From 4e634ca06804675294e646a1ba0f476768a9b546 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Tomasz=20Rydzy=C5=84ski?= Date: Fri, 17 Jul 2015 13:42:42 +0200 Subject: [PATCH] Add error codes to ValidationError This change addresses use cases that require more information about reported validation errors. Currently for each error that REST Framework reports users get only that error's message string. The message can be translated so there's no good way to recognize programmatically what sort of an error it is. When building an API that is supposed to return error codes, I've found it very limiting. For example, I was supposed to differentiate between missing fields and invalid arguments. This commit introduces proper error codes handling to the ValidationError. ValidationError can hold a single error itself (text), a list of those, or a dictionary mapping errors to fields. Error code is only meaningful for a single error, and I've added assertions to check for proper usage. To help with my development, I've added a setting that makes error code a mandatory argument. Thanks to this, I was able to correct all uses of ValidationError across the code. To maintain backward compatibility, I'm not passing error codes when building compound errors (e.g. a dictionary with all validation errors). However, users (me) can now monkey patch ValidationError.build_detail method, to store the codes. --- rest_framework/authtoken/serializers.py | 15 +++++++-- rest_framework/exceptions.py | 41 +++++++++++++++++++++++-- rest_framework/fields.py | 10 ++++-- rest_framework/serializers.py | 21 ++++++++++--- rest_framework/settings.py | 1 + rest_framework/validators.py | 16 +++++++--- tests/test_fields.py | 5 ++- tests/test_serializer.py | 28 ++++++++++++++++- tests/test_serializer_lists.py | 5 ++- tests/test_validation.py | 3 +- tests/test_validation_error.py | 38 +++++++++++++++++++++++ 11 files changed, 161 insertions(+), 22 deletions(-) create mode 100644 tests/test_validation_error.py diff --git a/rest_framework/authtoken/serializers.py b/rest_framework/authtoken/serializers.py index 8a295c03e..caf5b64b3 100644 --- a/rest_framework/authtoken/serializers.py +++ b/rest_framework/authtoken/serializers.py @@ -18,13 +18,22 @@ class AuthTokenSerializer(serializers.Serializer): if user: if not user.is_active: msg = _('User account is disabled.') - raise serializers.ValidationError(msg) + raise serializers.ValidationError( + msg, + code='authorization' + ) else: msg = _('Unable to log in with provided credentials.') - raise serializers.ValidationError(msg) + raise serializers.ValidationError( + msg, + code='authorization' + ) else: msg = _('Must include "username" and "password".') - raise serializers.ValidationError(msg) + raise serializers.ValidationError( + msg, + code='authorization' + ) attrs['user'] = user return attrs diff --git a/rest_framework/exceptions.py b/rest_framework/exceptions.py index 8447a9ded..37519b049 100644 --- a/rest_framework/exceptions.py +++ b/rest_framework/exceptions.py @@ -14,6 +14,7 @@ from django.utils.translation import ugettext_lazy as _ from django.utils.translation import ungettext from rest_framework import status +from rest_framework.settings import api_settings from rest_framework.utils.serializer_helpers import ReturnDict, ReturnList @@ -58,6 +59,14 @@ class APIException(Exception): return self.detail +def build_error_from_django_validation_error(exc_info): + code = getattr(exc_info, 'code', None) or 'invalid' + return [ + ValidationError.build_detail(msg, code=code) + for msg in exc_info.messages + ] + + # The recommended style for using `ValidationError` is to keep it namespaced # under `serializers`, in order to minimize potential confusion with Django's # built in `ValidationError`. For example: @@ -68,12 +77,40 @@ class APIException(Exception): class ValidationError(APIException): status_code = status.HTTP_400_BAD_REQUEST - def __init__(self, detail): + @staticmethod + def build_detail(detail, code=None): + """ + Create error's representation. + + This method is a helper that should be used when building compound + ValidationErrors directly (i.e. a whole list at once). Thanks to that + extra call, users have a customization point where they can tune how + much information about an error they want to see in the final output. + """ + if api_settings.REQUIRE_ERROR_CODES: + assert code is not None, ( + 'The `code` argument is required for single errors. ' + 'Strict checking of `code` is enabled with ' + 'REQUIRE_ERROR_CODES settings key.' + ) + + return detail + + def __init__(self, detail, code=None): # For validation errors the 'detail' key is always required. # The details should always be coerced to a list if not already. if not isinstance(detail, dict) and not isinstance(detail, list): - detail = [detail] + detail = [self.build_detail(detail, code)] + else: + if api_settings.REQUIRE_ERROR_CODES: + assert code is None, ( + 'The `code` argument must not be set for compound ' + 'errors. Strict checking of `code` is enabled with ' + 'REQUIRE_ERROR_CODES settings key.' + ) + self.detail = _force_text_recursive(detail) + self.code = code def __str__(self): return six.text_type(self.detail) diff --git a/rest_framework/fields.py b/rest_framework/fields.py index 0b214b872..e43ba6ac9 100644 --- a/rest_framework/fields.py +++ b/rest_framework/fields.py @@ -31,7 +31,9 @@ from rest_framework.compat import ( MinValueValidator, duration_string, parse_duration, unicode_repr, unicode_to_repr ) -from rest_framework.exceptions import ValidationError +from rest_framework.exceptions import ( + ValidationError, build_error_from_django_validation_error +) from rest_framework.settings import api_settings from rest_framework.utils import html, humanize_datetime, representation @@ -503,7 +505,9 @@ class Field(object): raise errors.extend(exc.detail) except DjangoValidationError as exc: - errors.extend(exc.messages) + errors.extend( + build_error_from_django_validation_error(exc) + ) if errors: raise ValidationError(errors) @@ -541,7 +545,7 @@ class Field(object): msg = MISSING_ERROR_MESSAGE.format(class_name=class_name, key=key) raise AssertionError(msg) message_string = msg.format(**kwargs) - raise ValidationError(message_string) + raise ValidationError(message_string, code=key) @cached_property def root(self): diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py index 35fb8fcf0..3cc4e34e0 100644 --- a/rest_framework/serializers.py +++ b/rest_framework/serializers.py @@ -20,6 +20,7 @@ from django.db.models.fields import FieldDoesNotExist from django.utils.functional import cached_property from django.utils.translation import ugettext_lazy as _ +from rest_framework import exceptions from rest_framework.compat import DurationField as ModelDurationField from rest_framework.compat import JSONField as ModelJSONField from rest_framework.compat import postgres_fields, unicode_to_repr @@ -300,7 +301,8 @@ def get_validation_error_detail(exc): # exception class as well for simpler compat. # Eg. Calling Model.clean() explicitly inside Serializer.validate() return { - api_settings.NON_FIELD_ERRORS_KEY: list(exc.messages) + api_settings.NON_FIELD_ERRORS_KEY: + exceptions.build_error_from_django_validation_error(exc) } elif isinstance(exc.detail, dict): # If errors may be a dict we use the standard {key: list of values}. @@ -422,8 +424,9 @@ class Serializer(BaseSerializer): message = self.error_messages['invalid'].format( datatype=type(data).