Created
May 22, 2012 10:53
-
-
Save nagyv/2768310 to your computer and use it in GitHub Desktop.
Google Protobuffer field for Django
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
''' A model field to store and retrieve Google Protocol Buffer objects easily. | |
Uses the BlobField available on GAE for storage. | |
Usage: | |
myfield = ProtobufField(protoclass=MyProtocolClass) | |
where MyProtocolClass is a protocol descriptor class generated from a .proto file. | |
The field is supposed to store only the given kind of protocol messages. | |
The `protoclass` attribute is required. | |
''' | |
from django.db import models | |
from djangotoolbox.fields import BlobField | |
class ProtobufField(BlobField): | |
description = "Storage for protobuffer objects" | |
__metaclass__ = models.SubfieldBase | |
def __init__(self, protoclass, *args, **kwargs): | |
self.protoclass = protoclass | |
super(ProtobufField, self).__init__(*args, **kwargs) | |
def to_python(self, value): | |
if isinstance(value, self.protoclass): | |
return value | |
protobuf = self.protoclass() | |
protobuf.ParseFromString(value) | |
return protobuf | |
def get_prep_value(self, value): | |
return value.SerializeToString() | |
def get_db_prep_value(self, value, connection, prepared=False): | |
if hasattr(value, "SerializeToString"): | |
value = value.SerializeToString() | |
return super(ProtobufField, self).get_db_prep_value(value=value, connection=connection, prepared=prepared) | |
def value_to_string(self, obj): | |
obj = obj.SerializeToString() | |
return super(ProtobufField, self).value_to_string(obj) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment