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Python

# Copyright © 2017 Tom Hacohen
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, version 3.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import base64
from django.core.files.base import ContentFile
from django.core import exceptions as django_exceptions
from django.contrib.auth import get_user_model
from django.db import transaction
from rest_framework import serializers
from . import models
from .utils import get_user_queryset, create_user
User = get_user_model()
def process_revisions_for_item(item, revision_data):
chunks_objs = []
chunks = revision_data.pop('chunks_relation')
for chunk in chunks:
uid = chunk[0]
chunk_obj = models.CollectionItemChunk.objects.filter(uid=uid).first()
if len(chunk) > 1:
content = chunk[1]
# If the chunk already exists we assume it's fine. Otherwise, we upload it.
if chunk_obj is None:
chunk_obj = models.CollectionItemChunk(uid=uid, item=item)
chunk_obj.chunkFile.save('IGNORED', ContentFile(content))
chunk_obj.save()
else:
if chunk_obj is None:
raise serializers.ValidationError('Tried to create a new chunk without content')
chunks_objs.append(chunk_obj)
stoken = models.Stoken.objects.create()
revision = models.CollectionItemRevision.objects.create(**revision_data, item=item, stoken=stoken)
for chunk in chunks_objs:
models.RevisionChunkRelation.objects.create(chunk=chunk, revision=revision)
return revision
def b64encode(value):
return base64.urlsafe_b64encode(value).decode('ascii').strip('=')
def b64decode(data):
data += "=" * ((4 - len(data) % 4) % 4)
return base64.urlsafe_b64decode(data)
def b64decode_or_bytes(data):
if isinstance(data, bytes):
return data
else:
return b64decode(data)
class BinaryBase64Field(serializers.Field):
def to_representation(self, value):
return value
def to_internal_value(self, data):
return b64decode_or_bytes(data)
class CollectionEncryptionKeyField(BinaryBase64Field):
def get_attribute(self, instance):
request = self.context.get('request', None)
if request is not None:
return instance.members.get(user=request.user).encryptionKey
return None
class CollectionContentField(BinaryBase64Field):
def get_attribute(self, instance):
request = self.context.get('request', None)
if request is not None:
return instance.members.get(user=request.user).encryptionKey
return None
class UserSlugRelatedField(serializers.SlugRelatedField):
def get_queryset(self):
view = self.context.get('view', None)
return get_user_queryset(super().get_queryset(), view)
def __init__(self, **kwargs):
super().__init__(slug_field=User.USERNAME_FIELD, **kwargs)
def to_internal_value(self, data):
return super().to_internal_value(data.lower())
class ChunksField(serializers.RelatedField):
def to_representation(self, obj):
obj = obj.chunk
if self.context.get('prefetch'):
with open(obj.chunkFile.path, 'rb') as f:
return (obj.uid, f.read())
else:
return (obj.uid, )
def to_internal_value(self, data):
if data[0] is None or data[1] is None:
raise serializers.ValidationError('null is not allowed')
return (data[0], b64decode_or_bytes(data[1]))
class CollectionItemChunkSerializer(serializers.ModelSerializer):
class Meta:
model = models.CollectionItemChunk
fields = ('uid', 'chunkFile')
class CollectionItemRevisionSerializer(serializers.ModelSerializer):
chunks = ChunksField(
source='chunks_relation',
queryset=models.RevisionChunkRelation.objects.all(),
many=True
)
meta = BinaryBase64Field()
class Meta:
model = models.CollectionItemRevision
fields = ('chunks', 'meta', 'uid', 'deleted')
class CollectionItemSerializer(serializers.ModelSerializer):
encryptionKey = BinaryBase64Field(required=False, default=None, allow_null=True)
etag = serializers.CharField(allow_null=True, write_only=True)
content = CollectionItemRevisionSerializer(many=False)
class Meta:
model = models.CollectionItem
fields = ('uid', 'version', 'encryptionKey', 'content', 'etag')
def create(self, validated_data):
"""Function that's called when this serializer creates an item"""
validate_etag = self.context.get('validate_etag', False)
etag = validated_data.pop('etag')
revision_data = validated_data.pop('content')
uid = validated_data.pop('uid')
Model = self.__class__.Meta.model
with transaction.atomic():
instance, created = Model.objects.get_or_create(uid=uid, defaults=validated_data)
cur_etag = instance.etag if not created else None
if validate_etag and cur_etag != etag:
raise serializers.ValidationError('Wrong etag. Expected {} got {}'.format(cur_etag, etag))
if not created:
