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| author | Tom Christie | 2012-10-30 14:32:31 +0000 |
|---|---|---|
| committer | Tom Christie | 2012-10-30 14:32:31 +0000 |
| commit | 9b30dab4f772f67a626e176dc4fae0a3ef9c2c81 (patch) | |
| tree | ca138abf4792f58ffa28684f784f201ee1eef6d7 /rest_framework/serializers.py | |
| parent | 7e5b1501b5cede61a9391fb1a751d2ebcdb37031 (diff) | |
| parent | 4e7805cb24d73e7f706318b5e5a27e3f9ba39d14 (diff) | |
| download | django-rest-framework-9b30dab4f772f67a626e176dc4fae0a3ef9c2c81.tar.bz2 | |
Merge branch 'restframework2' into rest-framework-2-merge2.0.0
Conflicts:
.gitignore
.travis.yml
AUTHORS
README.rst
djangorestframework/mixins.py
djangorestframework/renderers.py
djangorestframework/resources.py
djangorestframework/serializer.py
djangorestframework/templates/djangorestframework/base.html
djangorestframework/templates/djangorestframework/login.html
djangorestframework/templatetags/add_query_param.py
djangorestframework/tests/accept.py
djangorestframework/tests/authentication.py
djangorestframework/tests/content.py
djangorestframework/tests/reverse.py
djangorestframework/tests/serializer.py
djangorestframework/views.py
docs/examples.rst
docs/examples/blogpost.rst
docs/examples/modelviews.rst
docs/examples/objectstore.rst
docs/examples/permissions.rst
docs/examples/pygments.rst
docs/examples/views.rst
docs/howto/alternativeframeworks.rst
docs/howto/mixin.rst
docs/howto/reverse.rst
docs/howto/usingurllib2.rst
docs/index.rst
docs/topics/release-notes.md
examples/sandbox/views.py
rest_framework/__init__.py
rest_framework/compat.py
rest_framework/utils/breadcrumbs.py
setup.py
Diffstat (limited to 'rest_framework/serializers.py')
| -rw-r--r-- | rest_framework/serializers.py | 513 |
1 files changed, 513 insertions, 0 deletions
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py new file mode 100644 index 00000000..3d134a74 --- /dev/null +++ b/rest_framework/serializers.py @@ -0,0 +1,513 @@ +import copy +import datetime +import types +from decimal import Decimal +from django.db import models +from django.forms import widgets +from django.utils.datastructures import SortedDict +from rest_framework.compat import get_concrete_model +from rest_framework.fields import * + + +class DictWithMetadata(dict): + """ + A dict-like object, that can have additional properties attached. + """ + pass + + +class SortedDictWithMetadata(SortedDict, DictWithMetadata): + """ + A sorted dict-like object, that can have additional properties attached. + """ + pass + + +def _is_protected_type(obj): + """ + True if the object is a native datatype that does not need to + be serialized further. + """ + return isinstance(obj, ( + types.NoneType, + int, long, + datetime.datetime, datetime.date, datetime.time, + float, Decimal, + basestring) + ) + + +def _get_declared_fields(bases, attrs): + """ + Create a list of serializer field instances from the passed in 'attrs', + plus any fields on the base classes (in 'bases'). + + Note that all fields from the base classes are used. + """ + fields = [(field_name, attrs.pop(field_name)) + for field_name, obj in attrs.items() + if isinstance(obj, Field)] + fields.sort(key=lambda x: x[1].creation_counter) + + # If this class is subclassing another Serializer, add that Serializer's + # fields. Note that we loop over the bases in *reverse*. This is necessary + # in order to the correct order of fields. + for base in bases[::-1]: + if hasattr(base, 'base_fields'): + fields = base.base_fields.items() + fields + + return SortedDict(fields) + + +class SerializerMetaclass(type): + def __new__(cls, name, bases, attrs): + attrs['base_fields'] = _get_declared_fields(bases, attrs) + return super(SerializerMetaclass, cls).__new__(cls, name, bases, attrs) + + +class SerializerOptions(object): + """ + Meta class options for Serializer + """ + def __init__(self, meta): + self.depth = getattr(meta, 'depth', 0) + self.fields = getattr(meta, 'fields', ()) + self.exclude = getattr(meta, 'exclude', ()) + + +class BaseSerializer(Field): + class Meta(object): + pass + + _options_class = SerializerOptions + _dict_class = SortedDictWithMetadata # Set to unsorted dict for backwards compatability with unsorted implementations. + + def __init__(self, data=None, instance=None, context=None, **kwargs): + super(BaseSerializer, self).__init__(**kwargs) + self.fields = copy.deepcopy(self.base_fields) + self.opts = self._options_class(self.Meta) + self.parent = None + self.root = None + + self.context = context or {} + + self.init_data = data + self.object = instance + + self._data = None + self._errors = None + + ##### + # Methods to determine which fields to use when (de)serializing objects. + + def default_fields(self, serialize, obj=None, data=None, nested=False): + """ + Return the complete set of default fields for the object, as a dict. + """ + return {} + + def get_fields(self, serialize, obj=None, data=None, nested=False): + """ + Returns the complete set of fields for the object as a dict. + + This will be the set of any explicitly declared fields, + plus the set of fields returned by default_fields(). + """ + ret = SortedDict() + + # Get the explicitly declared fields + for key, field in self.fields.items(): + ret[key] = field + # Set up the field + field.initialize(parent=self) + + # Add in the default fields + fields = self.default_fields(serialize, obj, data, nested) + for key, val in fields.items(): + if key not in ret: + ret[key] = val + + # If 'fields' is specified, use those fields, in that order. + if self.opts.fields: + new = SortedDict() + for key in self.opts.fields: + new[key] = ret[key] + ret = new + + # Remove anything in 'exclude' + if self.opts.exclude: + for key in self.opts.exclude: + ret.pop(key, None) + + return ret + + ##### + # Field methods - used when the serializer class is itself used as a field. + + def initialize(self, parent): + """ + Same behaviour as usual Field, except that we need to keep track + of state so that we can deal with handling maximum depth. + """ + super(BaseSerializer, self).initialize(parent) + if parent.opts.depth: + self.opts.depth = parent.opts.depth - 1 + + ##### + # Methods to convert or revert from objects <--> primative representations. + + def get_field_key(self, field_name): + """ + Return the key that should be used for a given field. + """ + return field_name + + def convert_object(self, obj): + """ + Core of serialization. + Convert an object into a dictionary of serialized field values. + """ + ret = self._dict_class() + ret.fields = {} + + fields = self.get_fields(serialize=True, obj=obj, nested=bool(self.opts.depth)) + for field_name, field in fields.items(): + key = self.get_field_key(field_name) + value = field.field_to_native(obj, field_name) + ret[key] = value + ret.fields[key] = field + return ret + + def restore_fields(self, data): + """ + Core of deserialization, together with `restore_object`. + Converts a dictionary of data into a dictionary of deserialized fields. + """ + fields = self.get_fields(serialize=False, data=data, nested=bool(self.opts.depth)) + reverted_data = {} + for field_name, field in fields.items(): + try: + field.field_from_native(data, field_name, reverted_data) + except ValidationError as err: + self._errors[field_name] = list(err.messages) + + return reverted_data + + def perform_validation(self, attrs): + """ + Run `validate_<fieldname>()` and `validate()` methods on the serializer + """ + # TODO: refactor this so we're not determining the fields again + fields = self.get_fields(serialize=False, data=attrs, nested=bool(self.opts.depth)) + + for field_name, field in fields.items(): + try: + validate_method = getattr(self, 'validate_%s' % field_name, None) + if validate_method: + source = field.source or field_name + attrs = validate_method(attrs, source) + except ValidationError as err: + self._errors[field_name] = self._errors.get(field_name, []) + list(err.messages) + + try: + attrs = self.validate(attrs) + except ValidationError as err: + self._errors['non_field_errors'] = err.messages + + return attrs + + def validate(self, attrs): + """ + Stub method, to be overridden in Serializer subclasses + """ + return attrs + + def restore_object(self, attrs, instance=None): + """ + Deserialize a dictionary of attributes into an object instance. + You should override this method to control how deserialized objects + are instantiated. + """ + if instance is not None: + instance.update(attrs) + return instance + return attrs + + def to_native(self, obj): + """ + Serialize objects -> primatives. + """ + if isinstance(obj, dict): + return dict([(key, self.to_native(val)) + for (key, val) in obj.items()]) + elif hasattr(obj, '__iter__'): + return [self.to_native(item) for item in obj] + return self.convert_object(obj) + + def from_native(self, data): + """ + Deserialize primatives -> objects. + """ + if hasattr(data, '__iter__') and not isinstance(data, dict): + # TODO: error data when deserializing lists + return (self.from_native(item) for item in data) + + self._errors = {} + if data is not None: + attrs = self.restore_fields(data) + attrs = self.perform_validation(attrs) + else: + self._errors['non_field_errors'] = ['No input provided'] + + if not self._errors: + return self.restore_object(attrs, instance=getattr(self, 'object', None)) + + def field_to_native(self, obj, field_name): + """ + Override default so that we can apply ModelSerializer as a nested + field to relationships. + """ + obj = getattr(obj, self.source or field_name) + + # If the object has an "all" method, assume it's a relationship + if is_simple_callable(getattr(obj, 'all', None)): + return [self.to_native(item) for item in obj.all()] + + return self.to_native(obj) + + @property + def errors(self): + """ + Run deserialization and return error data, + setting self.object if no errors occurred. + """ + if self._errors is None: + obj = self.from_native(self.init_data) + if not self._errors: + self.object = obj + return self._errors + + def is_valid(self): + return not self.errors + + @property + def data(self): + if self._data is None: + self._data = self.to_native(self.object) + return self._data + + def save(self): + """ + Save the deserialized object and return it. + """ + self.object.save() + return self.object + + +class Serializer(BaseSerializer): + __metaclass__ = SerializerMetaclass + + +class ModelSerializerOptions(SerializerOptions): + """ + Meta class options for ModelSerializer + """ + def __init__(self, meta): + super(ModelSerializerOptions, self).__init__(meta) + self.model = getattr(meta, 'model', None) + + +class ModelSerializer(Serializer): + """ + A serializer that deals with model instances and querysets. + """ + _options_class = ModelSerializerOptions + + def default_fields(self, serialize, obj=None, data=None, nested=False): + """ + Return all the fields that should be serialized for the model. + """ + # TODO: Modfiy this so that it's called on init, and drop + # serialize/obj/data arguments. + # + # We *could* provide a hook for dynamic fields, but + # it'd be nice if the default was to generate fields statically + # at the point of __init__ + + cls = self.opts.model + opts = get_concrete_model(cls)._meta + pk_field = opts.pk + while pk_field.rel: + pk_field = pk_field.rel.to._meta.pk + fields = [pk_field] + fields += [field for field in opts.fields if field.serialize] + fields += [field for field in opts.many_to_many if field.serialize] + + ret = SortedDict() + is_pk = True # First field in the list is the pk + + for model_field in fields: + if is_pk: + field = self.get_pk_field(model_field) + is_pk = False + elif model_field.rel and nested: + field = self.get_nested_field(model_field) + elif model_field.rel: + to_many = isinstance(model_field, + models.fields.related.ManyToManyField) + field = self.get_related_field(model_field, to_many=to_many) + else: + field = self.get_field(model_field) + + if field: + field.initialize(parent=self) + ret[model_field.name] = field + + return ret + + def get_pk_field(self, model_field): + """ + Returns a default instance of the pk field. + """ + return Field() + + def get_nested_field(self, model_field): + """ + Creates a default instance of a nested relational field. + """ + return ModelSerializer() + + def get_related_field(self, model_field, to_many=False): + """ + Creates a default instance of a flat relational field. + """ + # TODO: filter queryset using: + # .using(db).complex_filter(self.rel.limit_choices_to) + queryset = model_field.rel.to._default_manager + if to_many: + return ManyPrimaryKeyRelatedField(queryset=queryset) + return PrimaryKeyRelatedField(queryset=queryset) + + def get_field(self, model_field): + """ + Creates a default instance of a basic non-relational field. + """ + kwargs = {} + + kwargs['blank'] = model_field.blank + + if model_field.null: + kwargs['required'] = False + + if model_field.has_default(): + kwargs['required'] = False + kwargs['default'] = model_field.get_default() + + if model_field.__class__ == models.TextField: + kwargs['widget'] = widgets.Textarea + + # TODO: TypedChoiceField? + if model_field.flatchoices: # This ModelField contains choices + kwargs['choices'] = model_field.flatchoices + return ChoiceField(**kwargs) + + field_mapping = { + models.FloatField: FloatField, + models.IntegerField: IntegerField, + models.PositiveIntegerField: IntegerField, + models.SmallIntegerField: IntegerField, + models.PositiveSmallIntegerField: IntegerField, + models.DateTimeField: DateTimeField, + models.DateField: DateField, + models.EmailField: EmailField, + models.CharField: CharField, + models.TextField: CharField, + models.CommaSeparatedIntegerField: CharField, + models.BooleanField: BooleanField, + } + try: + return field_mapping[model_field.__class__](**kwargs) + except KeyError: + return ModelField(model_field=model_field, **kwargs) + + def restore_object(self, attrs, instance=None): + """ + Restore the model instance. + """ + self.m2m_data = {} + + if instance: + for key, val in attrs.items(): + setattr(instance, key, val) + return instance + + for field in self.opts.model._meta.many_to_many: + if field.name in attrs: + self.m2m_data[field.name] = attrs.pop(field.name) + return self.opts.model(**attrs) + + def save(self, save_m2m=True): + """ + Save the deserialized object and return it. + """ + self.object.save() + + if self.m2m_data and save_m2m: + for accessor_name, object_list in self.m2m_data.items(): + setattr(self.object, accessor_name, object_list) + self.m2m_data = {} + + return self.object + + +class HyperlinkedModelSerializerOptions(ModelSerializerOptions): + """ + Options for HyperlinkedModelSerializer + """ + def __init__(self, meta): + super(HyperlinkedModelSerializerOptions, self).__init__(meta) + self.view_name = getattr(meta, 'view_name', None) + + +class HyperlinkedModelSerializer(ModelSerializer): + """ + """ + _options_class = HyperlinkedModelSerializerOptions + _default_view_name = '%(model_name)s-detail' + + url = HyperlinkedIdentityField() + + def __init__(self, *args, **kwargs): + super(HyperlinkedModelSerializer, self).__init__(*args, **kwargs) + if self.opts.view_name is None: + self.opts.view_name = self._get_default_view_name(self.opts.model) + + def _get_default_view_name(self, model): + """ + Return the view name to use if 'view_name' is not specified in 'Meta' + """ + model_meta = model._meta + format_kwargs = { + 'app_label': model_meta.app_label, + 'model_name': model_meta.object_name.lower() + } + return self._default_view_name % format_kwargs + + def get_pk_field(self, model_field): + return None + + def get_related_field(self, model_field, to_many): + """ + Creates a default instance of a flat relational field. + """ + # TODO: filter queryset using: + # .using(db).complex_filter(self.rel.limit_choices_to) + rel = model_field.rel.to + queryset = rel._default_manager + kwargs = { + 'queryset': queryset, + 'view_name': self._get_default_view_name(rel) + } + if to_many: + return ManyHyperlinkedRelatedField(**kwargs) + return HyperlinkedRelatedField(**kwargs) |
