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Lazy loading of fields and validators. Closes #1963.

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This commit is contained in:
Tom Christie 2014-10-31 16:38:39 +00:00
parent 11075d3770
commit 207208fedf
6 changed files with 54 additions and 30 deletions
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21
rest_framework/fields.py
View File

@ -143,7 +143,7 @@ class Field(object):
def __init__(self, read_only=False, write_only=False,
required=None, default=empty, initial=empty, source=None,
label=None, help_text=None, style=None,
error_messages=None, validators=[], allow_null=False):
error_messages=None, validators=None, allow_null=False):
self._creation_counter = Field._creation_counter
Field._creation_counter += 1
@ -166,9 +166,11 @@ class Field(object):
self.label = label
self.help_text = help_text
self.style = {} if style is None else style
self.validators = validators[:] or self.default_validators[:]
self.allow_null = allow_null
if validators is not None:
self.validators = validators[:]
# These are set up by `.bind()` when the field is added to a serializer.
self.field_name = None
self.parent = None
@ -214,6 +216,21 @@ class Field(object):
else:
self.source_attrs = self.source.split('.')
# .validators is a lazily loaded property, that gets its default
# value from `get_validators`.
@property
def validators(self):
if not hasattr(self, '_validators'):
self._validators = self.get_validators()
return self._validators
@validators.setter
def validators(self, validators):
self._validators = validators
def get_validators(self):
return self.default_validators[:]
def get_initial(self):
"""
Return a value to use when the field is being returned as a primitive

34
rest_framework/serializers.py
View File

@ -282,21 +282,23 @@ class SerializerMetaclass(type):
@six.add_metaclass(SerializerMetaclass)
class Serializer(BaseSerializer):
def __init__(self, *args, **kwargs):
super(Serializer, self).__init__(*args, **kwargs)
@property
def fields(self):
if not hasattr(self, '_fields'):
self._fields = BindingDict(self)
for key, value in self.get_fields().items():
self._fields[key] = value
return self._fields
def get_fields(self):
# Every new serializer is created with a clone of the field instances.
# This allows users to dynamically modify the fields on a serializer
# instance without affecting every other serializer class.
self.fields = BindingDict(self)
for key, value in self._get_base_fields().items():
self.fields[key] = value
self.validators = getattr(getattr(self, 'Meta', None), 'validators', [])
def _get_base_fields(self):
return copy.deepcopy(self._declared_fields)
def get_validators(self):
return getattr(getattr(self, 'Meta', None), 'validators', [])
def get_initial(self):
if self._initial_data is not None:
return ReturnDict([
@ -520,14 +522,6 @@ class ModelSerializer(Serializer):
})
_related_class = PrimaryKeyRelatedField
def __init__(self, *args, **kwargs):
super(ModelSerializer, self).__init__(*args, **kwargs)
if 'validators' not in kwargs:
validators = self.get_default_validators()
if validators:
self.validators.extend(validators)
self._kwargs['validators'] = validators
def create(self, validated_attrs):
# Check that the user isn't trying to handle a writable nested field.
# If we don't do this explicitly they'd likely get a confusing
@ -578,13 +572,13 @@ class ModelSerializer(Serializer):
instance.save()
return instance
def get_default_validators(self):
def get_validators(self):
field_names = set([
field.source for field in self.fields.values()
if (field.source != '*') and ('.' not in field.source)
])
validators = []
validators = getattr(getattr(self, 'Meta', None), 'validators', [])
model_class = self.Meta.model
# Note that we make sure to check `unique_together` both on the
@ -627,7 +621,7 @@ class ModelSerializer(Serializer):
return validators
def _get_base_fields(self):
def get_fields(self):
declared_fields = copy.deepcopy(self._declared_fields)
ret = SortedDict()

5
rest_framework/utils/representation.py
View File

@ -82,6 +82,11 @@ def serializer_repr(serializer, indent, force_many=None):
ret += field_repr(field.child_relation, force_many=field.child_relation)
else:
ret += field_repr(field)
if serializer.validators:
ret += '\n' + indent_str + 'class Meta:'
ret += '\n' + indent_str + ' validators = ' + smart_repr(serializer.validators)
return ret

