extend ModelMixin.

Author: flask-pro

.python-version

@@ -1 +1 @@
-3.12
+3.14

CHANGES.md

@@ -1,3 +1,8 @@
+## Version 4.2.0
+
+* Add method `.to_dict()` to `ModelMixin`.
+* Add validate UTC timezone for datetime field in `ModelMixine`.
+
 ## Version 4.1.0
 
 * Add bulk methods to `CreateMixin`, `ReadMixin`, `UpdateMixin` and `DeleteMixin` mixins.

Makefile

@@ -23,7 +23,7 @@ format: venv
 
 test: venv
 	# Run pytest.
-	./venv/bin/pytest -x --cov-report term-missing:skip-covered --cov=db_first tests/
+	./venv/bin/pytest -x --cov-report term-missing:skip-covered --cov=src/db_first tests/
 
 tox: venv
 	# Testing project via several Python versions.

pyproject.toml

@@ -25,15 +25,15 @@ license = {file = "LICENSE"}
 name = "DB-First"
 readme = "README.md"
 requires-python = ">=3.9"
-version = "4.1.0"
+version = "4.2.0"
 
 [project.optional-dependencies]
 dev = [
   "build==1.3.0",
   "pre-commit==4.3.0",
   "pytest==8.4.2",
   "pytest-cov==7.0.0",
-  "python-dotenv==1.1.1",
+  "python-dotenv==1.2.1",
   "tox==4.30.3",
   "twine==6.2.0"
 ]

src/db_first/base_model.py

@@ -1,9 +1,12 @@
 import uuid
 from datetime import datetime
+from datetime import timezone
 from typing import Optional
 
+from sqlalchemy import DateTime
 from sqlalchemy.orm import Mapped
 from sqlalchemy.orm import mapped_column
+from sqlalchemy.orm import validates
 
 
 def make_uuid4() -> uuid.UUID:
@@ -13,10 +16,56 @@ def make_uuid4() -> uuid.UUID:
 class ModelMixin:
     """Mixin for table model."""
 
+    EMPTY_VALUES: tuple[None, list, dict, tuple] = (None, [], {}, ())
+
     id: Mapped[uuid.UUID] = mapped_column(primary_key=True, default=make_uuid4, comment='UUID')
     created_at: Mapped[datetime] = mapped_column(
-        default=datetime.utcnow, comment='Date and time created'
+        DateTime(timezone=True), default=datetime.utcnow, comment='Date and time created'
     )
     updated_at: Mapped[Optional[datetime]] = mapped_column(
-        onupdate=datetime.utcnow, comment='Date and time updated'
+        DateTime(timezone=True), onupdate=datetime.utcnow, comment='Date and time updated'
     )
+
+    @staticmethod
+    def validate_utc_timezone(key: str, value: datetime or None) -> datetime:
+        time_zone = getattr(value, 'tzinfo', None)
+        if time_zone != timezone.utc:
+            raise ValueError(
+                f'Field <{key}> must be datetime with UTC timezone,'
+                f' but received timezone: <{time_zone}>'
+            )
+
+        return value
+
+    @validates('created_at', 'updated_at')
+    def validate_timezone(self, key, value) -> datetime:
+        return self.validate_utc_timezone(key, value)
+
+    def to_dict(self, fields: dict[str, dict or list or Ellipsis]):
+        data = {}
+        for field, value in fields.items():
+            value_from_db = None
+
+            if value is Ellipsis:
+                value_from_db = getattr(self, field)
+
+            elif isinstance(value, dict):
+                obj = getattr(self, field)
+                if obj:
+                    value_from_db = obj.to_dict(value)
+
+            elif isinstance(value, list):
+                value_from_db = []
+                for obj in getattr(self, field):
+                    for item in value:
+                        dictable_value_from_db = obj.to_dict(item)
+                        if dictable_value_from_db not in self.EMPTY_VALUES:
+                            value_from_db.append(dictable_value_from_db)
+
+            else:
+                value_from_db = self.to_dict(value)
+
+            if value_from_db not in self.EMPTY_VALUES:
+                data[field] = value_from_db
+
+        return data

tests/test_model_mixin.py

@@ -0,0 +1,33 @@
+from datetime import datetime
+
+import pytest
+
+
+def test_model_mixin__to_dict(fx_parents__non_deletion):
+    new_parent = fx_parents__non_deletion()
+
+    assert new_parent.to_dict(
+        {
+            'id': ...,
+            'first': ...,
+            'father': {'id': ..., 'first': ...},
+            'children': [{'id': ..., 'first': ...}],
+        }
+    ) == {
+        'id': new_parent.id,
+        'first': new_parent.first,
+        'father': {'first': new_parent.father.first, 'id': new_parent.father.id},
+        'children': [{'first': new_parent.children[0].first, 'id': new_parent.children[0].id}],
+    }
+
+
+@pytest.mark.parametrize('date_time', ['', None, 'not_date_time', datetime.now()])
+def test_model_mixin__validate_timezone(fx_db, date_time):
+    session, _, _, Fathers = fx_db
+
+    with pytest.raises(ValueError) as e:
+        Fathers(first='first', created_at=date_time)
+
+    assert e.value.args[0] == (
+        'Field <created_at> must be datetime with UTC timezone, but received timezone: <None>'
+    )