Clean up relational fields queryset usage

rest_framework/fields.py

@@ -508,7 +508,7 @@ class DecimalField(Field):
 
 class DateField(Field):
     default_error_messages = {
-        'invalid': _("Date has wrong format. Use one of these formats instead: %s"),
+        'invalid': _('Date has wrong format. Use one of these formats instead: {format}'),
     }
     input_formats = api_settings.DATE_INPUT_FORMATS
     format = api_settings.DATE_FORMAT
@@ -551,8 +551,7 @@ class DateField(Field):
                     return parsed.date()
 
         humanized_format = humanize_datetime.date_formats(self.input_formats)
-        msg = self.error_messages['invalid'] % humanized_format
-        raise ValidationError(msg)
+        self.fail('invalid', format=humanized_format)
 
     def to_representation(self, value):
         if value is None or self.format is None:
@@ -568,7 +567,7 @@ class DateField(Field):
 
 class DateTimeField(Field):
     default_error_messages = {
-        'invalid': _("Datetime has wrong format. Use one of these formats instead: %s"),
+        'invalid': _('Datetime has wrong format. Use one of these formats instead: {format}'),
     }
     input_formats = api_settings.DATETIME_INPUT_FORMATS
     format = api_settings.DATETIME_FORMAT
@@ -617,8 +616,7 @@ class DateTimeField(Field):
                     return parsed
 
         humanized_format = humanize_datetime.datetime_formats(self.input_formats)
-        msg = self.error_messages['invalid'] % humanized_format
-        raise ValidationError(msg)
+        self.fail('invalid', format=humanized_format)
 
     def to_representation(self, value):
         if value is None or self.format is None:
@@ -634,7 +632,7 @@ class DateTimeField(Field):
 
 class TimeField(Field):
     default_error_messages = {
-        'invalid': _("Time has wrong format. Use one of these formats instead: %s"),
+        'invalid': _('Time has wrong format. Use one of these formats instead: {format}'),
     }
     input_formats = api_settings.TIME_INPUT_FORMATS
     format = api_settings.TIME_FORMAT
@@ -669,8 +667,7 @@ class TimeField(Field):
                     return parsed.time()
 
         humanized_format = humanize_datetime.time_formats(self.input_formats)
-        msg = self.error_messages['invalid'] % humanized_format
-        raise ValidationError(msg)
+        self.fail('invalid', format=humanized_format)
 
     def to_representation(self, value):
         if value is None or self.format is None:

rest_framework/generics.py

@@ -216,7 +216,7 @@ class GenericAPIView(views.APIView):
         )
 
         queryset = self.queryset
-        if isinstance(self.queryset, QuerySet):
+        if isinstance(queryset, QuerySet):
             # Ensure queryset is re-evaluated on each request.
             queryset = queryset.all()
         return queryset

rest_framework/relations.py

@@ -2,28 +2,35 @@ from rest_framework.fields import Field
 from rest_framework.reverse import reverse
 from django.core.exceptions import ObjectDoesNotExist
 from django.core.urlresolvers import resolve, get_script_prefix, NoReverseMatch
+from django.db.models.query import QuerySet
 from rest_framework.compat import urlparse
 
 
-def get_default_queryset(serializer_class, field_name):
-    manager = getattr(serializer_class.opts.model, field_name)
-    if hasattr(manager, 'related'):
-        # Forward relationships
-        return manager.related.model._default_manager.all()
-    # Reverse relationships
-    return manager.field.rel.to._default_manager.all()
-
-
 class RelatedField(Field):
     def __init__(self, **kwargs):
         self.queryset = kwargs.pop('queryset', None)
         self.many = kwargs.pop('many', False)
+        assert self.queryset is not None or kwargs.get('read_only', False), (
+            'Relational field must provide a `queryset` argument, '
+            'or set read_only=`True`.'
+        )
         super(RelatedField, self).__init__(**kwargs)
 
