+
−"""
+
−Module for abstract serializer/unserializer base classes.
+
−"""
+
−
+
−from StringIO import StringIO
+
−
+
−from django.db import models
+
−from django.utils.encoding import smart_str, smart_unicode
+
−from django.utils import datetime_safe
+
−
+
−class SerializationError(Exception):
+
−    """Something bad happened during serialization."""
+
−    pass
+
−
+
−class DeserializationError(Exception):
+
−    """Something bad happened during deserialization."""
+
−    pass
+
−
+
−class Serializer(object):
+
−    """
+
−    Abstract serializer base class.
+
−    """
+
−
+
−    # Indicates if the implemented serializer is only available for
+
−    # internal Django use.
+
−    internal_use_only = False
+
−
+
−    def serialize(self, queryset, **options):
+
−        """
+
−        Serialize a queryset.
+
−        """
+
−        self.options = options
+
−
+
−        self.stream = options.get("stream", StringIO())
+
−        self.selected_fields = options.get("fields")
+
−
+
−        self.start_serialization()
+
−        for obj in queryset:
+
−            self.start_object(obj)
+
−            for field in obj._meta.local_fields:
+
−                if field.serialize:
+
−                    if field.rel is None:
+
−                        if self.selected_fields is None or field.attname in self.selected_fields:
+
−                            self.handle_field(obj, field)
+
−                    else:
+
−                        if self.selected_fields is None or field.attname[:-3] in self.selected_fields:
+
−                            self.handle_fk_field(obj, field)
+
−            for field in obj._meta.many_to_many:
+
−                if field.serialize:
+
−                    if self.selected_fields is None or field.attname in self.selected_fields:
+
−                        self.handle_m2m_field(obj, field)
+
−            self.end_object(obj)
+
−        self.end_serialization()
+
−        return self.getvalue()
+
−
+
−    def get_string_value(self, obj, field):
+
−        """
+
−        Convert a field's value to a string.
+
−        """
+
−        return smart_unicode(field.value_to_string(obj))
+
−
+
−    def start_serialization(self):
+
−        """
+
−        Called when serializing of the queryset starts.
+
−        """
+
−        raise NotImplementedError
+
−
+
−    def end_serialization(self):
+
−        """
+
−        Called when serializing of the queryset ends.
+
−        """
+
−        pass
+
−
+
−    def start_object(self, obj):
+
−        """
+
−        Called when serializing of an object starts.
+
−        """
+
−        raise NotImplementedError
+
−
+
−    def end_object(self, obj):
+
−        """
+
−        Called when serializing of an object ends.
+
−        """
+
−        pass
+
−
+
−    def handle_field(self, obj, field):
+
−        """
+
−        Called to handle each individual (non-relational) field on an object.
+
−        """
+
−        raise NotImplementedError
+
−
+
−    def handle_fk_field(self, obj, field):
+
−        """
+
−        Called to handle a ForeignKey field.
+
−        """
+
−        raise NotImplementedError
+
−
+
−    def handle_m2m_field(self, obj, field):
+
−        """
+
−        Called to handle a ManyToManyField.
+
−        """
+
−        raise NotImplementedError
+
−
+
−    def getvalue(self):
+
−        """
+
−        Return the fully serialized queryset (or None if the output stream is
+
−        not seekable).
+
−        """
+
−        if callable(getattr(self.stream, 'getvalue', None)):
+
−            return self.stream.getvalue()
+
−
+
−class Deserializer(object):
+
−    """
+
−    Abstract base deserializer class.
+
−    """
+
−
+
−    def __init__(self, stream_or_string, **options):
+
−        """
+
−        Init this serializer given a stream or a string
+
−        """
+
−        self.options = options
+
−        if isinstance(stream_or_string, basestring):
+
−            self.stream = StringIO(stream_or_string)
+
−        else:
+
−            self.stream = stream_or_string
+
−        # hack to make sure that the models have all been loaded before
+
−        # deserialization starts (otherwise subclass calls to get_model()
+
−        # and friends might fail...)
+
−        models.get_apps()
+
−
+
−    def __iter__(self):
+
−        return self
+
−
+
−    def next(self):
+
−        """Iteration iterface -- return the next item in the stream"""
+
−        raise NotImplementedError
+
−
+
−class DeserializedObject(object):
+
−    """
+
−    A deserialized model.
+
−
+
−    Basically a container for holding the pre-saved deserialized data along
+
−    with the many-to-many data saved with the object.
+
−
+
−    Call ``save()`` to save the object (with the many-to-many data) to the
+
−    database; call ``save(save_m2m=False)`` to save just the object fields
+
−    (and not touch the many-to-many stuff.)
+
−    """
+
−
+
−    def __init__(self, obj, m2m_data=None):
+
−        self.object = obj
+
−        self.m2m_data = m2m_data
+
−
+
−    def __repr__(self):
+
−        return "<DeserializedObject: %s>" % smart_str(self.object)
+
−
+
−    def save(self, save_m2m=True):
+
−        # Call save on the Model baseclass directly. This bypasses any
+
−        # model-defined save. The save is also forced to be raw.
+
−        # This ensures that the data that is deserialized is literally
+
−        # what came from the file, not post-processed by pre_save/save
+
−        # methods.
+
−        models.Model.save_base(self.object, raw=True)
+
−        if self.m2m_data and save_m2m:
+
−            for accessor_name, object_list in self.m2m_data.items():
+
−                setattr(self.object, accessor_name, object_list)
+
−
+
−        # prevent a second (possibly accidental) call to save() from saving
+
−        # the m2m data twice.
+
−        self.m2m_data = None