__name__ ) + error = ValidationError.build_detail(message, code='invalid') raise ValidationError({ - api_settings.NON_FIELD_ERRORS_KEY: [message] + api_settings.NON_FIELD_ERRORS_KEY: [error] }) ret = OrderedDict() @@ -440,7 +443,9 @@ class Serializer(BaseSerializer): except ValidationError as exc: errors[field.field_name] = exc.detail except DjangoValidationError as exc: - errors[field.field_name] = list(exc.messages) + errors[field.field_name] = ( + exceptions.build_error_from_django_validation_error(exc) + ) except SkipField: pass else: @@ -560,7 +565,9 @@ class ListSerializer(BaseSerializer): value = self.validate(value) assert value is not None, '.validate() should return the validated data' except (ValidationError, DjangoValidationError) as exc: - raise ValidationError(detail=get_validation_error_detail(exc)) + raise ValidationError( + detail=get_validation_error_detail(exc) + ) return value @@ -575,8 +582,12 @@ class ListSerializer(BaseSerializer): message = self.error_messages['not_a_list'].format( input_type=type(data).__name__ ) + error = ValidationError.build_detail( + message, + code='not_a_list' + ) raise ValidationError({ - api_settings.NON_FIELD_ERRORS_KEY: [message] + api_settings.NON_FIELD_ERRORS_KEY: [error] }) if not self.allow_empty and len(data) == 0: diff --git a/rest_framework/settings.py b/rest_framework/settings.py index adf737126..640d73f80 100644 --- a/rest_framework/settings.py +++ b/rest_framework/settings.py @@ -83,6 +83,7 @@ DEFAULTS = { # Exception handling 'EXCEPTION_HANDLER': 'rest_framework.views.exception_handler', 'NON_FIELD_ERRORS_KEY': 'non_field_errors', + 'REQUIRE_ERROR_CODES': False, # Testing 'TEST_REQUEST_RENDERER_CLASSES': ( diff --git a/rest_framework/validators.py b/rest_framework/validators.py index a21f67e60..66e3d4bc1 100644 --- a/rest_framework/validators.py +++ b/rest_framework/validators.py @@ -60,7 +60,7 @@ class UniqueValidator(object): queryset = self.filter_queryset(value, queryset) queryset = self.exclude_current_instance(queryset) if queryset.exists(): - raise ValidationError(self.message) + raise ValidationError(self.message, code='unique') def __repr__(self): return unicode_to_repr('<%s(queryset=%s)>' % ( @@ -101,7 +101,9 @@ class UniqueTogetherValidator(object): return missing = { - field_name: self.missing_message + field_name: ValidationError.build_detail( + self.missing_message, + code='required') for field_name in self.fields if field_name not in attrs } @@ -147,7 +149,8 @@ class UniqueTogetherValidator(object): ] if None not in checked_values and queryset.exists(): field_names = ', '.join(self.fields) - raise ValidationError(self.message.format(field_names=field_names)) + raise ValidationError(self.message.format(field_names=field_names), + code='unique') def __repr__(self): return unicode_to_repr('<%s(queryset=%s, fields=%s)>' % ( @@ -185,7 +188,9 @@ class BaseUniqueForValidator(object): 'required' state on the fields they are applied to. """ missing = { - field_name: self.missing_message + field_name: ValidationError.build_detail( + self.missing_message, + code='required') for field_name in [self.field, self.date_field] if field_name not in attrs } @@ -211,7 +216,8 @@ class BaseUniqueForValidator(object): queryset = self.exclude_current_instance(attrs, queryset) if queryset.exists(): message = self.message.format(date_field=self.date_field) - raise ValidationError({self.field: message}) + error = ValidationError.build_detail(message, code='unique') + raise ValidationError({self.field: error}) def __repr__(self): return unicode_to_repr('<%s(queryset=%s, field=%s, date_field=%s)>' % ( diff --git a/tests/test_fields.py b/tests/test_fields.py index 104337627..98141aea4 100644 --- a/tests/test_fields.py +++ b/tests/test_fields.py @@ -1392,7 +1392,10 @@ class TestFieldFieldWithName(FieldValues): # call into it's regular validation, or require PIL for testing. class FailImageValidation(object): def to_python(self, value): - raise serializers.ValidationError(self.error_messages['invalid_image']) + raise serializers.ValidationError( + self.error_messages['invalid_image'], + code='invalid_image' + ) class PassImageValidation(object): diff --git a/tests/test_serializer.py b/tests/test_serializer.py index 741c6ab17..a0219527a 100644 --- a/tests/test_serializer.py +++ b/tests/test_serializer.py @@ -7,6 +7,7 @@ import pytest from rest_framework import serializers from rest_framework.compat import unicode_repr +from rest_framework.fields import DjangoValidationError from .utils import MockObject @@ -69,7 +70,10 @@ class TestValidateMethod: integer = serializers.IntegerField() def validate(self, attrs): - raise serializers.ValidationError('Non field error') + raise serializers.ValidationError( + 'Non field error', + code='test' + ) serializer = ExampleSerializer(data={'char': 'abc', 'integer': 123}) assert not serializer.is_valid() @@ -309,3 +313,25 @@ class TestCacheSerializerData: pickled = pickle.dumps(serializer.data) data = pickle.loads(pickled) assert data == {'field1': 'a', 'field2': 'b'} + + +class TestGetValidationErrorDetail: + def test_get_validation_error_detail_converts_django_errors(self): + exc = DjangoValidationError("Missing field.", code='required') + detail = serializers.get_validation_error_detail(exc) + assert detail == {'non_field_errors': ['Missing field.']} + + +class TestCapturingDjangoValidationError: + def test_django_validation_error_on_a_field_is_converted(self): + class ExampleSerializer(serializers.Serializer): + field = serializers.CharField() + + def validate_field(self, value): + raise DjangoValidationError( + 'validation failed' + ) + + serializer = ExampleSerializer(data={'field': 'a'}) + assert not serializer.is_valid() + assert serializer.errors == {'field': ['validation failed']} diff --git a/tests/test_serializer_lists.py b/tests/test_serializer_lists.py index 607ddba04..81aed3574 100644 --- a/tests/test_serializer_lists.py +++ b/tests/test_serializer_lists.py @@ -280,7 +280,10 @@ class TestListSerializerClass: def test_list_serializer_class_validate(self): class CustomListSerializer(serializers.ListSerializer): def validate(self, attrs): - raise serializers.ValidationError('Non field error') + raise serializers.ValidationError( + 'Non field error', + code='test' + ) class TestSerializer(serializers.Serializer): class Meta: diff --git a/tests/test_validation.py b/tests/test_validation.py index 855ff20e0..26a04fb66 100644 --- a/tests/test_validation.py +++ b/tests/test_validation.py @@ -41,7 +41,8 @@ class ShouldValidateModelSerializer(serializers.ModelSerializer): def validate_renamed(self, value): if len(value) < 3: - raise serializers.ValidationError('Minimum 3 characters.') + raise serializers.ValidationError('Minimum 3 characters.', + code='min_length') return value class Meta: diff --git a/tests/test_validation_error.py b/tests/test_validation_error.py new file mode 100644 index 000000000..5ceb60859 --- /dev/null +++ b/tests/test_validation_error.py @@ -0,0 +1,38 @@ +import pytest +from django.test import TestCase + +from rest_framework import serializers +from rest_framework.settings import api_settings + + +class TestMandatoryErrorCodeArgument(TestCase): + """ + If mandatory error code is enabled in settings, it should prevent throwing + ValidationError without the code set. + """ + def setUp(self): + self.DEFAULT_REQUIRE_ERROR_CODES = api_settings.REQUIRE_ERROR_CODES + api_settings.REQUIRE_ERROR_CODES = True + + def tearDown(self): + api_settings.REQUIRE_ERROR_CODES = self.DEFAULT_REQUIRE_ERROR_CODES + + def test_validation_error_requires_code_for_simple_messages(self): + with pytest.raises(AssertionError): + serializers.ValidationError("") + + def test_validation_error_requires_no_code_for_structured_errors(self): + """ + ValidationError can hold a list or dictionary of simple errors, in + which case the code is no longer meaningful and should not be + specified. + """ + with pytest.raises(AssertionError): + serializers.ValidationError([], code='min_value') + + with pytest.raises(AssertionError): + serializers.ValidationError({}, code='min_value') + + def test_validation_error_stores_error_code(self): + exception = serializers.ValidationError("", code='min_value') + assert exception.code == 'min_value'