Implement a generic way of creating related resources, based on the t…

…ype attribute

appstoreconnect/api.py

@@ -84,9 +84,27 @@ def _get_resource(self, Resource, resource_id):
 		payload = self._api_call(url)
 		return Resource(payload.get('data', {}), self)
 
-	def _get_related_resource(self, Resource, full_url):
+	def _get_resource_from_payload_data(self, payload):
+		try:
+			resource_type = resources[payload.get('type')]
+		except KeyError:
+			raise APIError("Unsupported resource type %s" % resources[payload.get('type')])
+
+		return resource_type(payload, self)
+
+	def get_related_resource(self, full_url):
 		payload = self._api_call(full_url)
-		return Resource(payload.get('data', {}), self)
+		data = payload.get('data')
+		if data is None:
+			return None
+		elif type(data) == dict:
+			return self._get_resource_from_payload_data(data)
+
+	def get_related_resources(self, full_url):
+		payload = self._api_call(full_url)
+		data = payload.get('data', [])
+		for resource in data:
+			yield self._get_resource_from_payload_data(resource)
 
 	def _create_resource(self, Resource, args):
 		attributes = {}

appstoreconnect/resources.py

@@ -1,3 +1,4 @@
+import inspect
 from abc import ABC, abstractmethod
 import sys
 
@@ -12,22 +13,16 @@ def __getattr__(self, item):
 			return self._data.get('id')
 		if item in self._data.get('attributes', {}):
 			return self._data.get('attributes', {})[item]
-		if item in self._data.get('relationships', {}):
-			def callable():
+		if item in self.relationships:
+			def getter():
 				# Try to fetch relationship
 				nonlocal item
-				is_resources = item[-1] == 's'
-				try:
-					item_cls = getattr(sys.modules[__name__], item[0].upper() + (item[1:-1] if is_resources else item[1:]))
-				except AttributeError:
-					item_cls = Resource
 				url = self._data.get('relationships', {})[item]['links']['related']
-				# List of resources
-				if is_resources:
-					return self._api._get_resources(item_cls, full_url=url)
+				if self.relationships[item]['multiple']:
+					return self._api.get_related_resources(full_url=url)
 				else:
-					return self._api._get_related_resource(item_cls, full_url=url)
-			return callable
+					return self._api.get_related_resource(full_url=url)
+			return getter
 
 		raise AttributeError('%s have no attributes %s' % (self.type_name, item))
 
@@ -211,3 +206,10 @@ class FinanceReport(Resource):
 class SalesReport(Resource):
 	endpoint = '/v1/salesReports'
 	filters = 'https://developer.apple.com/documentation/appstoreconnectapi/download_sales_and_trends_reports'
+
+
+# create an index of Resources by type
+resources = {}
+for name, obj in inspect.getmembers(sys.modules[__name__]):
+	if inspect.isclass(obj) and issubclass(obj, Resource) and hasattr(obj, 'type') and obj != Resource:
+		resources[getattr(obj, 'type')] = obj