diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py index 43c7972a4..d21e92203 100644 --- a/rest_framework/serializers.py +++ b/rest_framework/serializers.py @@ -901,6 +901,136 @@ class ModelSerializer(Serializer): # "HTTP 201 Created" responses. url_field_name = None + def __init__(self, *args, **kwargs): + kwargs.pop('meta_fields', None) + kwargs.pop('meta_exclude', None) + kwargs.pop('meta_preset', None) + super(ModelSerializer, self).__init__(*args, **kwargs) + + def __new__(cls, *args, **kwargs): + if 'meta_fields' in kwargs: + fields = kwargs.pop('meta_fields') + if fields == '__all__': + fields = [] + return cls.meta_fields(*fields)(*args, **kwargs) + if 'meta_exclude' in kwargs: + return cls.meta_exclude(*kwargs.pop('meta_exclude'))(*args, **kwargs) + if 'meta_preset' in kwargs: + return cls.meta_preset(kwargs.pop('meta_preset'))(*args, **kwargs) + return super(ModelSerializer, cls).__new__(cls, *args, **kwargs) + + @classmethod + def meta_fields(cls, *fields): + """ + Create new class based on the current with overrode Meta parameters. + Option `exclude` of base serializer is going to None. + + Example of usage in serializers: + class UserSerializer(serializers.ModelSerializer): + class Meta: + model = User + + class ItemSerializer(serializers.ModelSerializer): + user = UserSerializer(meta_fields=['id', 'name']) + + class Meta: + model = Item + + Example of usage in views: + class UserViewSet(viewsets.ModelViewSet): + serializer_class = UserSerializer.meta_fields('id', 'name', 'expiration_date') + """ + if not len(fields): + fields = '__all__' + meta = getattr(cls, 'Meta', type('Meta', (), {})) + return type(cls.__name__, (cls,), { + 'Meta': type('Meta', (meta,), { + 'fields': fields, + 'exclude': None + }) + }) + + @classmethod + def meta_exclude(cls, *exclude): + """ + Create new class based on the current with overrode Meta parameters. + If base serializer has meta option `fields`, fields will exclude from its. + + Example of usage in serializers: + class UserSerializer(serializers.ModelSerializer): + products = ProductsSerializer(many=True) + + class Meta: + model = User + + class ItemSerializer(serializers.ModelSerializer): + user = UserSerializer(meta_exclude=['products']) + + class Meta: + model = Item + + Example of usage in views: + class UserViewSet(viewsets.ModelViewSet): + serializer_class = UserSerializer.meta_exclude('products') + """ + meta = getattr(cls, 'Meta', type('Meta', (), {})) + meta_fields = getattr(meta, 'fields', None) + exclude_props = [] + if isinstance(meta_fields, list) or isinstance(meta_fields, tuple): + meta_fields = [field_ for field_ in meta_fields if field_ not in exclude] + exclude = None + else: + meta_fields = None + exclude_props = [key for key, prop in cls._declared_fields.items() if isinstance(prop, Field)] + exclude = list(filter(lambda f: f not in exclude_props, exclude)) + return type(cls.__name__, (cls,), { + 'Meta': type('Meta', (meta,), { + 'fields': meta_fields, + 'exclude': exclude + }), + **{field: None for field in exclude_props} + }) + + @classmethod + def meta_preset(cls, name): + """ + Create new class based on the current with overrode Meta parameters. + It will check meta option `presets` and try to get it by name. + Presets - prepared some schemes, which simplify manipulating with meta option. + + Example of usage in serializers: + class UserSerializer(serializers.ModelSerializer): + products = ProductsSerializer(many=True) + + class Meta: + model = User + presets = { + 'short': { + 'fields': ['id', 'name'] + }, + 'light': { + 'exclude': ['products'] + } + } + + class ItemSerializer(serializers.ModelSerializer): + user = UserSerializer(meta_preset='short') + + class Meta: + model = Item + + Example of usage in views: + class UserViewSet(viewsets.ModelViewSet): + serializer_class = UserSerializer.meta_preset('light') + """ + meta = getattr(cls, 'Meta', type('Meta', (), {})) + presets = getattr(meta, 'presets', {}) + preset = presets.get(name, None) + assert preset is not None, ('Preset of `%s` with `%s` name doesn\'t exist.' % (cls.__name__, name)) + return type(cls.__name__, (cls,), { + 'Meta': type('Meta', (meta,), preset) + }) + # Default `create` and `update` behavior... def create(self, validated_data): """