diff options
Diffstat (limited to 'rest_framework/serializers.py')
| -rw-r--r-- | rest_framework/serializers.py | 678 |
1 files changed, 442 insertions, 236 deletions
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py index e373cd10..77d3f202 100644 --- a/rest_framework/serializers.py +++ b/rest_framework/serializers.py @@ -327,7 +327,9 @@ class Serializer(BaseSerializer): Returns a list of validator callables. """ # Used by the lazily-evaluated `validators` property. - return getattr(getattr(self, 'Meta', None), 'validators', []) + meta = getattr(self, 'Meta', None) + validators = getattr(meta, 'validators', None) + return validators[:] if validators else [] def get_initial(self): if hasattr(self, 'initial_data'): @@ -477,7 +479,7 @@ class ListSerializer(BaseSerializer): many = True default_error_messages = { - 'not_a_list': _('Expected a list of items but got type `{input_type}`.') + 'not_a_list': _('Expected a list of items but got type "{input_type}".') } def __init__(self, *args, **kwargs): @@ -702,7 +704,7 @@ class ModelSerializer(Serializer): you need you should either declare the extra/differing fields explicitly on the serializer class, or simply use a `Serializer` class. """ - _field_mapping = ClassLookupDict({ + serializer_field_mapping = { models.AutoField: IntegerField, models.BigIntegerField: IntegerField, models.BooleanField: BooleanField, @@ -725,8 +727,10 @@ class ModelSerializer(Serializer): models.TextField: CharField, models.TimeField: TimeField, models.URLField: URLField, - }) - _related_class = PrimaryKeyRelatedField + } + serializer_related_class = PrimaryKeyRelatedField + + # Default `create` and `update` behavior... def create(self, validated_data): """ @@ -797,69 +801,81 @@ class ModelSerializer(Serializer): return instance - def get_validators(self): - # If the validators have been declared explicitly then use that. - validators = getattr(getattr(self, 'Meta', None), 'validators', None) - if validators is not None: - return validators + # Determine the fields to apply... - # Determine the default set of validators. - validators = [] - model_class = self.Meta.model - field_names = set([ - field.source for field in self.fields.values() - if (field.source != '*') and ('.' not in field.source) - ]) + def get_fields(self): + """ + Return the dict of field names -> field instances that should be + used for `self.fields` when instantiating the serializer. + """ + assert hasattr(self, 'Meta'), ( + 'Class {serializer_class} missing "Meta" attribute'.format( + serializer_class=self.__class__.__name__ + ) + ) + assert hasattr(self.Meta, 'model'), ( + 'Class {serializer_class} missing "Meta.model" attribute'.format( + serializer_class=self.__class__.__name__ + ) + ) - # Note that we make sure to check `unique_together` both on the - # base model class, but also on any parent classes. - for parent_class in [model_class] + list(model_class._meta.parents.keys()): - for unique_together in parent_class._meta.unique_together: - if field_names.issuperset(set(unique_together)): - validator = UniqueTogetherValidator( - queryset=parent_class._default_manager, - fields=unique_together - ) - validators.append(validator) + declared_fields = copy.deepcopy(self._declared_fields) + model = getattr(self.Meta, 'model') + depth = getattr(self.Meta, 'depth', 0) - # Add any unique_for_date/unique_for_month/unique_for_year constraints. - info = model_meta.get_field_info(model_class) - for field_name, field in info.fields_and_pk.items(): - if field.unique_for_date and field_name in field_names: - validator = UniqueForDateValidator( - queryset=model_class._default_manager, - field=field_name, - date_field=field.unique_for_date - ) - validators.append(validator) + if depth is not None: + assert depth >= 0, "'depth' may not be negative." + assert depth <= 10, "'depth' may not be greater than 10." - if field.unique_for_month and field_name in field_names: - validator = UniqueForMonthValidator( - queryset=model_class._default_manager, - field=field_name, - date_field=field.unique_for_month - ) - validators.append(validator) + # Retrieve metadata about fields & relationships on the model class. + info = model_meta.get_field_info(model) + field_names = self.get_field_names(declared_fields, info) - if field.unique_for_year and field_name in field_names: - validator = UniqueForYearValidator( - queryset=model_class._default_manager, - field=field_name, - date_field=field.unique_for_year - ) - validators.append(validator) + # Determine any extra field arguments and hidden fields that + # should be included + extra_kwargs = self.get_extra_kwargs() + extra_kwargs, hidden_fields = self.get_uniqueness_extra_kwargs( + field_names, declared_fields, extra_kwargs + ) - return validators + # Determine the fields that should be included on the serializer. + fields = OrderedDict() - def get_fields(self): - declared_fields = copy.deepcopy(self._declared_fields) + for field_name in field_names: + # If the field is explicitly declared on the class then use that. + if field_name in declared_fields: + fields[field_name] = declared_fields[field_name] + continue - ret = OrderedDict() - model = getattr(self.Meta, 'model') + # Determine the serializer field class and keyword arguments. + field_class, field_kwargs = self.build_field( + field_name, info, model, depth + ) + + # Include any kwargs defined in `Meta.extra_kwargs` + field_kwargs = self.build_field_kwargs( + field_kwargs, extra_kwargs, field_name + ) + + # Create the serializer field. + fields[field_name] = field_class(**field_kwargs) + + # Add in any hidden fields. + fields.update(hidden_fields) + + return fields + + # Methods for determining the set of field names to include... + + def get_field_names(self, declared_fields, info): + """ + Returns the list of all field names that should be created when + instantiating this serializer class. This is based on the default + set of fields, but also takes into account the `Meta.fields` or + `Meta.exclude` options if they have been specified. + """ 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', {}) if fields and not isinstance(fields, (list, tuple)): raise TypeError( @@ -873,192 +889,191 @@ class ModelSerializer(Serializer): type(exclude).__name__ ) - assert not (fields and exclude), "Cannot set both 'fields' and 'exclude'." + assert not (fields and exclude), ( + "Cannot set both 'fields' and 'exclude' options on " + "serializer {serializer_class}.".format( + serializer_class=self.__class__.__name__ + ) + ) - extra_kwargs = self._include_additional_options(extra_kwargs) + if fields is not None: + # Ensure that all declared fields have also been included in the + # `Meta.fields` option. + for field_name in declared_fields: + assert field_name in fields, ( + "The field '{field_name}' was declared on serializer " + "{serializer_class}, but has not been included in the " + "'fields' option.".format( + field_name=field_name, + serializer_class=self.__class__.__name__ + ) + ) + return fields + + # Use the default set of field names if `Meta.fields` is not specified. + fields = self.get_default_field_names(declared_fields, info) + + if exclude is not None: + # If `Meta.exclude` is included, then remove those fields. + for field_name in exclude: + assert field_name in fields, ( + "The field '{field_name}' was include on serializer " + "{serializer_class} in the 'exclude' option, but does " + "not match any model field.".format( + field_name=field_name, + serializer_class=self.__class__.__name__ + ) + ) + fields.remove(field_name) - # Retrieve metadata about fields & relationships on the model class. - info = model_meta.get_field_info(model) + return fields - # 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: - assert field_name in fields, ( - 'The field in the `exclude` option must be a model field. Got %s.' % - field_name - ) - fields.remove(field_name) + def get_default_field_names(self, declared_fields, model_info): + """ + Return the default list of field names that will be used if the + `Meta.fields` option is not specified. + """ + return ( + [model_info.pk.name] + + list(declared_fields.keys()) + + list(model_info.fields.keys()) + + list(model_info.forward_relations.keys()) + ) - # 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 + # Methods for constructing serializer fields... + + def build_field(self, field_name, info, model_class, nested_depth): + """ + Return a two tuple of (cls, kwargs) to build a serializer field with. + """ + if field_name in info.fields_and_pk: + model_field = info.fields_and_pk[field_name] + return self.build_standard_field(field_name, model_field) + + elif field_name in info.relations: + relation_info = info.relations[field_name] + if not nested_depth: + return self.build_relational_field(field_name, relation_info) 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 + return self.build_nested_field(field_name, relation_info, nested_depth) - # 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() + elif hasattr(model_class, field_name): + return self.build_property_field(field_name, model_class) - for model_field_name, field_name in model_field_mapping.items(): - try: - model_field = model._meta.get_field(model_field_name) - except FieldDoesNotExist: - continue + elif field_name == api_settings.URL_FIELD_NAME: + return self.build_url_field(field_name, model_class) - # 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 - ]) + return self.build_unknown_field(field_name, model_class) - unique_constraint_names -= set([None]) + def build_standard_field(self, field_name, model_field): + """ + Create regular model fields. + """ + field_mapping = ClassLookupDict(self.serializer_field_mapping) + + field_class = field_mapping[model_field] + field_kwargs = get_field_kwargs(field_name, model_field) + + if 'choices' in field_kwargs: + # Fields with choices get coerced into `ChoiceField` + # instead of using their regular typed field. + field_class = ChoiceField + if not issubclass(field_class, 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. + field_kwargs.pop('model_field', None) + if not issubclass(field_class, CharField) and not issubclass(field_class, ChoiceField): + # `allow_blank` is only valid for textual fields. + field_kwargs.pop('allow_blank', None) + + return field_class, field_kwargs + + def