4
tests/test_fields.py
View File

@ -85,7 +85,7 @@ class TestSource:
class ExampleSerializer(serializers.Serializer):
example_field = serializers.CharField(source='example_field')
with pytest.raises(AssertionError) as exc_info:
ExampleSerializer()
ExampleSerializer().fields
assert str(exc_info.value) == (
"It is redundant to specify `source='example_field'` on field "
"'CharField' in serializer 'ExampleSerializer', because it is the "
@ -1018,7 +1018,7 @@ class TestSerializerMethodField:
example_field = serializers.SerializerMethodField('get_example_field')
with pytest.raises(AssertionError) as exc_info:
ExampleSerializer()
ExampleSerializer().fields
assert str(exc_info.value) == (
"It is redundant to specify `get_example_field` on "
"SerializerMethodField 'example_field' in serializer "

4
tests/test_model_serializer.py
View File

@ -181,7 +181,7 @@ class TestRegularFieldMappings(TestCase):
fields = ('auto_field', 'invalid')
with self.assertRaises(ImproperlyConfigured) as excinfo:
TestSerializer()
TestSerializer().fields
expected = 'Field name `invalid` is not valid for model `ModelBase`.'
assert str(excinfo.exception) == expected
@ -198,7 +198,7 @@ class TestRegularFieldMappings(TestCase):
fields = ('auto_field',)
with self.assertRaises(ImproperlyConfigured) as excinfo:
TestSerializer()
TestSerializer().fields
expected = (
'Field `missing` has been declared on serializer '
'`TestSerializer`, but is missing from `Meta.fields`.'

16
tests/test_validators.py
View File

@ -86,10 +86,12 @@ class TestUniquenessTogetherValidation(TestCase):
def test_repr(self):
serializer = UniquenessTogetherSerializer()
expected = dedent("""
UniquenessTogetherSerializer(validators=[<UniqueTogetherValidator(queryset=UniquenessTogetherModel.objects.all(), fields=('race_name', 'position'))>]):
UniquenessTogetherSerializer():
id = IntegerField(label='ID', read_only=True)
race_name = CharField(max_length=100)
position = IntegerField()
class Meta:
validators = [<UniqueTogetherValidator(queryset=UniquenessTogetherModel.objects.all(), fields=('race_name', 'position'))>]
""")
assert repr(serializer) == expected
@ -173,10 +175,12 @@ class TestUniquenessForDateValidation(TestCase):
def test_repr(self):
serializer = UniqueForDateSerializer()
expected = dedent("""
UniqueForDateSerializer(validators=[<UniqueForDateValidator(queryset=UniqueForDateModel.objects.all(), field='slug', date_field='published')>]):
UniqueForDateSerializer():
id = IntegerField(label='ID', read_only=True)
slug = CharField(max_length=100)
published = DateField(required=True)
class Meta:
validators = [<UniqueForDateValidator(queryset=UniqueForDateModel.objects.all(), field='slug', date_field='published')>]
""")
assert repr(serializer) == expected
@ -231,10 +235,12 @@ class TestHiddenFieldUniquenessForDateValidation(TestCase):
serializer = TestSerializer()
expected = dedent("""
TestSerializer(validators=[<UniqueForDateValidator(queryset=HiddenFieldUniqueForDateModel.objects.all(), field='slug', date_field='published')>]):
TestSerializer():
id = IntegerField(label='ID', read_only=True)
slug = CharField(max_length=100)
published = HiddenField(default=CreateOnlyDefault(<function now>))
class Meta:
validators = [<UniqueForDateValidator(queryset=HiddenFieldUniqueForDateModel.objects.all(), field='slug', date_field='published')>]
""")
assert repr(serializer) == expected
@ -246,9 +252,11 @@ class TestHiddenFieldUniquenessForDateValidation(TestCase):
serializer = TestSerializer()
expected = dedent("""
TestSerializer(validators=[<UniqueForDateValidator(queryset=HiddenFieldUniqueForDateModel.objects.all(), field='slug', date_field='published')>]):
TestSerializer():
id = IntegerField(label='ID', read_only=True)
slug = CharField(max_length=100)
published = DateTimeField(default=CreateOnlyDefault(<function now>), read_only=True)
class Meta:
validators = [<UniqueForDateValidator(queryset=HiddenFieldUniqueForDateModel.objects.all(), field='slug', date_field='published')>]
""")
assert repr(serializer) == expected