First pass at unique_for_date, unique_for_month, unique_for_year

rest_framework/fields.py

@@ -268,11 +268,17 @@ class Field(object):
         """
         errors = []
         for validator in self.validators:
-            if getattr(validator, 'requires_context', False):
-                validator.serializer_field = self
+            if hasattr(validator, 'set_context'):
+                validator.set_context(self)
+
             try:
                 validator(value)
             except ValidationError as exc:
+                # If the validation error contains a mapping of fields to
+                # errors then simply raise it immediately rather than
+                # attempting to accumulate a list of errors.
+                if isinstance(exc.detail, dict):
+                    raise
                 errors.extend(exc.detail)
             except DjangoValidationError as exc:
                 errors.extend(exc.messages)

rest_framework/serializers.py

@@ -23,7 +23,9 @@ from rest_framework.utils.field_mapping import (
     get_relation_kwargs, get_nested_relation_kwargs,
     ClassLookupDict
 )
-from rest_framework.validators import UniqueTogetherValidator
+from rest_framework.validators import (
+    UniqueForDateValidator, UniqueTogetherValidator
+)
 import copy
 import inspect
 import warnings
@@ -578,15 +580,9 @@ class ModelSerializer(Serializer):
         validators = []
         model_class = self.Meta.model
 
-        for unique_together in model_class._meta.unique_together:
-            if field_names.issuperset(set(unique_together)):
-                validator = UniqueTogetherValidator(
-                    queryset=model_class._default_manager,
-                    fields=unique_together
-                )
-                validators.append(validator)
-
-        for parent_class in model_class._meta.parents.keys():
+        # Note that we make sure to check `unique_together` both on the
+        # base model class, but also on any parent classes.
+        for parent_class in [model_class] + list(model_class._meta.parents.keys()):
             for unique_together in parent_class._meta.unique_together:
                 if field_names.issuperset(set(unique_together)):
                     validator = UniqueTogetherValidator(
@@ -595,6 +591,16 @@ class ModelSerializer(Serializer):
                     )
                     validators.append(validator)
 
+        info = model_meta.get_field_info(model_class)
+        for field_name, field in info.fields_and_pk.items():
+            if field.unique_for_date and field_name in field_names:
+                validator = UniqueForDateValidator(
+                    queryset=model_class._default_manager,
+                    field=field_name,
+                    date_field=field.unique_for_date
+                )
+                validators.append(validator)
+
         return validators
 
     def _get_base_fields(self):

rest_framework/validators.py

@@ -6,38 +6,36 @@ This gives us better separation of concerns, allows us to use single-step
 object creation, and makes it possible to switch between using the implicit
 `ModelSerializer` class and an equivelent explicit `Serializer` class.
 """
-from django.core.exceptions import ValidationError
 from django.utils.translation import ugettext_lazy as _
+from rest_framework.exceptions import ValidationError
 from rest_framework.utils.representation import smart_repr
 
 
 class UniqueValidator:
     """
     Validator that corresponds to `unique=True` on a model field.
+
+    Should be applied to an individual field on the serializer.
     """
-    # Validators with `requires_context` will have the field instance
-    # passed to them when the field is instantiated.
-    requires_context = True
     message = _('This field must be unique.')
 
     def __init__(self, queryset):
         self.queryset = queryset
         self.serializer_field = None
 
-    def __call__(self, value):
-        field = self.serializer_field
-
-        # Determine the model field name that the serializer field corresponds to.
-        field_name = field.source_attrs[0] if field.source_attrs else field.field_name
-
+    def set_context(self, serializer_field):
+        # Determine the underlying model field name. This may not be the
+        # same as the serializer field name if `source=<>` is set.
+        self.field_name = serializer_field.source_attrs[0]
         # Determine the existing instance, if this is an update operation.
-        instance = getattr(field.parent, 'instance', None)
+        self.instance = getattr(serializer_field.parent, 'instance', None)
 
+    def __call__(self, value):
         # Ensure uniqueness.
-        filter_kwargs = {field_name: value}
+        filter_kwargs = {self.field_name: value}
         queryset = self.queryset.filter(**filter_kwargs)
-        if instance:
-            queryset = queryset.exclude(pk=instance.pk)
+        if self.instance is not None:
+            queryset = queryset.exclude(pk=self.instance.pk)
         if queryset.exists():
             raise ValidationError(self.message)
 
@@ -51,8 +49,9 @@ class UniqueValidator:
 class UniqueTogetherValidator:
     """
     Validator that corresponds to `unique_together = (...)` on a model class.
+
+    Should be applied to the serializer class, not to an individual field.
     """
-    requires_context = True
     message = _('The fields {field_names} must make a unique set.')
 
     def __init__(self, queryset, fields):
@@ -60,19 +59,18 @@ class UniqueTogetherValidator:
         self.fields = fields
         self.serializer_field = None
 
-    def __call__(self, value):
-        serializer = self.serializer_field
-
+    def set_context(self, serializer):
         # Determine the existing instance, if this is an update operation.
-        instance = getattr(serializer, 'instance', None)
+        self.instance = getattr(serializer, 'instance', None)
 
+    def __call__(self, attrs):
         # Ensure uniqueness.
         filter_kwargs = dict([
-            (field_name, value[field_name]) for field_name in self.fields
+            (field_name, attrs[field_name]) for field_name in self.fields
         ])
         queryset = self.queryset.filter(**filter_kwargs)
-        if instance:
-            queryset = queryset.exclude(pk=instance.pk)
+        if self.instance is not None:
+            queryset = queryset.exclude(pk=self.instance.pk)
         if queryset.exists():
             field_names = ', '.join(self.fields)
             raise ValidationError(self.message.format(field_names=field_names))
@@ -83,3 +81,82 @@ class UniqueTogetherValidator:
             smart_repr(self.queryset),
             smart_repr(self.fields)
         )
+
+
+class BaseUniqueForValidator:
+    message = None
+
+    def __init__(self, queryset, field, date_field):
+        self.queryset = queryset
+        self.field = field
+        self.date_field = date_field
+
+    def set_context(self, serializer):
+        # Determine the underlying model field names. These may not be the
+        # same as the serializer field names if `source=<>` is set.
+        self.field_name = serializer.fields[self.field].source_attrs[0]
+        self.date_field_name = serializer.fields[self.date_field].source_attrs[0]
+        # Determine the existing instance, if this is an update operation.
+        self.instance = getattr(serializer, 'instance', None)
+
+    def get_filter_kwargs(self, attrs):
+        raise NotImplementedError('`get_filter_kwargs` must be implemented.')
+
+    def __call__(self, attrs):
+        filter_kwargs = self.get_filter_kwargs(attrs)
+
+        queryset = self.queryset.filter(**filter_kwargs)
+        if self.instance is not None:
+            queryset = queryset.exclude(pk=self.instance.pk)
+        if queryset.exists():
+            message = self.message.format(date_field=self.date_field)
+            raise ValidationError({self.field: message})
+
+    def __repr__(self):
+        return '<%s(queryset=%s, field=%s, date_field=%s)>' % (
+            self.__class__.__name__,
+            smart_repr(self.queryset),
+            smart_repr(self.field),
+            smart_repr(self.date_field)
+        )
+
+
+class UniqueForDateValidator(BaseUniqueForValidator):
+    message = _('This field must be unique for the "{date_field}" date.')
+
+    def get_filter_kwargs(self, attrs):
+        value = attrs[self.field]
+        date = attrs[self.date_field]
+
+        filter_kwargs = {}
+        filter_kwargs[self.field_name] = value
+        filter_kwargs['%s__day' % self.date_field_name] = date.day
+        filter_kwargs['%s__month' % self.date_field_name] = date.month
+        filter_kwargs['%s__year' % self.date_field_name] = date.year
+        return filter_kwargs
+
+
+class UniqueForMonthValidator(BaseUniqueForValidator):
+    message = _('This field must be unique for the "{date_field}" month.')
+
+    def get_filter_kwargs(self, attrs):
+        value = attrs[self.field]
+        date = attrs[self.date_field]
+
+        filter_kwargs = {}
+        filter_kwargs[self.field_name] = value
+        filter_kwargs['%s__month' % self.date_field_name] = date.month
+        return filter_kwargs
+
+
+class UniqueForYearValidator(BaseUniqueForValidator):
+    message = _('This field must be unique for the "{date_field}" year.')
+
+    def get_filter_kwargs(self, attrs):
+        value = attrs[self.field]
+        date = attrs[self.date_field]
+
+        filter_kwargs = {}
+        filter_kwargs[self.field_name] = value
+        filter_kwargs['%s__year' % self.date_field_name] = date.year
+        return filter_kwargs

tests/test_validators.py

@@ -1,6 +1,7 @@
 from django.db import models
 from django.test import TestCase
 from rest_framework import serializers
+import datetime
 
 
 def dedent(blocktext):
@@ -147,3 +148,70 @@ class TestUniquenessTogetherValidation(TestCase):
                 race_name = CharField(max_length=100)
         """)
         assert repr(serializer) == expected
+
+
+# Tests for `UniqueForDateValidator`
+# ----------------------------------
+
+class UniqueForDateModel(models.Model):
+    slug = models.CharField(max_length=100, unique_for_date='published')
+    published = models.DateField()
+
+
+class UniqueForDateSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = UniqueForDateModel
+
+
+class TestUniquenessForDateValidation(TestCase):
+    def setUp(self):
+        self.instance = UniqueForDateModel.objects.create(
+            slug='existing',
+            published='2000-01-01'
+        )
+
+    def test_repr(self):
+        serializer = UniqueForDateSerializer()
+        expected = dedent("""
+            UniqueForDateSerializer(validators=[<UniqueForDateValidator(queryset=UniqueForDateModel.objects.all(), field='slug', date_field='published')>]):
+                id = IntegerField(label='ID', read_only=True)
+                slug = CharField(max_length=100)
+                published = DateField()
+        """)
+        assert repr(serializer) == expected
+
+    def test_is_not_unique_for_date(self):
+        """
+        Failing unique for date validation should result in field error.
+        """
+        data = {'slug': 'existing', 'published': '2000-01-01'}
+        serializer = UniqueForDateSerializer(data=data)
+        assert not serializer.is_valid()
+        assert serializer.errors == {
+            'slug': ['This field must be unique for the "published" date.']
+        }
+
+    def test_is_unique_for_date(self):
+        """
+        Passing unique for date validation.
+        """
+        data = {'slug': 'existing', 'published': '2000-01-02'}
+        serializer = UniqueForDateSerializer(data=data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == {
+            'slug': 'existing',
+            'published': datetime.date(2000, 1, 2)
+        }
+
+    def test_updated_instance_excluded_from_unique_for_date(self):
+        """
+        When performing an update, the existing instance does not count
+        as a match against unique_for_date.
+        """
+        data = {'slug': 'existing', 'published': '2000-01-01'}
+        serializer = UniqueForDateSerializer(instance=self.instance, data=data)
+        assert serializer.is_valid()
+        assert serializer.validated_data == {
+            'slug': 'existing',
+            'published': datetime.date(2000, 1, 1)
+        }