# We don't have to use select_for_update here because the unique constraint on current guards against
# the race condition. But it's a good idea because it'll lock and wait rather than fail.
current_revision = instance.revisions.filter(current=True).select_for_update().first()
current_revision.current = None
current_revision.save()
process_revisions_for_item(instance, revision_data)
return instance
def update(self, instance, validated_data):
# We never update, we always update in the create method
raise NotImplementedError()
class CollectionItemDepSerializer(serializers.ModelSerializer):
etag = serializers.CharField()
class Meta:
model = models.CollectionItem
fields = ('uid', 'etag')
def validate(self, data):
item = self.__class__.Meta.model.objects.get(uid=data['uid'])
etag = data['etag']
if item.etag != etag:
raise serializers.ValidationError('Wrong etag. Expected {} got {}'.format(item.etag, etag))
return data
class CollectionItemBulkGetSerializer(serializers.ModelSerializer):
etag = serializers.CharField(required=False)
class Meta:
model = models.CollectionItem
fields = ('uid', 'etag')
class CollectionSerializer(serializers.ModelSerializer):
collectionKey = CollectionEncryptionKeyField()
accessLevel = serializers.SerializerMethodField('get_access_level_from_context')
stoken = serializers.CharField(read_only=True)
uid = serializers.CharField(source='main_item.uid')
encryptionKey = BinaryBase64Field(source='main_item.encryptionKey', required=False, default=None, allow_null=True)
etag = serializers.CharField(allow_null=True, write_only=True)
version = serializers.IntegerField(min_value=0, source='main_item.version')
content = CollectionItemRevisionSerializer(many=False, source='main_item.content')
class Meta:
model = models.Collection
fields = ('uid', 'version', 'accessLevel', 'encryptionKey', 'collectionKey', 'content', 'stoken', 'etag')
def get_access_level_from_context(self, obj):
request = self.context.get('request', None)
if request is not None:
return obj.members.get(user=request.user).accessLevel
return None
def create(self, validated_data):
"""Function that's called when this serializer creates an item"""
collection_key = validated_data.pop('collectionKey')
etag = validated_data.pop('etag')
main_item_data = validated_data.pop('main_item')
uid = main_item_data.pop('uid')
version = main_item_data.pop('version')
revision_data = main_item_data.pop('content')
encryption_key = main_item_data.pop('encryptionKey')
instance = self.__class__.Meta.model(**validated_data)
with transaction.atomic():
if etag is not None:
raise serializers.ValidationError('etag is not None')
instance.save()
main_item = models.CollectionItem.objects.create(
uid=uid, encryptionKey=encryption_key, version=version, collection=instance)
instance.main_item = main_item
instance.save()
process_revisions_for_item(main_item, revision_data)
models.CollectionMember(collection=instance,
stoken=models.Stoken.objects.create(),
user=validated_data.get('owner'),
accessLevel=models.AccessLevels.ADMIN,
encryptionKey=collection_key,
).save()
return instance
def update(self, instance, validated_data):
raise NotImplementedError()
class CollectionMemberSerializer(serializers.ModelSerializer):
username = UserSlugRelatedField(
source='user',
read_only=True,
)
class Meta:
model = models.CollectionMember
fields = ('username', 'accessLevel')
def create(self, validated_data):
raise NotImplementedError()
def update(self, instance, validated_data):
with transaction.atomic():
# We only allow updating accessLevel
access_level = validated_data.pop('accessLevel')
if instance.accessLevel != access_level:
instance.stoken = models.Stoken.objects.create()
instance.accessLevel = access_level
instance.save()
return instance
class CollectionInvitationSerializer(serializers.ModelSerializer):
username = UserSlugRelatedField(
source='user',
queryset=User.objects
)
collection = serializers.CharField(source='collection.uid')
fromPubkey = BinaryBase64Field(source='fromMember.user.userinfo.pubkey', read_only=True)
signedEncryptionKey = BinaryBase64Field()
class Meta:
model = models.CollectionInvitation
fields = ('username', 'uid', 'collection', 'signedEncryptionKey', 'accessLevel', 'fromPubkey', 'version')
def validate_user(self, value):
request = self.context['request']
if request.user.username == value.lower():
raise serializers.ValidationError('Inviting yourself is not allowed')
return value
