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Commit f387cd89 by Tom Christie
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Uniqueness constraints imply a forced 'required=True'. Refs #1945

parent 93633c29
Showing with 100 additions and 16 deletions
docs/api-guide/validators.md
......@@ -93,6 +93,12 @@ The validator should be applied to *serializer classes*, like so:
)
]
---
**Note**: The `UniqueTogetherValidation` class always imposes an implicit constraint that all the fields it applies to are always treated as required. Fields with `default` values are an exception to this as they always supply a value even when omitted from user input.
---
## UniqueForDateValidator
## UniqueForMonthValidator
......@@ -146,6 +152,10 @@ If you want the date field to be entirely hidden from the user, then use `Hidden
---
**Note**: The `UniqueFor<Range>Validation` classes always imposes an implicit constraint that the fields they are applied to are always treated as required. Fields with `default` values are an exception to this as they always supply a value even when omitted from user input.
---
# Writing custom validators
You can use any of Django's existing validators, or write your own custom validators.
......
rest_framework/validators.py
......@@ -25,6 +25,10 @@ class UniqueValidator:
self.message = message or self.message
def set_context(self, serializer_field):
"""
This hook is called by the serializer instance,
prior to the validation call being made.
"""
# 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]
......@@ -54,6 +58,7 @@ class UniqueTogetherValidator:
Should be applied to the serializer class, not to an individual field.
"""
message = _('The fields {field_names} must make a unique set.')
missing_message = _('This field is required.')
def __init__(self, queryset, fields, message=None):
self.queryset = queryset
......@@ -62,17 +67,49 @@ class UniqueTogetherValidator:
self.message = message or self.message
def set_context(self, serializer):
"""
This hook is called by the serializer instance,
prior to the validation call being made.
"""
# Determine the existing instance, if this is an update operation.
self.instance = getattr(serializer, 'instance', None)
def __call__(self, attrs):
# Ensure uniqueness.
def enforce_required_fields(self, attrs):
"""
The `UniqueTogetherValidator` always forces an implied 'required'
state on the fields it applies to.
"""
missing = dict([
(field_name, self.missing_message)
for field_name in self.fields
if field_name not in attrs
])
if missing:
raise ValidationError(missing)
def filter_queryset(self, attrs, queryset):
"""
Filter the queryset to all instances matching the given attributes.
"""
filter_kwargs = dict([
(field_name, attrs[field_name]) for field_name in self.fields
])
queryset = self.queryset.filter(**filter_kwargs)
return queryset.filter(**filter_kwargs)
def exclude_current_instance(self, attrs, queryset):
"""
If an instance is being updated, then do not include
that instance itself as a uniqueness conflict.
"""
if self.instance is not None:
queryset = queryset.exclude(pk=self.instance.pk)
return queryset.exclude(pk=self.instance.pk)
return queryset
def __call__(self, attrs):
self.enforce_required_fields(attrs)
queryset = self.queryset
queryset = self.filter_queryset(attrs, queryset)
queryset = self.exclude_current_instance(attrs, queryset)
if queryset.exists():
field_names = ', '.join(self.fields)
raise ValidationError(self.message.format(field_names=field_names))
......@@ -87,6 +124,7 @@ class UniqueTogetherValidator:
class BaseUniqueForValidator:
message = None
missing_message = _('This field is required.')
def __init__(self, queryset, field, date_field, message=None):
self.queryset = queryset
......@@ -95,6 +133,10 @@ class BaseUniqueForValidator:
self.message = message or self.message
def set_context(self, serializer):
"""
This hook is called by the serializer instance,
prior to the validation call being made.
"""
# 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]
......@@ -102,15 +144,36 @@ class BaseUniqueForValidator:
# 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 enforce_required_fields(self, attrs):
"""
The `UniqueFor<Range>Validator` classes always force an implied
'required' state on the fields they are applied to.
"""
missing = dict([
(field_name, self.missing_message)
for field_name in [self.field, self.date_field]
if field_name not in attrs
])
if missing:
raise ValidationError(missing)
def __call__(self, attrs):
filter_kwargs = self.get_filter_kwargs(attrs)
def filter_queryset(self, attrs, queryset):
raise NotImplementedError('`filter_queryset` must be implemented.')
queryset = self.queryset.filter(**filter_kwargs)
def exclude_current_instance(self, attrs, queryset):
"""
If an instance is being updated, then do not include
that instance itself as a uniqueness conflict.
"""
if self.instance is not None:
queryset = queryset.exclude(pk=self.instance.pk)
return queryset.exclude(pk=self.instance.pk)
return queryset
def __call__(self, attrs):
self.enforce_required_fields(attrs)
queryset = self.queryset
queryset = self.filter_queryset(attrs, queryset)
queryset = self.exclude_current_instance(attrs, queryset)
if queryset.exists():
message = self.message.format(date_field=self.date_field)
raise ValidationError({self.field: message})
......@@ -127,7 +190,7 @@ class BaseUniqueForValidator:
class UniqueForDateValidator(BaseUniqueForValidator):
message = _('This field must be unique for the "{date_field}" date.')
def get_filter_kwargs(self, attrs):
def filter_queryset(self, attrs, queryset):
value = attrs[self.field]
date = attrs[self.date_field]
......@@ -136,30 +199,30 @@ class UniqueForDateValidator(BaseUniqueForValidator):
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
return queryset.filter(**filter_kwargs)
class UniqueForMonthValidator(BaseUniqueForValidator):
message = _('This field must be unique for the "{date_field}" month.')
def get_filter_kwargs(self, attrs):
def filter_queryset(self, attrs, queryset):
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
return queryset.filter(**filter_kwargs)
class UniqueForYearValidator(BaseUniqueForValidator):
message = _('This field must be unique for the "{date_field}" year.')
def get_filter_kwargs(self, attrs):
def filter_queryset(self, attrs, queryset):
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
return queryset.filter(**filter_kwargs)
tests/test_validators.py
......@@ -134,6 +134,17 @@ class TestUniquenessTogetherValidation(TestCase):
'position': 1
}
def test_unique_together_is_required(self):
"""
In a unique together validation, all fields are required.
"""
data = {'position': 2}
serializer = UniquenessTogetherSerializer(data=data, partial=True)
assert not serializer.is_valid()
assert serializer.errors == {
'race_name': ['This field is required.']
}
def test_ignore_excluded_fields(self):
"""
When model fields are not included in a serializer, then uniqueness
......
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