mirror of
https://github.com/encode/django-rest-framework.git
synced 2024-09-21 11:29:01 +03:00
570 lines
18 KiB
Python
570 lines
18 KiB
Python
import copy
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import datetime
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import types
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from decimal import Decimal
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from django.db import models
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from django.forms import widgets
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from django.utils.datastructures import SortedDict
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from rest_framework.compat import get_concrete_model
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# Note: We do the following so that users of the framework can use this style:
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#
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# example_field = serializers.CharField(...)
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#
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# This helps keep the seperation between model fields, form fields, and
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# serializer fields more explicit.
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from rest_framework.fields import *
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class DictWithMetadata(dict):
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"""
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A dict-like object, that can have additional properties attached.
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"""
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pass
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class SortedDictWithMetadata(SortedDict, DictWithMetadata):
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"""
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A sorted dict-like object, that can have additional properties attached.
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"""
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pass
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def _is_protected_type(obj):
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"""
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True if the object is a native datatype that does not need to
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be serialized further.
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"""
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return isinstance(obj, (
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types.NoneType,
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int, long,
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datetime.datetime, datetime.date, datetime.time,
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float, Decimal,
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basestring)
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)
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def _get_declared_fields(bases, attrs):
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"""
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Create a list of serializer field instances from the passed in 'attrs',
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plus any fields on the base classes (in 'bases').
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Note that all fields from the base classes are used.
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"""
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fields = [(field_name, attrs.pop(field_name))
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for field_name, obj in attrs.items()
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if isinstance(obj, Field)]
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fields.sort(key=lambda x: x[1].creation_counter)
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# If this class is subclassing another Serializer, add that Serializer's
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# fields. Note that we loop over the bases in *reverse*. This is necessary
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# in order to the correct order of fields.
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for base in bases[::-1]:
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if hasattr(base, 'base_fields'):
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fields = base.base_fields.items() + fields
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return SortedDict(fields)
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class SerializerMetaclass(type):
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def __new__(cls, name, bases, attrs):
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attrs['base_fields'] = _get_declared_fields(bases, attrs)
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return super(SerializerMetaclass, cls).__new__(cls, name, bases, attrs)
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class SerializerOptions(object):
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"""
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Meta class options for Serializer
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"""
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def __init__(self, meta):
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self.depth = getattr(meta, 'depth', 0)
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self.fields = getattr(meta, 'fields', ())
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self.exclude = getattr(meta, 'exclude', ())
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class BaseSerializer(Field):
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class Meta(object):
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pass
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_options_class = SerializerOptions
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_dict_class = SortedDictWithMetadata # Set to unsorted dict for backwards compatibility with unsorted implementations.
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def __init__(self, instance=None, data=None, files=None, context=None, partial=False, **kwargs):
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super(BaseSerializer, self).__init__(**kwargs)
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self.opts = self._options_class(self.Meta)
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self.fields = copy.deepcopy(self.base_fields)
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self.parent = None
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self.root = None
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self.partial = partial
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self.context = context or {}
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self.init_data = data
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self.init_files = files
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self.object = instance
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self.default_fields = self.get_default_fields()
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self._data = None
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self._files = None
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self._errors = None
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#####
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# Methods to determine which fields to use when (de)serializing objects.
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def get_default_fields(self):
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"""
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Return the complete set of default fields for the object, as a dict.
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"""
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return {}
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def get_excluded_fieldnames(self):
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"""
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Returns the fieldnames that should not be validated.
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"""
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excluded_fields = list(self.opts.exclude)
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for field in self.fields.keys() + self.default_fields.keys():
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if self.opts.fields:
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if field not in self.opts.fields + self.opts.exclude:
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excluded_fields.append(field)
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return excluded_fields
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def get_fields(self):
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"""
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Returns the complete set of fields for the object as a dict.
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This will be the set of any explicitly declared fields,
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plus the set of fields returned by get_default_fields().