def create(self, validated_data):
request = self.context['request']
collection = validated_data.pop('collection')
member = collection.members.get(user=request.user)
with transaction.atomic():
return type(self).Meta.model.objects.create(**validated_data, fromMember=member)
def update(self, instance, validated_data):
with transaction.atomic():
instance.accessLevel = validated_data.pop('accessLevel')
instance.signedEncryptionKey = validated_data.pop('signedEncryptionKey')
instance.save()
return instance
class InvitationAcceptSerializer(serializers.Serializer):
encryptionKey = BinaryBase64Field()
def create(self, validated_data):
with transaction.atomic():
invitation = self.context['invitation']
encryption_key = validated_data.get('encryptionKey')
member = models.CollectionMember.objects.create(
collection=invitation.collection,
stoken=models.Stoken.objects.create(),
user=invitation.user,
accessLevel=invitation.accessLevel,
encryptionKey=encryption_key,
)
models.CollectionMemberRemoved.objects.filter(
user=invitation.user, collection=invitation.collection).delete()
invitation.delete()
return member
def update(self, instance, validated_data):
raise NotImplementedError()
class UserSerializer(serializers.ModelSerializer):
pubkey = BinaryBase64Field(source='userinfo.pubkey')
encryptedContent = BinaryBase64Field(source='userinfo.encryptedContent')
class Meta:
model = User
fields = (User.USERNAME_FIELD, User.EMAIL_FIELD, 'pubkey', 'encryptedContent')
class UserInfoPubkeySerializer(serializers.ModelSerializer):
pubkey = BinaryBase64Field()
class Meta:
model = models.UserInfo
fields = ('pubkey', )
class UserSignupSerializer(serializers.ModelSerializer):
class Meta:
model = User
fields = (User.USERNAME_FIELD, User.EMAIL_FIELD)
extra_kwargs = {
'username': {'validators': []}, # We specifically validate in SignupSerializer
}
class AuthenticationSignupSerializer(serializers.Serializer):
user = UserSignupSerializer(many=False)
salt = BinaryBase64Field()
loginPubkey = BinaryBase64Field()
pubkey = BinaryBase64Field()
encryptedContent = BinaryBase64Field()
def create(self, validated_data):
"""Function that's called when this serializer creates an item"""
user_data = validated_data.pop('user')
with transaction.atomic():
try:
view = self.context.get('view', None)
user_queryset = get_user_queryset(User.objects.all(), view)
instance = user_queryset.get(**{User.USERNAME_FIELD: user_data['username'].lower()})
except User.DoesNotExist:
# Create the user and save the casing the user chose as the first name
try:
instance = create_user(**user_data, password=None, first_name=user_data['username'], view=view)
except Exception as e:
raise serializers.ValidationError(e)
if hasattr(instance, 'userinfo'):
raise serializers.ValidationError('User already exists')
try:
instance.clean_fields()
except django_exceptions.ValidationError as e:
raise serializers.ValidationError(e)
# FIXME: send email verification
models.UserInfo.objects.create(**validated_data, owner=instance)
return instance
def update(self, instance, validated_data):
raise NotImplementedError()
class AuthenticationLoginChallengeSerializer(serializers.Serializer):
username = serializers.CharField(required=True)
def create(self, validated_data):
raise NotImplementedError()
def update(self, instance, validated_data):
raise NotImplementedError()
class AuthenticationLoginSerializer(serializers.Serializer):
response = BinaryBase64Field()
signature = BinaryBase64Field()
def create(self, validated_data):
raise NotImplementedError()
def update(self, instance, validated_data):
raise NotImplementedError()
class AuthenticationLoginInnerSerializer(AuthenticationLoginChallengeSerializer):
challenge = BinaryBase64Field()
host = serializers.CharField()
action = serializers.CharField()
def create(self, validated_data):
raise NotImplementedError()
def update(self, instance, validated_data):
raise NotImplementedError()
class AuthenticationChangePasswordInnerSerializer(AuthenticationLoginInnerSerializer):
loginPubkey = BinaryBase64Field()
encryptedContent = BinaryBase64Field()
class Meta:
model = models.UserInfo
fields = ('loginPubkey', 'encryptedContent')
def create(self, validated_data):
raise NotImplementedError()
def update(self, instance, validated_data):
with transaction.atomic():
instance.loginPubkey = validated_data.pop('loginPubkey')
instance.encryptedContent = validated_data.pop('encryptedContent')
instance.save()
return instance