def build_standard_field(self, field_name, model_field):
"""
By default `ModelSerializer.build_standard_field` coerces any field
that has a model field with choices to `ChoiceField` wich returns the
value directly.
Since enum values resemble `EnumClass.ENUM_INSTANCE`
they won't be able to be encoded by the JSONEncoder when being passed
to a `Response`.
"""
if isinstance(model_field, ModelEnumChoiceField):
# These are kwargs, generated by `get_field_kwargs`
# but are not needed for our field.
# `model_field` is used only in children of DRF's `ModelField`
# `choices` is not used because we use `field.enum_class` to validate the choice
# `max_length` is generated from the model field's max_length and we don't use it
dump_kwargs = ('model_field', 'choices', 'max_length')
initial_kwargs = {
'enum_class': model_field.enum_class,
'choice_builder': model_field.choice_builder,
**get_field_kwargs(field_name, model_field)
}
finalized_kwargs = {
key: value for key, value in initial_kwargs.items()
if key not in dump_kwargs
}
return EnumChoiceField, finalized_kwargs
return super().build_standard_field(field_name, model_field)
def _get_default_field_kwargs(model, field):
"""
Get the required attributes from the model field in order
to instantiate a REST Framework serializer field.
"""
kwargs = {}
try:
field_name = field.model_attr or field.index_fieldname
model_field = model._meta.get_field(field_name)
kwargs.update(get_field_kwargs(field_name, model_field))
# Remove stuff we don't care about!
delete_attrs = [
"allow_blank",
"choices",
"model_field",
"allow_unicode",
]
for attr in delete_attrs:
if attr in kwargs:
del kwargs[attr]
except FieldDoesNotExist:
pass
return kwargs
def _get_default_field_kwargs(model, field):
"""
Get the required attributes from the model field in order
to instantiate a REST Framework serializer field.
"""
kwargs = {}
try:
field_name = field.model_attr or field.index_fieldname
model_field = model._meta.get_field(field_name)
kwargs.update(get_field_kwargs(field_name, model_field))
# Remove stuff we don't care about!
delete_attrs = [
"allow_blank",
"choices",
"model_field",
"allow_unicode",
]
for attr in delete_attrs:
if attr in kwargs:
del kwargs[attr]
except FieldDoesNotExist:
pass
return kwargs
def get_polymorphic_fields(self):
"""
returns a dictionary of {field_name: field_instance} for polymorphic
fields.
"""
if not self.polymorphic_class_mapping:
self._build_polymorphic_field_mapping()
polymorphic_fields = OrderedDict()
try:
field_mapping = self._field_mapping
except AttributeError:
field_mapping = ClassLookupDict(self.serializer_field_mapping)
for _, subclass in six.iteritems(self.polymorphic_class_mapping):
for field in subclass.fields:
rest_field = field_mapping[field]
kwargs = get_field_kwargs(field.name, field)
if 'choices' in kwargs:
rest_field = serializers.ChoiceField
if not issubclass(rest_field, serializers.ModelField):
kwargs.pop('model_field', None)
if (not issubclass(rest_field, serializers.CharField) and
not issubclass(rest_field, serializers.ChoiceField)):
kwargs.pop('allow_blank', None)
polymorphic_fields[field.name] = rest_field(**kwargs)
return polymorphic_fields
def get_polymorphic_fields(self):
"""
returns a dictionary of {field_name: field_instance} for polymorphic
fields.
"""
if not self.polymorphic_class_mapping:
self._build_polymorphic_field_mapping()
polymorphic_fields = OrderedDict()
try:
field_mapping = self._field_mapping
except AttributeError:
field_mapping = ClassLookupDict(self.serializer_field_mapping)
for _, subclass in six.iteritems(self.polymorphic_class_mapping):
for field in subclass.fields:
rest_field = field_mapping[field]
kwargs = get_field_kwargs(field.name, field)
if 'choices' in kwargs:
rest_field = serializers.ChoiceField
if not issubclass(rest_field, serializers.ModelField):
kwargs.pop('model_field', None)
if (not issubclass(rest_field, serializers.CharField) and
not issubclass(rest_field, serializers.ChoiceField)):
kwargs.pop('allow_blank', None)
polymorphic_fields[field.name] = rest_field(**kwargs)
return polymorphic_fields
def _get_default_field_kwargs(model, field):
"""
Get the required attributes from the model field in order
to instantiate a REST Framework serializer field.