build_relational_field(self, field_name, relation_info): + """ + Create fields for forward and reverse relationships. + """ + field_class = self.serializer_related_class + field_kwargs = get_relation_kwargs(field_name, relation_info) - # 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) + # `view_name` is only valid for hyperlinked relationships. + if not issubclass(field_class, HyperlinkedRelatedField): + field_kwargs.pop('view_name', None) - # 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 referred too. - unique_constraint_field = model._meta.get_field(unique_constraint_name) + return field_class, field_kwargs - 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 + def build_nested_field(self, field_name, relation_info, nested_depth): + """ + Create nested fields for forward and reverse relationships. + """ + class NestedSerializer(ModelSerializer): + class Meta: + model = relation_info.related_model + depth = nested_depth - 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) + field_class = NestedSerializer + field_kwargs = get_nested_relation_kwargs(relation_info) - # 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 + return field_class, field_kwargs - 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) and not issubclass(field_cls, ChoiceField): - # `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) + def build_property_field(self, field_name, model_class): + """ + Create a read only field for model methods and properties. + """ + field_class = ReadOnlyField + field_kwargs = {} - else: - raise ImproperlyConfigured( - 'Field name `%s` is not valid for model `%s`.' % - (field_name, model.__class__.__name__) - ) + return field_class, field_kwargs - # Check that any fields declared on the class are - # also explicitly 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__) - ) + def build_url_field(self, field_name, model_class): + """ + Create a field representing the object's own URL. + """ + field_class = HyperlinkedIdentityField + field_kwargs = get_url_kwargs(model_class) - # 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) + return field_class, field_kwargs - if extras.get('default') and kwargs.get('required') is False: - kwargs.pop('required') + def build_unknown_field(self, field_name, model_class): + """ + Raise an error on any unknown fields. + """ + raise ImproperlyConfigured( + 'Field name `%s` is not valid for model `%s`.' % + (field_name, model_class.__name__) + ) + + def build_field_kwargs(self, kwargs, extra_kwargs, field_name): + """ + Include an 'extra_kwargs' that have been included for this field, + possibly removing any incompatible existing keyword arguments. + """ + extras = extra_kwargs.get(field_name, {}) - kwargs.update(extras) + 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) - # Create the serializer field. - ret[field_name] = field_cls(**kwargs) + if extras.get('default') and kwargs.get('required') is False: + kwargs.pop('required') - for field_name, field in hidden_fields.items(): - ret[field_name] = field + kwargs.update(extras) - return ret + return kwargs + + # Methods for determining additional keyword arguments to apply... + + def get_extra_kwargs(self): + """ + Return a dictionary mapping field names to a dictionary of + additional keyword arguments. + """ + extra_kwargs = getattr(self.Meta, 'extra_kwargs', {}) - def _include_additional_options(self, extra_kwargs): read_only_fields = getattr(self.Meta, 'read_only_fields', None) if read_only_fields is not None: for field_name in read_only_fields: @@ -1106,21 +1121,202 @@ class ModelSerializer(Serializer): return extra_kwargs - def _get_default_field_names(self, declared_fields, model_info): + def get_uniqueness_extra_kwargs(self, field_names, declared_fields, extra_kwargs): + """ + Return any additional field options that need to be included as a + result of uniqueness constraints on the model. This is returned as + a two-tuple of: + + ('dict of updated extra kwargs', 'mapping of hidden fields') + """ + model = getattr(self.Meta, 'model') + model_fields = self._get_model_fields( + field_names, declared_fields, extra_kwargs + ) + + # 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. + unique_constraint_names = set() + + for model_field in model_fields.values(): + # 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(field_names).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. + hidden_fields = {} + uniqueness_extra_kwargs = {} + + for unique_constraint_name in unique_constraint_names: + # Get the model field that is referred 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_fields: + # The corresponding field is present in the serializer + if default is empty: + uniqueness_extra_kwargs[unique_constraint_name] = {'required': True} + else: + uniqueness_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) + + # Update `extra_kwargs` with any new options. + for key, value in uniqueness_extra_kwargs.items(): + if key in extra_kwargs: + extra_kwargs[key].update(value) + else: + extra_kwargs[key] = value + + return extra_kwargs, hidden_fields + + def _get_model_fields(self, field_names, declared_fields, extra_kwargs): + """ + Returns all the model fields that are being mapped to by fields + on the serializer class. + Returned as a dict of 'model field name' -> 'model field'. + Used internally by `get_uniqueness_field_options`. + """ + model = getattr(self.Meta, 'model') + model_fields = {} + + for field_name in field_names: + if field_name in declared_fields: + # If the field is declared on the serializer + field = declared_fields[field_name] + source = field.source or field_name + else: + try: + source = extra_kwargs[field_name]['source'] + except KeyError: + source = field_name + + if '.' in source or source == '*': + # Model fields will always have a simple source mapping, + # they can't be nested attribute lookups. + continue + + try: + model_fields[source] = model._meta.get_field(source) + except FieldDoesNotExist: + pass + + return model_fields + + # Determine the validators to apply... + + def get_validators(self): + """ + Determine the set of validators to use when instantiating serializer. + """ + # If the validators have been declared explicitly then use that. + validators = getattr(getattr(self, 'Meta', None), 'validators', None) + if validators is not None: + return validators[:] + + # Otherwise use the default set of validators. return ( - [model_info.pk.name] + - list(declared_fields.keys()) + - list(model_info.fields.keys()) + - list(model_info.forward_relations.keys()) + self.get_unique_together_validators() + + self.get_unique_for_date_validators() ) - def _get_nested_class(self, nested_depth, relation_info): - class NestedSerializer(ModelSerializer): - class Meta: - model = relation_info.related - depth = nested_depth - 1 + def get_unique_together_validators(self): + """ + Determine a default set of validators for any unique_together contraints. + """ + model_class_inheritance_tree = ( + [self.Meta.model] + + list(self.Meta.model._meta.parents.keys()) + ) - return NestedSerializer + # The field names we're passing though here only include fields + # which may map onto a model field. Any dotted field name lookups + # cannot map to a field, and must be a traversal, so we're not + # including those. + field_names = set([ + field.source for field in self.fields.values() + if (field.source != '*') and ('.' not in field.source) + ]) + + # Note that we make sure to check `unique_together` both on the + # base model class, but also on any parent classes. + validators = [] + for parent_class in model_class_inheritance_tree: + for unique_together in parent_class._meta.unique_together: + if field_names.issuperset(set(unique_together)): + validator = UniqueTogetherValidator( + queryset=parent_class._default_manager, + fields=unique_together + ) + validators.append(validator) + return validators + + def get_unique_for_date_validators(self): + """ + Determine a default set of validators for the following contraints: + + * unique_for_date + * unique_for_month + * unique_for_year + """ + info = model_meta.get_field_info(self.Meta.model) + default_manager = self.Meta.model._default_manager + field_names = [field.source for field in self.fields.values()] + + validators = [] + + for field_name, field in info.fields_and_pk.items(): + if field.unique_for_date and field_name in field_names: + validator = UniqueForDateValidator( + queryset=default_manager, + field=field_name, + date_field=field.unique_for_date + ) + validators.append(validator) + + if field.unique_for_month and field_name in field_names: + validator = UniqueForMonthValidator( + queryset=default_manager, + field=field_name, + date_field=field.unique_for_month + ) + validators.append(validator) + + if field.unique_for_year and field_name in field_names: + validator = UniqueForYearValidator( + queryset=default_manager, + field=field_name, + date_field=field.unique_for_year + ) + validators.append(validator) + + return validators class HyperlinkedModelSerializer(ModelSerializer): @@ -1131,9 +1327,13 @@ class HyperlinkedModelSerializer(ModelSerializer): * A 'url' field is included instead of the 'id' field. * Relationships to other instances are hyperlinks, instead of primary keys. """ - _related_class = HyperlinkedRelatedField + serializer_related_class = HyperlinkedRelatedField - def _get_default_field_names(self, declared_fields, model_info): + def get_default_field_names(self, declared_fields, model_info): + """ + Return the default list of field names that will be used if the + `Meta.fields` option is not specified. + """ return ( [api_settings.URL_FIELD_NAME] + list(declared_fields.keys()) + @@ -1141,10 +1341,16 @@ class HyperlinkedModelSerializer(ModelSerializer): list(model_info.forward_relations.keys()) ) - def _get_nested_class(self, nested_depth, relation_info): + def build_nested_field(self, field_name, relation_info, nested_depth): + """ + Create nested fields for forward and reverse relationships. + """ class NestedSerializer(HyperlinkedModelSerializer): class Meta: - model = relation_info.related + model = relation_info.related_model depth = nested_depth - 1 - return NestedSerializer + field_class = NestedSerializer + field_kwargs = get_nested_relation_kwargs(relation_info) + + return field_class, field_kwargs |