fixup! Simplify from_django by relying in Pydantic. Add multiple leve…

…l relationship support.

.gitignore

@@ -131,4 +131,4 @@ dmypy.json
 .idea
 .DS_Store
 *.sublime-workspace
-.vscode
+.vscode

README.md

@@ -114,4 +114,112 @@ print(user_schema.json(indent=2))
 }
 ```
 
-See https://pydantic-docs.helpmanual.io/usage/exporting_models/ for more.
+See https://pydantic-docs.helpmanual.io/usage/exporting_models/ for more.
+
+### Use multiple level relations
+
+Djantic supports multiple level relations. Given the following models:
+
+```python
+class OrderUser(models.Model):
+    email = models.EmailField(unique=True)
+
+
+class OrderUserProfile(models.Model):
+    address = models.CharField(max_length=255)
+    user = models.OneToOneField(OrderUser, on_delete=models.CASCADE, related_name='profile')
+
+
+class Order(models.Model):
+    total_price = models.DecimalField(max_digits=8, decimal_places=5, default=0)
+    user = models.ForeignKey(
+        OrderUser, on_delete=models.CASCADE, related_name="orders"
+    )
+
+
+class OrderItem(models.Model):
+    price = models.DecimalField(max_digits=8, decimal_places=5, default=0)
+    quantity = models.IntegerField(default=0)
+    order = models.ForeignKey(
+        Order, on_delete=models.CASCADE, related_name="items"
+    )
+
+
+class OrderItemDetail(models.Model):
+    name = models.CharField(max_length=30)
+    order_item = models.ForeignKey(
+        OrderItem, on_delete=models.CASCADE, related_name="details"
+    )
+```
+
+Inverse ForeignKey relation (or M2M relation) type is a list of the Schema of this related object.
+
+OneToOne relation type is the Schema of this related object.
+
+```python
+class OrderItemDetailSchema(ModelSchema):
+    class Config:
+        model = OrderItemDetail
+
+class OrderItemSchema(ModelSchema):
+    details: List[OrderItemDetailSchema]
+
+    class Config:
+        model = OrderItem
+
+class OrderSchema(ModelSchema):
+    items: List[OrderItemSchema]
+
+    class Config:
+        model = Order
+
+class OrderUserProfileSchema(ModelSchema):
+    class Config:
+        model = OrderUserProfile
+
+class OrderUserSchema(ModelSchema):
+    orders: List[OrderSchema]
+    profile: OrderUserProfileSchema
+```
+
+**Calling:**
+
+```python
+user = OrderUser.objects.first()
+print(OrderUserSchema.from_orm(user).json(ident=4))
+```
+
+**Output:**
+```json
+{
+    "profile": {
+        "id": 1,
+        "address": "",
+        "user": 1
+    },
+    "orders": [
+        {
+            "items": [
+                {
+                    "details": [
+                        {
+                            "id": 1,
+                            "name": "",
+                            "order_item": 1
+                        }
+                    ],
+                    "id": 1,
+                    "price": 0.0,
+                    "quantity": 0,
+                    "order": 1
+                }
+            ],
+            "id": 1,
+            "total_price": 0.0,
+            "user": 1
+        }
+    ],
+    "id": 1,
+    "email": ""
+}
+```

djantic/main.py

@@ -43,7 +43,13 @@ def __new__(
                 and base == ModelSchema
             ):
 
-                config = namespace["Config"]
+                try:
+                    config = namespace["Config"]
+                except KeyError as exc:
+                    raise ConfigError(
+                        f"{exc} (Is `Config` class defined?)"
+                    )
+
                 include = getattr(config, "include", None)
                 exclude = getattr(config, "exclude", None)
 

tests/test_main.py

@@ -11,6 +11,13 @@ def test_config_errors():
     Test the model config error exceptions.
     """
 
+    with pytest.raises(
+        ConfigError, match="(Is `Config` class defined?)"
+    ):
+
+        class InvalidModelErrorSchema(ModelSchema):
+            pass
+
     with pytest.raises(
         ConfigError, match="(Is `Config.model` a valid Django model class?)"
