201 lines
7.0 KiB
Python
201 lines
7.0 KiB
Python
# Copyright © 2017 Tom Hacohen
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, version 3.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import base64
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from django.core.files.base import ContentFile
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from django.contrib.auth import get_user_model
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from django.db import transaction
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from rest_framework import serializers
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from . import models
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User = get_user_model()
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def process_revisions_for_item(item, revision_data):
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chunks_objs = []
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chunks = revision_data.pop('chunks_relation')
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for chunk in chunks:
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uid = chunk[0]
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if len(chunk) > 1:
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content = chunk[1]
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chunk = models.CollectionItemChunk(uid=uid, item=item)
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chunk.chunkFile.save('IGNORED', ContentFile(content))
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chunk.save()
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chunks_objs.append(chunk)
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else:
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chunk = models.CollectionItemChunk.objects.get(uid=uid)
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chunks_objs.append(chunk)
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revision = models.CollectionItemRevision.objects.create(**revision_data, item=item)
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for chunk in chunks_objs:
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models.RevisionChunkRelation.objects.create(chunk=chunk, revision=revision)
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return revision
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def b64encode(value):
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return base64.urlsafe_b64encode(value).decode('ascii').strip('=')
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def b64decode(data):
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data += "=" * ((4 - len(data) % 4) % 4)
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return base64.urlsafe_b64decode(data)
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class BinaryBase64Field(serializers.Field):
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def to_representation(self, value):
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return b64encode(value)
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def to_internal_value(self, data):
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return b64decode(data)
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class CollectionEncryptionKeyField(BinaryBase64Field):
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def get_attribute(self, instance):
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request = self.context.get('request', None)
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if request is not None:
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return instance.members.get(user=request.user).encryptionKey
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return None
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class CollectionContentField(BinaryBase64Field):
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def get_attribute(self, instance):
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request = self.context.get('request', None)
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if request is not None:
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return instance.members.get(user=request.user).encryptionKey
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return None
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class ChunksField(serializers.RelatedField):
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def to_representation(self, obj):
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obj = obj.chunk
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inline = self.context.get('inline', False)
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if inline:
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with open(obj.chunkFile.path, 'rb') as f:
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return (obj.uid, b64encode(f.read()))
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else:
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return (obj.uid, )
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def to_internal_value(self, data):
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return (data[0], b64decode(data[1]))
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class CollectionItemChunkSerializer(serializers.ModelSerializer):
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class Meta:
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model = models.CollectionItemChunk
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fields = ('uid', 'chunkFile')
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class CollectionItemRevisionSerializer(serializers.ModelSerializer):
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chunks = ChunksField(
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source='chunks_relation',
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queryset=models.RevisionChunkRelation.objects.all(),
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many=True
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)
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meta = BinaryBase64Field()
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class Meta:
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model = models.CollectionItemRevision
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fields = ('chunks', 'meta', 'uid', 'deleted')
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class CollectionItemSerializer(serializers.ModelSerializer):
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encryptionKey = BinaryBase64Field()
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content = CollectionItemRevisionSerializer(many=False)
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class Meta:
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model = models.CollectionItem
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fields = ('uid', 'version', 'encryptionKey', 'content')
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def create(self, validated_data):
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"""Function that's called when this serializer creates an item"""
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revision_data = validated_data.pop('content')
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instance = self.__class__.Meta.model(**validated_data)
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with transaction.atomic():
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instance.save()
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process_revisions_for_item(instance, revision_data)
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return instance
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def update(self, instance, validated_data):
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"""Function that's called when this serializer is meant to update an item"""
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revision_data = validated_data.pop('content')
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with transaction.atomic():
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# We don't have to use select_for_update here because the unique constraint on current guards against
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# the race condition. But it's a good idea because it'll lock and wait rather than fail.
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current_revision = instance.revisions.filter(current=True).select_for_update().first()
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current_revision.current = None
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current_revision.save()
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process_revisions_for_item(instance, revision_data)
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return instance
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class CollectionSerializer(serializers.ModelSerializer):
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encryptionKey = CollectionEncryptionKeyField()
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accessLevel = serializers.SerializerMethodField('get_access_level_from_context')
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stoken = serializers.CharField(read_only=True)
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content = CollectionItemRevisionSerializer(many=False)
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class Meta:
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model = models.Collection
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fields = ('uid', 'version', 'accessLevel', 'encryptionKey', 'content', 'stoken')
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def get_access_level_from_context(self, obj):
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request = self.context.get('request', None)
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if request is not None:
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return obj.members.get(user=request.user).accessLevel
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return None
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def create(self, validated_data):
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"""Function that's called when this serializer creates an item"""
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revision_data = validated_data.pop('content')
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encryption_key = validated_data.pop('encryptionKey')
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instance = self.__class__.Meta.model(**validated_data)
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with transaction.atomic():
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instance.save()
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main_item = models.CollectionItem.objects.create(
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uid=None, encryptionKey=None, version=instance.version, collection=instance)
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process_revisions_for_item(main_item, revision_data)
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models.CollectionMember(collection=instance,
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user=validated_data.get('owner'),
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accessLevel=models.CollectionMember.AccessLevels.ADMIN,
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encryptionKey=encryption_key,
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).save()
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return instance
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def update(self, instance, validated_data):
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"""Function that's called when this serializer is meant to update an item"""
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revision_data = validated_data.pop('content')
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with transaction.atomic():
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main_item = instance.main_item
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# We don't have to use select_for_update here because the unique constraint on current guards against
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# the race condition. But it's a good idea because it'll lock and wait rather than fail.
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current_revision = main_item.revisions.filter(current=True).select_for_update().first()
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current_revision.current = None
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current_revision.save()
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process_revisions_for_item(main_item, revision_data)
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return instance
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