BookListSerializer example for create case is still flawed #9469
Description
This example at https://www.django-rest-framework.org/api-guide/serializers/#customizing-multiple-update
class BookListSerializer(serializers.ListSerializer):
def update(self, instance, validated_data):
# Maps for id->instance and id->data item.
book_mapping = {book.id: book for book in instance}
data_mapping = {item['id']: item for item in validated_data}
# Perform creations and updates.
ret = []
for book_id, data in data_mapping.items():
book = book_mapping.get(book_id, None)
if book is None:
ret.append(self.child.create(data))
else:
ret.append(self.child.update(book, data))
The update method handles update/insertions/deletes. In the insertion case, because an id key value pair will not exist in validated data, so this line:
data_mapping = {item['id']: item for item in validated_data}
Will fail at item['id'], maybe it should be item.get('id'), but then maybe the rest of it might have to change too, e.g.:
for book_id, data in data_mapping.items():
if not book_id:
ret.append(self.child.create(data))
else:
object = object_mapping.get(book_id, None)
ret.append(self.child.update(object, data))