GET /subscriptions?expand: add customer expansion & JSON parsing

Author: yurii-prykhodko-solid

lib/src/expanded/subscription_expanded.dart

@@ -1,17 +1,22 @@
+import 'dart:convert';
+
 import 'package:stripe/messages.dart';
 import 'package:stripe/src/expanded.dart';
+import 'package:stripe/src/utils/expandable_fields/customer_expandable_field.dart';
 import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
 import 'package:stripe/src/utils/expandable_fields/latest_invoice_expanded_expandable_field.dart';
 
 class SubscriptionExpanded {
   final Subscription subscription;
   final List<Discount>? discounts;
   final InvoiceExpanded? latestInvoice;
+  final Customer? customer;
 
   SubscriptionExpanded({
     required this.subscription,
     this.discounts,
     this.latestInvoice,
+    this.customer,
   });
 
   factory SubscriptionExpanded.fromJson(
@@ -30,10 +35,20 @@ class SubscriptionExpanded {
       ).extract(json);
     }
 
+    Customer? customer;
+    if (expand.contains(SubscriptionExpandableField.customer)) {
+      const customerExpander = CustomerExpandableField();
+      customer = customerExpander.extract(json);
+
+      /// A shim so that Subscription gets parsed correctly
+      json[customerExpander.field] = customer.id;
+    }
+
     return SubscriptionExpanded(
       subscription: Subscription.fromJson(json),
       discounts: discounts,
       latestInvoice: latestInvoice,
+      customer: customer,
     );
   }
 }

lib/src/messages/enums/expandable_fields/subscription_expandable_field.dart

@@ -1,4 +1,5 @@
 enum SubscriptionExpandableField {
   discounts,
   latestInvoice,
+  customer,
 }

lib/src/resources/subscription.dart

@@ -3,6 +3,7 @@ import 'dart:async';
 import 'package:stripe/messages.dart';
 import 'package:stripe/src/expanded.dart';
 import 'package:stripe/src/utils/expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/customer_expandable_field.dart';
 import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
 import 'package:stripe/src/utils/expandable_fields/latest_invoice_expanded_expandable_field.dart';
 
@@ -62,6 +63,8 @@ class SubscriptionResource extends Resource<Subscription> {
         return LatestInvoiceExpandedExpandableField(
           expand: {InvoiceExpandableField.paymentIntent},
         );
+      case SubscriptionExpandableField.customer:
+        return CustomerExpandableField();
     }
   }
 

lib/src/utils/expandable_fields/customer_expandable_field.dart

@@ -0,0 +1,12 @@
+import 'package:stripe/messages.dart';
+import 'package:stripe/src/utils/expandable_field.dart';
+
+class CustomerExpandableField extends ExpandableField<Customer> {
+  @override
+  String get field => 'customer';
+
+  const CustomerExpandableField();
+
+  @override
+  Customer extract(Map<String, dynamic> json) => Customer.fromJson(json[field]);
+}