     ):

tests/test_multiple_level_relations.py

@@ -3,7 +3,7 @@
 from typing import List
 
 import pytest
-from testapp.order import Order, OrderItem, OrderItemDetail, OrderUser, OrderUserFactory
+from testapp.order import Order, OrderItem, OrderItemDetail, OrderUser, OrderUserFactory, OrderUserProfile
 
 from djantic import ModelSchema
 
@@ -26,8 +26,14 @@ class OrderSchema(ModelSchema):
         class Config:
             model = Order
 
+    class OrderUserProfileSchema(ModelSchema):
+
+        class Config:
+            model = OrderUserProfile
+
     class OrderUserSchema(ModelSchema):
         orders: List[OrderSchema]
+        profile: OrderUserProfileSchema
 
         class Config:
             model = OrderUser
@@ -39,6 +45,11 @@ class Config:
         'first_name': '',
         'last_name': None,
         'email': '',
+        'profile': {
+            'id': 1,
+            'address': '',
+            'user': 1
+        },
         'orders': [
             {
                 'id': 1,
@@ -152,6 +163,9 @@ class Config:
         "description": "OrderUser(id, first_name, last_name, email)",
         "type": "object",
         "properties": {
+            "profile": {
+                "$ref": "#/definitions/OrderUserProfileSchema"
+            },
             "orders": {
                 "title": "Orders",
                 "type": "array",
@@ -184,11 +198,39 @@ class Config:
             }
         },
         "required": [
+            "profile",
             "orders",
             "first_name",
             "email"
         ],
         "definitions": {
+            "OrderUserProfileSchema": {
+                "title": "OrderUserProfileSchema",
+                "description": "OrderUserProfile(id, address, user)",
+                "type": "object",
+                "properties": {
+                    "id": {
+                        "title": "Id",
+                        "description": "id",
+                        "type": "integer"
+                    },
+                    "address": {
+                        "title": "Address",
+                        "description": "address",
+                        "maxLength": 255,
+                        "type": "string"
+                    },
+                    "user": {
+                        "title": "User",
+                        "description": "id",
+                        "type": "integer"
+                    }
+                },
+                "required": [
+                    "address",
+                    "user"
+                ]
+            },
             "OrderItemDetailSchema": {
                 "title": "OrderItemDetailSchema",
                 "description": "OrderItemDetail(id, name, value, quantity, order_item)",

tests/testapp/order.py

@@ -8,6 +8,12 @@ class OrderUser(models.Model):
     last_name = models.CharField(max_length=50, null=True, blank=True)
     email = models.EmailField(unique=True)
 
+
+class OrderUserProfile(models.Model):
+    address = models.CharField(max_length=255)
+    user = models.OneToOneField(OrderUser, on_delete=models.CASCADE, related_name='profile')
+
+
 class Order(models.Model):
     total_price = models.DecimalField(max_digits=8, decimal_places=5, default=0)
     shipping_address = models.CharField(max_length=255)
@@ -81,6 +87,12 @@ def items(self, create, items, **kwargs):
                      for i in range(0, 2)]
 
 
+class OrderUserProfileFactory(DjangoModelFactory):
+
+    class Meta:
+        model = OrderUserProfile
+
+
 class OrderUserFactory(DjangoModelFactory):
 
     class Meta:
@@ -90,3 +102,8 @@ class Meta:
     def orders(self, create, orders, **kwargs):
         if orders is None:
             orders = [OrderFactory.create(user=self, **kwargs) for i in range(0, 2)]
+
+    @factory.post_generation
+    def profile(self, create, profile, **kwargs):
+        if profile is None:
+            profile = OrderUserProfileFactory.create(user=self, **kwargs)