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import uuid
from base64 import b64encode, b64decode
from u1db import errors
from u1db.remote.http_target import HTTPSyncTarget
from couchdb.client import Server, Document as CouchDocument
from couchdb.http import ResourceNotFound
from leap.soledad.backends.objectstore import ObjectStore
from leap.soledad.backends.leap_backend import LeapDocument
try:
import simplejson as json
except ImportError:
import json # noqa
class CouchDatabase(ObjectStore):
"""A U1DB implementation that uses Couch as its persistence layer."""
def __init__(self, url, database, replica_uid=None, full_commit=True, session=None):
"""Create a new Couch data container."""
self._url = url
self._full_commit = full_commit
self._session = session
self._server = Server(url=self._url,
full_commit=self._full_commit,
session=self._session)
self._dbname = database
# this will ensure that transaction and sync logs exist and are
# up-to-date.
self.set_document_factory(LeapDocument)
try:
self._database = self._server[database]
except ResourceNotFound:
self._server.create(database)
self._database = self._server[database]
super(CouchDatabase, self).__init__(replica_uid=replica_uid)
#-------------------------------------------------------------------------
# implemented methods from Database
#-------------------------------------------------------------------------
def _get_doc(self, doc_id, check_for_conflicts=False):
"""Get just the document content, without fancy handling.
Conflicts do not happen on server side, so there's no need to check
for them.
"""
cdoc = self._database.get(doc_id)
if cdoc is None:
return None
has_conflicts = False
if check_for_conflicts:
has_conflicts = self._has_conflicts(doc_id)
doc = self._factory(
doc_id=doc_id,
rev=cdoc['u1db_rev'],
has_conflicts=has_conflicts)
if cdoc['u1db_json'] is not None:
doc.content = json.loads(cdoc['u1db_json'])
else:
doc.make_tombstone()
return doc
def get_all_docs(self, include_deleted=False):
"""Get all documents from the database."""
generation = self._get_generation()
results = []
for doc_id in self._database:
if doc_id == self.U1DB_DATA_DOC_ID:
continue
doc = self._get_doc(doc_id, check_for_conflicts=True)
if doc.content is None and not include_deleted:
continue
results.append(doc)
return (generation, results)
def _put_doc(self, doc):
# prepare couch's Document
cdoc = CouchDocument()
cdoc['_id'] = doc.doc_id
# we have to guarantee that couch's _rev is cosistent
old_cdoc = self._database.get(doc.doc_id)
if old_cdoc is not None:
cdoc['_rev'] = old_cdoc['_rev']
# store u1db's rev
cdoc['u1db_rev'] = doc.rev
# store u1db's content as json string
if not doc.is_tombstone():
cdoc['u1db_json'] = doc.get_json()
else:
cdoc['u1db_json'] = None
# save doc in db
self._database.save(cdoc)
def get_sync_target(self):
return CouchSyncTarget(self)
def close(self):
# TODO: fix this method so the connection is properly closed and
# test_close (+tearDown, which deletes the db) works without problems.
self._url = None
self._full_commit = None
self._session = None
#self._server = None
self._database = None
return True
def sync(self, url, creds=None, autocreate=True):
from u1db.sync import Synchronizer
from u1db.remote.http_target import CouchSyncTarget
return Synchronizer(self, CouchSyncTarget(url, creds=creds)).sync(
autocreate=autocreate)
def _initialize(self):
if self._replica_uid is None:
self._replica_uid = uuid.uuid4().hex
doc = self._factory(doc_id=self.U1DB_DATA_DOC_ID)
doc.content = { 'sync_log' : [],
'transaction_log' : [],
'conflict_log' : b64encode(json.dumps([])),
'replica_uid' : self._replica_uid }
self._put_doc(doc)
def _get_u1db_data(self):
cdoc = self._database.get(self.U1DB_DATA_DOC_ID)
content = json.loads(cdoc['u1db_json'])
self._sync_log.log = content['sync_log']
self._transaction_log.log = content['transaction_log']
self._conflict_log.log = json.loads(b64decode(content['conflict_log']))
self._replica_uid = content['replica_uid']
self._couch_rev = cdoc['_rev']
def _set_u1db_data(self):
doc = self._factory(doc_id=self.U1DB_DATA_DOC_ID)
doc.content = { 'sync_log' : self._sync_log.log,
'transaction_log' : self._transaction_log.log,
# Here, the b64 encode ensures that document content
# does not cause strange behaviour in couchdb because
# of encoding.
'conflict_log' : b64encode(json.dumps(self._conflict_log.log)),
'replica_uid' : self._replica_uid,
'_rev' : self._couch_rev}
self._put_doc(doc)
#-------------------------------------------------------------------------
# Couch specific methods
#-------------------------------------------------------------------------
def delete_database(self):
del(self._server[self._dbname])
class CouchSyncTarget(HTTPSyncTarget):
def get_sync_info(self, source_replica_uid):
source_gen, source_trans_id = self._db._get_replica_gen_and_trans_id(
source_replica_uid)
my_gen, my_trans_id = self._db._get_generation_info()
return (
self._db._replica_uid, my_gen, my_trans_id, source_gen,
source_trans_id)
def record_sync_info(self, source_replica_uid, source_replica_generation,
source_replica_transaction_id):
if self._trace_hook:
self._trace_hook('record_sync_info')
self._db._set_replica_gen_and_trans_id(
source_replica_uid, source_replica_generation,
source_replica_transaction_id)
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