fix ObjectId in forms

Author: timgraham

.github/workflows/runtests.py

@@ -56,6 +56,7 @@
     "force_insert_update",
     "foreign_object",
     "forms_tests",
+    "forms_tests_",
     "from_db_value",
     "generic_inline_admin",
     "generic_relations",

django_mongodb/fields/objectid.py

@@ -3,10 +3,12 @@
 from django.db.models.fields import Field
 from django.utils.translation import gettext_lazy as _
 
+from django_mongodb import forms
+
 
 class ObjectIdMixin:
     default_error_messages = {
-        "invalid": _("“%(value)s” value must be an Object Id."),
+        "invalid": _("“%(value)s” is not a valid Object Id."),
     }
     description = _("Object Id")
 
@@ -17,12 +19,8 @@ def rel_db_type(self, connection):
         return "objectId"
 
     def get_prep_value(self, value):
-        if value is None or isinstance(value, ObjectId):
-            return value
-        try:
-            return ObjectId(value)
-        except (errors.InvalidId, TypeError) as e:
-            raise ValueError(f"Field '{self.name}' expected an ObjectId but got {value!r}.") from e
+        value = super().get_prep_value(value)
+        return self.to_python(value)
 
     def to_python(self, value):
         if value is None:
@@ -36,6 +34,14 @@ def to_python(self, value):
                 params={"value": value},
             ) from None
 
+    def formfield(self, **kwargs):
+        return super().formfield(
+            **{
+                "form_class": forms.ObjectIdField,
+                **kwargs,
+            }
+        )
+
 
 class ObjectIdField(ObjectIdMixin, Field):
     def deconstruct(self):

django_mongodb/forms/__init__.py

@@ -0,0 +1,3 @@
+from .fields import ObjectIdField
+
+__all__ = ["ObjectIdField"]

django_mongodb/forms/fields.py

@@ -0,0 +1,27 @@
+from bson import ObjectId
+from bson.errors import InvalidId
+from django.core.exceptions import ValidationError
+from django.forms import Field
+from django.utils.translation import gettext_lazy as _
+
+
+class ObjectIdField(Field):
+    default_error_messages = {
+        "invalid": _("Enter a valid Object Id."),
+    }
+
+    def prepare_value(self, value):
+        if isinstance(value, ObjectId):
+            return str(value)
+        return value
+
+    def to_python(self, value):
+        value = super().to_python(value)
+        if value in self.empty_values:
+            return None
+        if not isinstance(value, ObjectId):
+            try:
+                value = ObjectId(value)
+            except InvalidId:
+                raise ValidationError(self.error_messages["invalid"], code="invalid") from None
+        return value

docs/source/forms.rst

@@ -0,0 +1,13 @@
+Forms API reference
+===================
+
+.. module:: django_mongodb.forms
+
+Some MongoDB-specific fields are available in ``django_mongodb.forms``.
+
+``ObjectIdField``
+-----------------
+
+.. class:: ObjectIdField
+
+Stores an :class:`~bson.objectid.ObjectId`.

docs/source/index.rst

@@ -7,6 +7,7 @@ django-mongodb 5.0.x documentation
 
    fields
    querysets
+   forms
 
 Indices and tables
 ==================

tests/forms_tests_/__init__.py

@@ -0,0 +1,33 @@
+from bson import ObjectId
+from django.core.exceptions import ValidationError
+from django.test import SimpleTestCase
+
+from django_mongodb.forms.fields import ObjectIdField
+
+
+class ObjectIdFieldTests(SimpleTestCase):
+    def test_clean(self):
+        field = ObjectIdField()
+        value = field.clean("675747ec45260945758d76bc")
+        self.assertEqual(value, ObjectId("675747ec45260945758d76bc"))
+
+    def test_clean_objectid(self):
+        field = ObjectIdField()
+        value = field.clean(ObjectId("675747ec45260945758d76bc"))
+        self.assertEqual(value, ObjectId("675747ec45260945758d76bc"))
+
+    def test_clean_empty_string(self):
+        field = ObjectIdField(required=False)
+        value = field.clean("")
+        self.assertEqual(value, None)
+
+    def test_clean_invalid(self):
+        field = ObjectIdField()
+        with self.assertRaises(ValidationError) as cm:
+            field.clean("invalid")
+        self.assertEqual(cm.exception.messages[0], "Enter a valid Object Id.")
+
+    def test_prepare_value(self):
+        field = ObjectIdField()
+        value = field.prepare_value(ObjectId("675747ec45260945758d76bc"))
+        self.assertEqual(value, "675747ec45260945758d76bc")

tests/forms_tests_/test_objectidfield.py

@@ -2,6 +2,7 @@
 from django.core.exceptions import ValidationError
 from django.test import SimpleTestCase, TestCase
 
