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"""
Interfaces for serializing Django objects.
Usage::
>>> from django.core import serializers
>>> json = serializers.serialize("json", some_query_set)
>>> objects = list(serializers.deserialize("json", json))
To add your own serializers, use the SERIALIZATION_MODULES setting::
SERIALIZATION_MODULES = {
"csv" : "path.to.csv.serializer",
"txt" : "path.to.txt.serializer",
}
"""
from django.conf import settings
# Built-in serializers
BUILTIN_SERIALIZERS = {
"xml" : "django.core.serializers.xml_serializer",
"python" : "django.core.serializers.python",
"json" : "django.core.serializers.json",
}
_serializers = {}
def register_serializer(format, serializer_module):
"""Register a new serializer by passing in a module name."""
module = __import__(serializer_module, '', '', [''])
_serializers[format] = module
def unregister_serializer(format):
"""Unregister a given serializer"""
del _serializers[format]
def get_serializer(format):
if not _serializers:
_load_serializers()
return _serializers[format].Serializer
def get_deserializer(format):
if not _serializers:
_load_serializers()
return _serializers[format].Deserializer
def serialize(format, queryset, **options):
"""
Serialize a queryset (or any iterator that returns database objects) using
a certain serializer.
"""
s = get_serializer(format)()
s.serialize(queryset, **options)
return s.getvalue()
def deserialize(format, stream_or_string):
"""
Deserialize a stream or a string. Returns an iterator that yields ``(obj,
m2m_relation_dict)``, where ``obj`` is a instantiated -- but *unsaved* --
object, and ``m2m_relation_dict`` is a dictionary of ``{m2m_field_name :
list_of_related_objects}``.
"""
d = get_deserializer(format)
return d(stream_or_string)
def _load_serializers():
"""
Register built-in and settings-defined serializers. This is done lazily so
that user code has a chance to (e.g.) set up custom settings without
needing to be careful of import order.
"""
for format in BUILTIN_SERIALIZERS:
register_serializer(format, BUILTIN_SERIALIZERS[format])
if hasattr(settings, "SERIALIZATION_MODULES"):
for format in settings.SERIALIZATION_MODULES:
register_serializer(format, settings.SERIALIZATION_MODULES[format])
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