Initial extensions to automatically handle foreign keys in reverse ma…

…ppings

oscar_odin/mappings/_model_mapper.py

@@ -0,0 +1,69 @@
+"""Extended model mapper for Django models."""
+from typing import Sequence
+
+from django.db.models import ManyToManyRel, ManyToOneRel, OneToOneRel
+from odin.mapping import MappingBase, MappingMeta
+from odin.utils import getmeta
+
+
+class ModelMappingMeta(MappingMeta):
+    """Extended type of mapping meta."""
+
+    def __new__(cls, name, bases, attrs):
+        mapping_type = super().__new__(cls, name, bases, attrs)
+
+        if mapping_type.to_obj is None:
+            return mapping_type
+
+        # Extract out foreign field types.
+        mapping_type.one_to_one_fields = one_to_one_fields = []
+        mapping_type.many_to_one_fields = many_to_one_fields = []
+        mapping_type.many_to_many_fields = many_to_many_fields = []
+        for relation in getmeta(mapping_type.to_obj).related_objects:
+            if isinstance(relation, OneToOneRel):
+                one_to_one_fields.append(relation.related_name)
+            elif isinstance(relation, ManyToOneRel):
+                many_to_one_fields.append(relation.related_name)
+            elif isinstance(relation, ManyToManyRel):
+                many_to_many_fields.append(relation.related_name)
+
+        return mapping_type
+
+
+class ModelMapping(MappingBase, metaclass=ModelMappingMeta):
+    """Definition of a mapping between two Objects."""
+
+    exclude_fields = []
+    mappings = []
+    one_to_one_fields: Sequence[str] = []
+    many_to_one_fields: Sequence[str] = []
+    many_to_many_fields: Sequence[str] = []
+
+    def create_object(self, **field_values):
+        """Create a new product model."""
+
+        [
+            (name, field_values.pop(name))
+            for name in self.one_to_one_fields
+            if name in field_values
+        ]
+        many_to_one_values = [
+            (name, field_values.pop(name))
+            for name in self.many_to_one_fields
+            if name in field_values
+        ]
+        [
+            (name, field_values.pop(name))
+            for name in self.many_to_many_fields
+            if name in field_values
+        ]
+
+        obj = super().create_object(**field_values)
+
+        # TODO add one_to_one_values
+        for name, value in many_to_one_values:
+            if value:
+                getattr(obj, name).set(value)
+        # TODO add many_to_many_values
+
+        return obj

oscar_odin/mappings/catalogue.py

@@ -4,6 +4,7 @@
 
 import odin
 from django.contrib.auth.models import AbstractUser
+from django.db import transaction
 from django.db.models import QuerySet
 from django.db.models.fields.files import ImageFieldFile
 from django.http import HttpRequest
@@ -13,6 +14,7 @@
 from .. import resources
 from ..resources.catalogue import Structure
 from ._common import map_queryset
+from ._model_mapper import ModelMapping
 
 __all__ = (
     "ProductImageToResource",
@@ -205,17 +207,17 @@ def map_stock_price(self) -> Tuple[Decimal, str, int]:
             return Decimal(0), "", 0
 
 
-class ProductToModel(odin.Mapping):
+class ProductToModel(ModelMapping):
     """Map from a product resource to a model."""
 
     from_obj = resources.catalogue.Product
     to_obj = ProductModel
 
-    # @odin.assign_field
-    # def images(self) -> List[ProductImageModel]:
-    #     """Map related image."""
-    #     return list(ProductImageToModel.apply(self.source.images, context=self.context))
-    #
+    @odin.map_list_field
+    def images(self, values) -> List[ProductImageModel]:
+        """Map related image."""
+        return list(ProductImageToModel.apply(values, context=self.context))
+
     # @odin.assign_field
     # def categories(self) -> List[CategoryModel]:
     #     """Map related categories."""
@@ -307,3 +309,22 @@ def product_to_model(
     """Map a product resource to a model."""
     model = ProductToModel.apply(product)
     return model
+
+
+def product_to_db(
+    product: resources.catalogue.Product,
+) -> ProductModel:
+    """Map a product resource to a model and store in the database.
+
+    The method will handle the nested database saves required to store the entire resource
+    within a single transaction.
+    """
+    model: ProductModel = product_to_model(product)
+
+    with transaction.atomic():
+        model.save()
+        for image in product.images:
+            image.product = model
+            image.save()
+
+    return model

tests/mappings/test_catalogue.py

@@ -42,12 +42,10 @@ def test_product_to_resource__where_is_a_parent_product_include_children(self):
         self.assertIsNotNone(actual.children)
         self.assertEqual(3, len(actual.children))
 
-    def test_product_to_model__basic_model_to_resource(self):
+    def test_product_to_db__basic_model_to_resource(self):
         product = Product.objects.first()
 
         resource = catalogue.product_to_resource(product)
-        actual = catalogue.product_to_model(resource)
-
-        actual.save()
+        actual = catalogue.product_to_db(resource)
 
         self.assertEqual(resource.title, actual.title)