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"""
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ret = SortedDict()
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# Get the explicitly declared fields
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for key, field in self.fields.items():
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ret[key] = field
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# Set up the field
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field.initialize(parent=self, field_name=key)
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# Add in the default fields
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for key, val in self.default_fields.items():
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if key not in ret:
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ret[key] = val
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# If 'fields' is specified, use those fields, in that order.
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if self.opts.fields:
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new = SortedDict()
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for key in self.opts.fields:
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new[key] = ret[key]
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ret = new
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# Remove anything in 'exclude'
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if self.opts.exclude:
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for key in self.opts.exclude:
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ret.pop(key, None)
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return ret
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#####
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# Field methods - used when the serializer class is itself used as a field.
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def initialize(self, parent, field_name):
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"""
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Same behaviour as usual Field, except that we need to keep track
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of state so that we can deal with handling maximum depth.
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"""
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super(BaseSerializer, self).initialize(parent, field_name)
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if parent.opts.depth:
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self.opts.depth = parent.opts.depth - 1
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#####
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# Methods to convert or revert from objects <--> primitive representations.
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def get_field_key(self, field_name):
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"""
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Return the key that should be used for a given field.
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"""
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return field_name
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def convert_object(self, obj):
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"""
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Core of serialization.
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Convert an object into a dictionary of serialized field values.
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"""
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ret = self._dict_class()
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ret.fields = {}
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fields = self.get_fields()
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for field_name, field in fields.items():
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key = self.get_field_key(field_name)
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value = field.field_to_native(obj, field_name)
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ret[key] = value
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ret.fields[key] = field
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return ret
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def restore_fields(self, data, files):
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"""
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Core of deserialization, together with `restore_object`.
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Converts a dictionary of data into a dictionary of deserialized fields.
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"""
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fields = self.get_fields()
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reverted_data = {}
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for field_name, field in fields.items():
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try:
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field.field_from_native(data, files, field_name, reverted_data)
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except ValidationError as err:
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self._errors[field_name] = list(err.messages)
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return reverted_data
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def perform_validation(self, attrs):
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"""
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Run `validate_<fieldname>()` and `validate()` methods on the serializer
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"""
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# TODO: refactor this so we're not determining the fields again
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fields = self.get_fields()
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for field_name, field in fields.items():
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try:
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validate_method = getattr(self, 'validate_%s' % field_name, None)
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if validate_method:
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source = field.source or field_name
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attrs = validate_method(attrs, source)
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except ValidationError as err:
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self._errors[field_name] = self._errors.get(field_name, []) + list(err.messages)
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# We don't run .validate() because field-validation failed and thus `attrs` may not be complete.
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# which in turn can cause inconsistent validation errors.
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if not self._errors:
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try:
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attrs = self.validate(attrs)
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except ValidationError as err:
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if hasattr(err, 'message_dict'):
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for field_name, error_messages in err.message_dict.items():
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self._errors[field_name] = self._errors.get(field_name, []) + list(error_messages)
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elif hasattr(err, 'messages'):
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self._errors['non_field_errors'] = err.messages
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return attrs
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def validate(self, attrs):
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"""
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Stub method, to be overridden in Serializer subclasses
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"""
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return attrs
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def restore_object(self, attrs, instance=None):
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"""
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Deserialize a dictionary of attributes into an object instance.
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You should override this method to control how deserialized objects
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are instantiated.
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"""
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if instance is not None:
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instance.update(attrs)
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return instance
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return attrs
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def to_native(self, obj):
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"""
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Serialize objects -> primitives.
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"""
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if hasattr(obj, '__iter__'):
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return [self.convert_object(item) for item in obj]
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return self.convert_object(obj)
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def from_native(self, data, files):
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"""
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Deserialize primitives -> objects.
