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# -*- coding: utf-8 -*-
# fetch.py
# Copyright (C) 2015 LEAP
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 json
from twisted.internet import defer
from twisted.internet import threads
from leap.soledad.client.events import SOLEDAD_SYNC_RECEIVE_STATUS
from leap.soledad.client.events import emit_async
from leap.soledad.client.http_target.support import RequestBody
from leap.soledad.common.log import getLogger
from leap.soledad.client._crypto import is_symmetrically_encrypted
from leap.soledad.common.document import Document
from leap.soledad.common.l2db import errors
from leap.soledad.client import crypto as old_crypto
from . import fetch_protocol
logger = getLogger(__name__)
class HTTPDocFetcher(object):
"""
Handles Document fetching from Soledad server, using HTTP as transport.
Steps:
* Prepares metadata by asking server for one document
* Fetch the total on response and prepare to ask all remaining
* (async) Documents will come encrypted.
So we parse, decrypt and insert locally as they arrive.
"""
# The uuid of the local replica.
# Any class inheriting from this one should provide a meaningful attribute
# if the sync status event is meant to be used somewhere else.
uuid = 'undefined'
userid = 'undefined'
@defer.inlineCallbacks
def _receive_docs(self, last_known_generation, last_known_trans_id,
ensure_callback, sync_id):
new_generation = last_known_generation
new_transaction_id = last_known_trans_id
# Acts as a queue, ensuring line order on async processing
# as `self._insert_doc_cb` cant be run concurrently or out of order.
# DeferredSemaphore solves the concurrency and its implementation uses
# a queue, solving the ordering.
# FIXME: Find a proper solution to avoid surprises on Twisted changes
self.semaphore = defer.DeferredSemaphore(1)
metadata = yield self._fetch_all(
last_known_generation, last_known_trans_id,
sync_id)
number_of_changes, ngen, ntrans = self._parse_metadata(metadata)
# wait for pending inserts
yield self.semaphore.acquire()
if ngen:
new_generation = ngen
new_transaction_id = ntrans
defer.returnValue([new_generation, new_transaction_id])
def _fetch_all(self, last_known_generation,
last_known_trans_id, sync_id):
# add remote replica metadata to the request
body = RequestBody(
last_known_generation=last_known_generation,
last_known_trans_id=last_known_trans_id,
sync_id=sync_id,
ensure=self._ensure_callback is not None)
self._received_docs = 0
# build a stream reader with _doc_parser as a callback
body_reader = fetch_protocol.build_body_reader(self._doc_parser)
# start download stream
return self._http_request(
self._url,
method='POST',
body=str(body),
content_type='application/x-soledad-sync-get',
body_reader=body_reader)
@defer.inlineCallbacks
def _doc_parser(self, doc_info, content, total):
"""
Insert a received document into the local replica, decrypting
if necessary. The case where it's not decrypted is when a doc gets
inserted from Server side with a GPG encrypted content.
:param doc_info: Dictionary representing Document information.
:type doc_info: dict
:param content: The Document's content.
:type idx: str
:param total: The total number of operations.
:type total: int
"""
yield self.semaphore.run(self.__atomic_doc_parse, doc_info, content,
total)
@defer.inlineCallbacks
def __atomic_doc_parse(self, doc_info, content, total):
doc = Document(doc_info['id'], doc_info['rev'], content)
if is_symmetrically_encrypted(content):
content = (yield self._crypto.decrypt_doc(doc)).getvalue()
elif old_crypto.is_symmetrically_encrypted(doc):
content = self._deprecated_crypto.decrypt_doc(doc)
doc.set_json(content)
# TODO insert blobs here on the blob backend
# FIXME: This is wrong. Using the very same SQLite connection object
# from multiple threads is dangerous. We should bring the dbpool here
# or find an alternative. Deferring to a thread only helps releasing
# the reactor for other tasks as this is an IO intensive call.
yield threads.deferToThread(self._insert_doc_cb,
doc, doc_info['gen'], doc_info['trans_id'])
self._received_docs += 1
user_data = {'uuid': self.uuid, 'userid': self.userid}
_emit_receive_status(user_data, self._received_docs, total=total)
def _parse_metadata(self, metadata):
"""
Parse the response from the server containing the sync metadata.
:param response: Metadata as string
:type response: str
:return: (number_of_changes, new_gen, new_trans_id)
:rtype: tuple
"""
try:
metadata = json.loads(metadata)
# make sure we have replica_uid from fresh new dbs
if self._ensure_callback and 'replica_uid' in metadata:
self._ensure_callback(metadata['replica_uid'])
return (metadata['number_of_changes'], metadata['new_generation'],
metadata['new_transaction_id'])
except (ValueError, KeyError):
raise errors.BrokenSyncStream('Metadata parsing failed')
def _emit_receive_status(user_data, received_docs, total):
content = {'received': received_docs, 'total': total}
emit_async(SOLEDAD_SYNC_RECEIVE_STATUS, user_data, content)
if received_docs % 20 == 0:
msg = "%d/%d" % (received_docs, total)
logger.debug("Sync receive status: %s" % msg)
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