def get_fields(self):
fields = super(HyperlinkedModelSerializer, self).get_fields()
if api_settings.URL_FIELD_NAME in fields:
# replace HyperlinkedIdentityField with one that's namespaceable
fields[api_settings.URL_FIELD_NAME] = HyperlinkedIdentityField(
help_text="object detail API URL",
**get_url_kwargs(getattr(self.Meta, 'model')))
return fields
class ArticleSerializer(serializers.HyperlinkedModelSerializer):
url = serializers.HyperlinkedIdentityField(**get_url_kwargs(Article))
original_url = serializers.CharField(source='url')
class Meta:
model = Article
fields = (
'url',
'original_url',
'source',
'title',
'title_keywords',
'categories',
'retrieved_date',
'modified_date',
'original_post_date',
)
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