"""
kwargs = {}
if field.model_attr in model._meta.get_all_field_names():
model_field = model._meta.get_field_by_name(field.model_attr)[0]
kwargs = get_field_kwargs(field.model_attr, model_field)
# Remove stuff we don't care about!
delete_attrs = [
"model_field",
"choices"
]
for attr in delete_attrs:
if attr in kwargs:
del kwargs[attr]
return kwargs
def _get_default_field_kwargs(model, field):
"""
Get the required attributes from the model field in order
to instantiate a REST Framework serializer field.
"""
kwargs = {}
if field.model_attr in model._meta.get_fields():
model_field = model._meta.get_field(field.model_attr)[0]
kwargs = get_field_kwargs(field.model_attr, model_field)
# Remove stuff we don't care about!
delete_attrs = [
"allow_blank",
"choices",
"model_field",
]
for attr in delete_attrs:
if attr in kwargs:
del kwargs[attr]
return kwargs
def get_fields(self):
declared_fields = copy.deepcopy(self._declared_fields)
ret = OrderedDict()
model = getattr(self.Meta, 'model')
fields = getattr(self.Meta, 'fields', None)
exclude = getattr(self.Meta, 'exclude', None)
depth = getattr(self.Meta, 'depth', 0)
extra_kwargs = getattr(self.Meta, 'extra_kwargs', {})
assert not (fields and exclude), "Cannot set both 'fields' and 'exclude'."
extra_kwargs = self._include_additional_options(extra_kwargs)
# Retrieve metadata about fields & relationships on the model class.
info = model_meta.get_field_info(model)
# Use the default set of field names if none is supplied explicitly.
if fields is None:
fields = self._get_default_field_names(declared_fields, info)
exclude = getattr(self.Meta, 'exclude', None)
if exclude is not None:
for field_name in exclude:
fields.remove(field_name)
# Determine the set of model fields, and the fields that they map to.
# We actually only need this to deal with the slightly awkward case
# of supporting `unique_for_date`/`unique_for_month`/`unique_for_year`.
model_field_mapping = {}
for field_name in fields:
if field_name in declared_fields:
field = declared_fields[field_name]
source = field.source or field_name
else:
try:
source = extra_kwargs[field_name]['source']
except KeyError:
source = field_name
# Model fields will always have a simple source mapping,
# they can't be nested attribute lookups.
if '.' not in source and source != '*':
model_field_mapping[source] = field_name
# Determine if we need any additional `HiddenField` or extra keyword
# arguments to deal with `unique_for` dates that are required to
# be in the input data in order to validate it.
hidden_fields = {}
unique_constraint_names = set()
for model_field_name, field_name in model_field_mapping.items():
try:
model_field = model._meta.get_field(model_field_name)
except FieldDoesNotExist:
continue
# Include each of the `unique_for_*` field names.
unique_constraint_names |= set([
model_field.unique_for_date,
model_field.unique_for_month,
model_field.unique_for_year
])
unique_constraint_names -= set([None])
# Include each of the `unique_together` field names,
# so long as all the field names are included on the serializer.
for parent_class in [model] + list(model._meta.parents.keys()):
for unique_together_list in parent_class._meta.unique_together:
if set(fields).issuperset(set(unique_together_list)):
unique_constraint_names |= set(unique_together_list)
# Now we have all the field names that have uniqueness constraints
# applied, we can add the extra 'required=...' or 'default=...'
# arguments that are appropriate to these fields, or add a `HiddenField` for it.
for unique_constraint_name in unique_constraint_names:
# Get the model field that is refered too.
unique_constraint_field = model._meta.get_field(unique_constraint_name)
if getattr(unique_constraint_field, 'auto_now_add', None):
default = CreateOnlyDefault(timezone.now)
elif getattr(unique_constraint_field, 'auto_now', None):
default = timezone.now
elif unique_constraint_field.has_default():
default = unique_constraint_field.default
else:
default = empty
if unique_constraint_name in model_field_mapping:
# The corresponding field is present in the serializer
if unique_constraint_name not in extra_kwargs:
extra_kwargs[unique_constraint_name] = {}
if default is empty:
if 'required' not in extra_kwargs[unique_constraint_name]:
extra_kwargs[unique_constraint_name]['required'] = True
else:
if 'default' not in extra_kwargs[unique_constraint_name]:
extra_kwargs[unique_constraint_name]['default'] = default
elif default is not empty:
# The corresponding field is not present in the,
# serializer. We have a default to use for it, so
# add in a hidden field that populates it.
hidden_fields[unique_constraint_name] = HiddenField(default=default)
# Now determine the fields that should be included on the serializer.
for field_name in fields:
if field_name in declared_fields:
# Field is explicitly declared on the class, use that.
ret[field_name] = declared_fields[field_name]
continue
elif field_name in info.fields_and_pk:
# Create regular model fields.
model_field = info.fields_and_pk[field_name]
field_cls = self._field_mapping[model_field]
kwargs = get_field_kwargs(field_name, model_field)
if 'choices' in kwargs:
# Fields with choices get coerced into `ChoiceField`
# instead of using their regular typed field.
field_cls = ChoiceField
if not issubclass(field_cls, ModelField):
# `model_field` is only valid for the fallback case of
# `ModelField`, which is used when no other typed field
# matched to the model field.
kwargs.pop('model_field', None)
if not issubclass(field_cls, CharField):
# `allow_blank` is only valid for textual fields.
kwargs.pop('allow_blank', None)
elif field_name in info.relations:
# Create forward and reverse relationships.
relation_info = info.relations[field_name]
if depth:
field_cls = self._get_nested_class(depth, relation_info)
kwargs = get_nested_relation_kwargs(relation_info)
else:
field_cls = self._related_class
kwargs = get_relation_kwargs(field_name, relation_info)
# `view_name` is only valid for hyperlinked relationships.
if not issubclass(field_cls, HyperlinkedRelatedField):
kwargs.pop('view_name', None)
elif hasattr(model, field_name):
# Create a read only field for model methods and properties.
field_cls = ReadOnlyField
kwargs = {}
elif field_name == api_settings.URL_FIELD_NAME:
# Create the URL field.
field_cls = HyperlinkedIdentityField
kwargs = get_url_kwargs(model)
else:
raise ImproperlyConfigured(
'Field name `%s` is not valid for model `%s`.' %
(field_name, model.__class__.__name__)
)
# Check that any fields declared on the class are
# also explicity included in `Meta.fields`.
missing_fields = set(declared_fields.keys()) - set(fields)
if missing_fields:
missing_field = list(missing_fields)[0]
raise ImproperlyConfigured(
'Field `%s` has been declared on serializer `%s`, but '
'is missing from `Meta.fields`.' %
(missing_field, self.__class__.__name__)
)
# Populate any kwargs defined in `Meta.extra_kwargs`
extras = extra_kwargs.get(field_name, {})
if extras.get('read_only', False):
for attr in [
'required', 'default', 'allow_blank', 'allow_null',
'min_length', 'max_length', 'min_value', 'max_value',
'validators', 'queryset'
]:
kwargs.pop(attr, None)
if extras.get('default') and kwargs.get('required') is False:
kwargs.pop('required')
kwargs.update(extras)
# Create the serializer field.
ret[field_name] = field_cls(**kwargs)
for field_name, field in hidden_fields.items():
ret[field_name] = field
return ret
def get_fields(self):
declared_fields = copy.deepcopy(self._declared_fields)
ret = OrderedDict()
model = getattr(self.Meta, 'model')
fields = getattr(self.Meta, 'fields', None)
exclude = getattr(self.Meta, 'exclude', None)
depth = getattr(self.Meta, 'depth', 0)
extra_kwargs = getattr(self.Meta, 'extra_kwargs', {})
assert not (fields and exclude), "Cannot set both 'fields' and 'exclude'."
extra_kwargs = self._include_additional_options(extra_kwargs)
# Retrieve metadata about fields & relationships on the model class.
info = model_meta.get_field_info(model)
# Use the default set of field names if none is supplied explicitly.
if fields is None:
fields = self._get_default_field_names(declared_fields, info)
exclude = getattr(self.Meta, 'exclude', None)
if exclude is not None:
for field_name in exclude:
fields.remove(field_name)
# Determine the set of model fields, and the fields that they map to.
# We actually only need this to deal with the slightly awkward case
# of supporting `unique_for_date`/`unique_for_month`/`unique_for_year`.
model_field_mapping = {}
for field_name in fields:
if field_name in declared_fields:
field = declared_fields[field_name]
source = field.source or field_name
else:
try:
source = extra_kwargs[field_name]['source']
except KeyError:
source = field_name
# Model fields will always have a simple source mapping,
# they can't be nested attribute lookups.
if '.' not in source and source != '*':
model_field_mapping[source] = field_name
# Determine if we need any additional `HiddenField` or extra keyword
# arguments to deal with `unique_for` dates that are required to
# be in the input data in order to validate it.
hidden_fields = {}
unique_constraint_names = set()
for model_field_name, field_name in model_field_mapping.items():
try:
model_field = model._meta.get_field(model_field_name)
except FieldDoesNotExist:
continue
# Include each of the `unique_for_*` field names.
unique_constraint_names |= set([
model_field.unique_for_date,
model_field.unique_for_month,
model_field.unique_for_year
])
unique_constraint_names -= set([None])
# Include each of the `unique_together` field names,
# so long as all the field names are included on the serializer.
for parent_class in [model] + list(model._meta.parents.keys()):
for unique_together_list in parent_class._meta.unique_together:
if set(fields).issuperset(set(unique_together_list)):
unique_constraint_names |= set(unique_together_list)
# Now we have all the field names that have uniqueness constraints
# applied, we can add the extra 'required=...' or 'default=...'
# arguments that are appropriate to these fields, or add a `HiddenField` for it.
for unique_constraint_name in unique_constraint_names:
# Get the model field that is refered too.
unique_constraint_field = model._meta.get_field(unique_constraint_name)
if getattr(unique_constraint_field, 'auto_now_add', None):
default = CreateOnlyDefault(timezone.now)
elif getattr(unique_constraint_field, 'auto_now', None):
default = timezone.now
elif unique_constraint_field.has_default():
default = unique_constraint_field.default
else:
default = empty
if unique_constraint_name in model_field_mapping:
# The corresponding field is present in the serializer
if unique_constraint_name not in extra_kwargs:
extra_kwargs[unique_constraint_name] = {}
if default is empty:
if 'required' not in extra_kwargs[unique_constraint_name]:
extra_kwargs[unique_constraint_name]['required'] = True
else:
if 'default' not in extra_kwargs[unique_constraint_name]:
extra_kwargs[unique_constraint_name]['default'] = default
elif default is not empty:
# The corresponding field is not present in the,
# serializer. We have a default to use for it, so
# add in a hidden field that populates it.
hidden_fields[unique_constraint_name] = HiddenField(default=default)
# Now determine the fields that should be included on the serializer.
for field_name in fields:
if field_name in declared_fields:
# Field is explicitly declared on the class, use that.
ret[field_name] = declared_fields[field_name]
continue
elif field_name in info.fields_and_pk:
# Create regular model fields.
model_field = info.fields_and_pk[field_name]
field_cls = self._field_mapping[model_field]
kwargs = get_field_kwargs(field_name, model_field)
if 'choices' in kwargs:
# Fields with choices get coerced into `ChoiceField`
# instead of using their regular typed field.
field_cls = ChoiceField
if not issubclass(field_cls, ModelField):
# `model_field` is only valid for the fallback case of
# `ModelField`, which is used when no other typed field
# matched to the model field.
kwargs.pop('model_field', None)
if not issubclass(field_cls, CharField):
# `allow_blank` is only valid for textual fields.
kwargs.pop('allow_blank', None)
elif field_name in info.relations:
# Create forward and reverse relationships.
relation_info = info.relations[field_name]
if depth:
field_cls = self._get_nested_class(depth, relation_info)
kwargs = get_nested_relation_kwargs(relation_info)
else:
field_cls = self._related_class
kwargs = get_relation_kwargs(field_name, relation_info)
# `view_name` is only valid for hyperlinked relationships.
if not issubclass(field_cls, HyperlinkedRelatedField):
kwargs.pop('view_name', None)
elif hasattr(model, field_name):
# Create a read only field for model methods and properties.
field_cls = ReadOnlyField
kwargs = {}
elif field_name == api_settings.URL_FIELD_NAME:
# Create the URL field.
field_cls = HyperlinkedIdentityField
kwargs = get_url_kwargs(model)
else:
raise ImproperlyConfigured(
'Field name `%s` is not valid for model `%s`.' %
(field_name, model.__class__.__name__)
)
# Check that any fields declared on the class are
# also explicity included in `Meta.fields`.
missing_fields = set(declared_fields.keys()) - set(fields)
if missing_fields:
missing_field = list(missing_fields)[0]
raise ImproperlyConfigured(
'Field `%s` has been declared on serializer `%s`, but '
'is missing from `Meta.fields`.' %
(missing_field, self.__class__.__name__)
)
# Populate any kwargs defined in `Meta.extra_kwargs`
extras = extra_kwargs.get(field_name, {})
if extras.get('read_only', False):
for attr in [
'required', 'default', 'allow_blank', 'allow_null',
'min_length', 'max_length', 'min_value', 'max_value',
'validators', 'queryset'
]:
kwargs.pop(attr, None)
if extras.get('default') and kwargs.get('required') is False:
kwargs.pop('required')
kwargs.update(extras)
# Create the serializer field.
ret[field_name] = field_cls(**kwargs)
for field_name, field in hidden_fields.items():
ret[field_name] = field
return ret