+from django_mongodb import forms
 from django_mongodb.fields import ObjectIdField
 
 from .models import NullableObjectIdModel, ObjectIdModel, PrimaryKeyObjectIdModel
@@ -15,6 +16,10 @@ def test_deconstruct(self):
         self.assertEqual(args, [])
         self.assertEqual(kwargs, {})
 
+    def test_formfield(self):
+        f = ObjectIdField().formfield()
+        self.assertIsInstance(f, forms.ObjectIdField)
+
     def test_get_internal_type(self):
         f = ObjectIdField()
         self.assertEqual(f.get_internal_type(), "ObjectIdField")
@@ -32,9 +37,9 @@ def test_to_python_null(self):
 
     def test_to_python_invalid_value(self):
         f = ObjectIdField()
-        for invalid_value in ["None", {}, [], 123]:
+        for invalid_value in ["None", "", {}, [], 123]:
             with self.subTest(invalid_value=invalid_value):
-                msg = f"['“{invalid_value}” value must be an Object Id.']"
+                msg = f"['“{invalid_value}” is not a valid Object Id.']"
                 with self.assertRaisesMessage(ValidationError, msg):
                     f.to_python(invalid_value)
 
@@ -46,22 +51,16 @@ def test_get_prep_value_objectid(self):
         value = ObjectId("1" * 24)
         self.assertEqual(ObjectIdField().get_prep_value(value), value)
 
-    def test_get_prep_value_empty(self):
-        # This is necessary to allow an empty ObjectIdField to be saved in
-        # forms, unless we add an ObjectId form field to do the conversion (see
-        # UUIDField for an example).
-        self.assertIsNone(ObjectIdField().get_prep_value(""))
-
     def test_get_prep_value_null(self):
         self.assertIsNone(ObjectIdField().get_prep_value(None))
 
     def test_get_prep_value_invalid_values(self):
         f = ObjectIdField()
         f.name = "test"
-        for invalid_value in ["None", {}, [], 123]:
+        for invalid_value in ["None", "", {}, [], 123]:
             with self.subTest(invalid_value=invalid_value):
-                msg = f"Field 'test' expected an ObjectId but got {invalid_value!r}."
-                with self.assertRaisesMessage(ValueError, msg):
+                msg = f"['“{invalid_value}” is not a valid Object Id.']"
+                with self.assertRaisesMessage(ValidationError, msg):
                     f.get_prep_value(invalid_value)
 
 
@@ -82,17 +81,16 @@ def test_null_handling(self):
         self.assertIsNone(loaded.field)
 
     def test_pk_validated(self):
-        # See https://code.djangoproject.com/ticket/24859
-        with self.assertRaisesMessage(TypeError, "must be an Object Id."):
+        with self.assertRaisesMessage(ValidationError, "is not a valid Object Id."):
             PrimaryKeyObjectIdModel.objects.get(pk={})
 
-        with self.assertRaisesMessage(TypeError, "must be an Object Id."):
+        with self.assertRaisesMessage(ValidationError, "is not a valid Object Id."):
             PrimaryKeyObjectIdModel.objects.get(pk=[])
 
     def test_wrong_value(self):
         # Copied from  UUID tests. Raises ValueError, might be okay.
-        with self.assertRaisesMessage(ValidationError, "must be an Object Id."):
+        with self.assertRaisesMessage(ValidationError, "is not a valid Object Id."):
             ObjectIdModel.objects.get(field="not-a-objectid")
 
-        with self.assertRaisesMessage(ValidationError, "must be an Object Id."):
+        with self.assertRaisesMessage(ValidationError, "is not a valid Object Id."):
             ObjectIdModel.objects.create(field="not-a-objectid")