# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Contains classes used for the Django ORM storage."""
import base64
import pickle
from django.db import models
from django.utils import encoding
import oauth2client
class CredentialsField(models.Field):
"""Django ORM field for storing OAuth2 Credentials."""
def __init__(self, *args, **kwargs):
if 'null' not in kwargs:
kwargs['null'] = True
super(CredentialsField, self).__init__(*args, **kwargs)
def get_internal_type(self):
return 'BinaryField'
def from_db_value(self, value, expression, connection, context):
"""Overrides ``models.Field`` method. This converts the value
returned from the database to an instance of this class.
"""
return self.to_python(value)
def to_python(self, value):
"""Overrides ``models.Field`` method. This is used to convert
bytes (from serialization etc) to an instance of this class"""
if value is None:
return None
elif isinstance(value, oauth2client.client.Credentials):
return value
else:
return pickle.loads(base64.b64decode(encoding.smart_bytes(value)))
def get_prep_value(self, value):
"""Overrides ``models.Field`` method. This is used to convert
the value from an instances of this class to bytes that can be
inserted into the database.
"""
if value is None:
return None
else:
return encoding.smart_text(base64.b64encode(pickle.dumps(value)))
def value_to_string(self, obj):
"""Convert the field value from the provided model to a string.
Used during model serialization.
Args:
obj: db.Model, model object
Returns:
string, the serialized field value
"""
value = self._get_val_from_obj(obj)
return self.get_prep_value(value)