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"""
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if hasattr(data, '__iter__') and not isinstance(data, dict):
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# TODO: error data when deserializing lists
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return (self.from_native(item) for item in data)
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self._errors = {}
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if data is not None or files is not None:
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attrs = self.restore_fields(data, files)
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attrs = self.perform_validation(attrs)
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else:
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self._errors['non_field_errors'] = ['No input provided']
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if not self._errors:
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return self.restore_object(attrs, instance=getattr(self, 'object', None))
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def field_to_native(self, obj, field_name):
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"""
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Override default so that we can apply ModelSerializer as a nested
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field to relationships.
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"""
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obj = getattr(obj, self.source or field_name)
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if is_simple_callable(obj):
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obj = obj()
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# If the object has an "all" method, assume it's a relationship
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if is_simple_callable(getattr(obj, 'all', None)):
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return [self.to_native(item) for item in obj.all()]
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return self.to_native(obj)
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@property
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def errors(self):
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"""
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Run deserialization and return error data,
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setting self.object if no errors occurred.
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"""
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if self._errors is None:
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obj = self.from_native(self.init_data, self.init_files)
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if not self._errors:
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self.object = obj
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return self._errors
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def is_valid(self):
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return not self.errors
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@property
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def data(self):
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if self._data is None:
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self._data = self.to_native(self.object)
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return self._data
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def save(self):
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"""
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Save the deserialized object and return it.
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"""
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self.object.save()
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return self.object
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class Serializer(BaseSerializer):
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__metaclass__ = SerializerMetaclass
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class ModelSerializerOptions(SerializerOptions):
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"""
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Meta class options for ModelSerializer
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"""
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def __init__(self, meta):
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super(ModelSerializerOptions, self).__init__(meta)
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self.model = getattr(meta, 'model', None)
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self.read_only_fields = getattr(meta, 'read_only_fields', ())
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class ModelSerializer(Serializer):
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"""
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A serializer that deals with model instances and querysets.
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"""
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_options_class = ModelSerializerOptions
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def get_default_fields(self):
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"""
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Return all the fields that should be serialized for the model.
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"""
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cls = self.opts.model
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opts = get_concrete_model(cls)._meta
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pk_field = opts.pk
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while pk_field.rel:
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pk_field = pk_field.rel.to._meta.pk
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fields = [pk_field]
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fields += [field for field in opts.fields if field.serialize]
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fields += [field for field in opts.many_to_many if field.serialize]
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ret = SortedDict()
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nested = bool(self.opts.depth)
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is_pk = True # First field in the list is the pk
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for model_field in fields:
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if is_pk:
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field = self.get_pk_field(model_field)
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is_pk = False
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elif model_field.rel and nested:
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field = self.get_nested_field(model_field)
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elif model_field.rel:
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to_many = isinstance(model_field,
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models.fields.related.ManyToManyField)
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field = self.get_related_field(model_field, to_many=to_many)
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else:
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field = self.get_field(model_field)
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if field:
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field.initialize(parent=self, field_name=model_field.name)
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ret[model_field.name] = field
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for field_name in self.opts.read_only_fields:
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assert field_name in ret, \
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"read_only_fields on '%s' included invalid item '%s'" % \
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(self.__class__.__name__, field_name)
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ret[field_name].read_only = True
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return ret
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def get_pk_field(self, model_field):
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"""
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Returns a default instance of the pk field.
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"""
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return Field()
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def get_nested_field(self, model_field):
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"""
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Creates a default instance of a nested relational field.
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"""
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class NestedModelSerializer(ModelSerializer):
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class Meta:
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model = model_field.rel.to
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return NestedModelSerializer()
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def get_related_field(self, model_field, to_many=False):
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"""
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Creates a default instance of a flat relational field.
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"""
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# TODO: filter queryset using:
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# .using(db).complex_filter(self.rel.limit_choices_to)
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queryset = model_field.rel.to._default_manager
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if to_many:
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return ManyPrimaryKeyRelatedField(queryset=queryset)
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return PrimaryKeyRelatedField(queryset=queryset)
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def get_field(self, model_field):
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"""
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Creates a default instance of a basic non-relational field.