-    def bind(self, field_name, parent, root):
-        super(RelatedField, self).bind(field_name, parent, root)
-        if self.queryset is None and not self.read_only:
-            self.queryset = get_default_queryset(parent, self.source)
+    def get_queryset(self):
+        queryset = self.queryset
+        if isinstance(queryset, QuerySet):
+            # Ensure queryset is re-evaluated whenever used.
+            queryset = queryset.all()
+        return queryset
+
+
+class StringRelatedField(Field):
+    def __init__(self, **kwargs):
+        kwargs['read_only'] = True
+        super(StringRelatedField, self).__init__(**kwargs)
+
+    def to_representation(self, value):
+        return str(value)
 
 
 class PrimaryKeyRelatedField(RelatedField):
@@ -33,9 +40,9 @@ class PrimaryKeyRelatedField(RelatedField):
         'incorrect_type': 'Incorrect type.  Expected pk value, received {data_type}.',
     }
 
-    def from_native(self, data):
+    def to_internal_value(self, data):
         try:
-            return self.queryset.get(pk=data)
+            return self.get_queryset().get(pk=data)
         except ObjectDoesNotExist:
             self.fail('does_not_exist', pk_value=data)
         except (TypeError, ValueError):
@@ -68,9 +75,9 @@ class HyperlinkedRelatedField(RelatedField):
         """
         lookup_value = view_kwargs[self.lookup_url_kwarg]
         lookup_kwargs = {self.lookup_field: lookup_value}
-        return self.queryset.get(**lookup_kwargs)
+        return self.get_queryset().get(**lookup_kwargs)
 
-    def from_native(self, value):
+    def to_internal_value(self, value):
         try:
             http_prefix = value.startswith(('http:', 'https:'))
         except AttributeError:
@@ -102,13 +109,26 @@ class HyperlinkedIdentityField(RelatedField):
 
     def __init__(self, **kwargs):
         kwargs['read_only'] = True
+        kwargs['source'] = '*'
         self.view_name = kwargs.pop('view_name')
         self.lookup_field = kwargs.pop('lookup_field', self.lookup_field)
         self.lookup_url_kwarg = kwargs.pop('lookup_url_kwarg', self.lookup_field)
         super(HyperlinkedIdentityField, self).__init__(**kwargs)
 
-    def get_attribute(self, instance):
-        return instance
+    def get_url(self, obj, view_name, request, format):
+        """
+        Given an object, return the URL that hyperlinks to the object.
+
+        May raise a `NoReverseMatch` if the `view_name` and `lookup_field`
+        attributes are not configured to correctly match the URL conf.
+        """
+        # Unsaved objects will not yet have a valid URL.
+        if obj.pk is None:
+            return None
+
+        lookup_value = getattr(obj, self.lookup_field)
+        kwargs = {self.lookup_url_kwarg: lookup_value}
+        return reverse(view_name, kwargs=kwargs, request=request, format=format)
 
     def to_representation(self, value):
         request = self.context.get('request', None)
@@ -144,21 +164,6 @@ class HyperlinkedIdentityField(RelatedField):
             )
             raise Exception(msg % self.view_name)
 
-    def get_url(self, obj, view_name, request, format):
-        """
-        Given an object, return the URL that hyperlinks to the object.
-
-        May raise a `NoReverseMatch` if the `view_name` and `lookup_field`
-        attributes are not configured to correctly match the URL conf.
-        """
-        # Unsaved objects will not yet have a valid URL.
-        if obj.pk is None:
-            return None
-
-        lookup_value = getattr(obj, self.lookup_field)
-        kwargs = {self.lookup_url_kwarg: lookup_value}
-        return reverse(view_name, kwargs=kwargs, request=request, format=format)
-
 
 class SlugRelatedField(RelatedField):
     def __init__(self, **kwargs):

tests/test_generics.py

@@ -547,7 +547,9 @@ class ClassA(models.Model):
 
 
 class ClassASerializer(serializers.ModelSerializer):
-    childs = serializers.PrimaryKeyRelatedField(many=True, source='childs')
+    childs = serializers.PrimaryKeyRelatedField(
+        many=True, queryset=ClassB.objects.all()
+    )
 
     class Meta:
         model = ClassA