.include?(invoice_product_id)
           end
+        end
       end
 
       def parse_invoice_lines(invoice_lines)

spec/requests/hooks_controller_spec.rb

@@ -83,6 +83,27 @@ RSpec.describe DiscourseSubscriptions::HooksController do
       }
     end
 
+    let(:checkout_session_completed_data_one_off) do
+      {
+        object: {
+          id: "cs_test_a1ENei5A9TGOaEketyV5qweiQR5CyJWHT5j8T3HheQY3uah3RxzKttVUKZ",
+          object: "checkout.session",
+          customer: customer.customer_id,
+          customer_email: user.email,
+          invoice: nil,
+          metadata: {
+          },
+          mode: "subscription",
+          payment_status: "paid",
+          status: "complete",
+          submit_type: nil,
+          subscription: nil,
+          success_url: "http://localhost:4200/my/billing/subscriptions",
+          url: nil,
+        },
+      }
+    end
+
     let(:checkout_session_completed_bad_data) do
       {
         object: {
@@ -184,6 +205,26 @@ RSpec.describe DiscourseSubscriptions::HooksController do
       end
     end
 
+    describe "checkout.session.completed for one-off purchase" do
+      before do
+        event = {
+          type: "checkout.session.completed",
+          data: checkout_session_completed_data_one_off,
+        }
+        ::Stripe::Checkout::Session
+          .stubs(:list_line_items)
+          .with(checkout_session_completed_data[:object][:id], { limit: 1 })
+          .returns(list_line_items_data)
+
+        ::Stripe::Webhook.stubs(:construct_event).returns(event)
+      end
+
+      it "is returns 200" do
+        expect { post "/s/hooks.json" }.to change { user.groups.count }.by(1)
+        expect(response.status).to eq 200
+      end
+    end
+
     describe "checkout.session.completed with anonymous user" do
       before do
         checkout_session_completed_bad_data[:object][:customer_email] = "anonymous@example.com"

spec/requests/user/payments_controller_spec.rb

@@ -60,5 +60,20 @@ RSpec.describe DiscourseSubscriptions::User::PaymentsController do
       expect(invoice).to eq("inv_900007")
       expect(parsed_body.count).to eq(2)
     end
+
+    it "gets pricing table one-off purchases" do
+      ::Stripe::Invoice.expects(:list).with(customer: "c_345678").returns(data: [])
+
+      ::Stripe::PaymentIntent
+        .expects(:list)
+        .with(customer: "c_345678")
+        .returns(data: [{ id: "pi_900010", invoice: nil, created: Time.now }])
+
+      get "/s/user/payments.json"
+
+      parsed_body = response.parsed_body
+
+      expect(parsed_body.count).to eq(1)
+    end
   end
 end