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"""
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kwargs = {}
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kwargs['blank'] = model_field.blank
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if model_field.null:
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kwargs['required'] = False
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if model_field.has_default():
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kwargs['required'] = False
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kwargs['default'] = model_field.get_default()
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if model_field.__class__ == models.TextField:
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kwargs['widget'] = widgets.Textarea
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# TODO: TypedChoiceField?
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if model_field.flatchoices: # This ModelField contains choices
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kwargs['choices'] = model_field.flatchoices
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return ChoiceField(**kwargs)
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field_mapping = {
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models.FloatField: FloatField,
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models.IntegerField: IntegerField,
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models.PositiveIntegerField: IntegerField,
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models.SmallIntegerField: IntegerField,
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models.PositiveSmallIntegerField: IntegerField,
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models.DateTimeField: DateTimeField,
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models.DateField: DateField,
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models.EmailField: EmailField,
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models.CharField: CharField,
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models.URLField: URLField,
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models.SlugField: SlugField,
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models.TextField: CharField,
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models.CommaSeparatedIntegerField: CharField,
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models.BooleanField: BooleanField,
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models.FileField: FileField,
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models.ImageField: ImageField,
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}
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try:
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return field_mapping[model_field.__class__](**kwargs)
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except KeyError:
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return ModelField(model_field=model_field, **kwargs)
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def validate(self, attrs):
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copied_attrs = copy.deepcopy(attrs)
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restored_object = self.restore_object(copied_attrs, instance=getattr(self, 'object', None))
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self.perform_model_validation(restored_object)
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return attrs
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def perform_model_validation(self, restored_object):
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# Call Django's full_clean() which in turn calls: Model.clean_fields(), Model.clean(), Model.validat_unique()
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restored_object.full_clean(exclude=list(self.get_excluded_fieldnames()))
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def restore_object(self, attrs, instance=None):
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"""
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Restore the model instance.
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"""
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self.m2m_data = {}
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if instance is not None:
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for key, val in attrs.items():
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setattr(instance, key, val)
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return instance
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# Reverse relations
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for (obj, model) in self.opts.model._meta.get_all_related_m2m_objects_with_model():
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field_name = obj.field.related_query_name()
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if field_name in attrs:
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self.m2m_data[field_name] = attrs.pop(field_name)
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# Forward relations
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for field in self.opts.model._meta.many_to_many:
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if field.name in attrs:
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self.m2m_data[field.name] = attrs.pop(field.name)
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return self.opts.model(**attrs)
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def save(self, save_m2m=True):
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"""
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Save the deserialized object and return it.
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"""
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self.object.save()
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if getattr(self, 'm2m_data', None) and save_m2m:
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for accessor_name, object_list in self.m2m_data.items():
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setattr(self.object, accessor_name, object_list)
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self.m2m_data = {}
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return self.object
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class HyperlinkedModelSerializerOptions(ModelSerializerOptions):
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"""
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Options for HyperlinkedModelSerializer
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"""
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def __init__(self, meta):
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super(HyperlinkedModelSerializerOptions, self).__init__(meta)
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self.view_name = getattr(meta, 'view_name', None)
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class HyperlinkedModelSerializer(ModelSerializer):
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"""
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"""
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_options_class = HyperlinkedModelSerializerOptions
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_default_view_name = '%(model_name)s-detail'
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url = HyperlinkedIdentityField()
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def __init__(self, *args, **kwargs):
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super(HyperlinkedModelSerializer, self).__init__(*args, **kwargs)
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if self.opts.view_name is None:
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self.opts.view_name = self._get_default_view_name(self.opts.model)
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def _get_default_view_name(self, model):
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"""
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Return the view name to use if 'view_name' is not specified in 'Meta'
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"""
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model_meta = model._meta
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format_kwargs = {
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'app_label': model_meta.app_label,
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'model_name': model_meta.object_name.lower()
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}
|
|
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)
|