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authordrebs <drebs@joselito.semvergonha.org>2013-03-07 16:34:22 -0300
committerdrebs <drebs@joselito.semvergonha.org>2013-03-07 16:34:22 -0300
commit1b1def113e6ed9b8af6897e16f0d9b4c96bbfa6b (patch)
treec34b751dde12bc92628165e8af902da54e39e898 /soledad/backends/sqlcipher.py
parent4672ec4f25daa6466b2850bea416eaf77fa90d9d (diff)
Move source files to subfolder.
Diffstat (limited to 'soledad/backends/sqlcipher.py')
-rw-r--r--soledad/backends/sqlcipher.py163
1 files changed, 163 insertions, 0 deletions
diff --git a/soledad/backends/sqlcipher.py b/soledad/backends/sqlcipher.py
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+"""A U1DB backend that uses SQLCipher as its persistence layer."""
+
+import os
+from pysqlcipher import dbapi2
+import time
+
+from leap import util
+from u1db.backends import sqlite_backend
+util.logger.debug(
+ "Monkey-patching u1db.backends.sqlite_backend with pysqlcipher.dbapi2..."
+)
+sqlite_backend.dbapi2 = dbapi2
+
+from u1db import (
+ errors,
+)
+
+from leap.soledad.backends.leap_backend import LeapDocument
+
+
+def open(path, password, create=True, document_factory=None, soledad=None):
+ """Open a database at the given location.
+
+ Will raise u1db.errors.DatabaseDoesNotExist if create=False and the
+ database does not already exist.
+
+ :param path: The filesystem path for the database to open.
+ :param create: True/False, should the database be created if it doesn't
+ already exist?
+ :param document_factory: A function that will be called with the same
+ parameters as Document.__init__.
+ :return: An instance of Database.
+ """
+ return SQLCipherDatabase.open_database(
+ path, password, create=create, document_factory=document_factory,
+ soledad=soledad)
+
+
+class DatabaseIsNotEncrypted(Exception):
+ """
+ Exception raised when trying to open non-encrypted databases.
+ """
+ pass
+
+
+class SQLCipherDatabase(sqlite_backend.SQLitePartialExpandDatabase):
+ """A U1DB implementation that uses SQLCipher as its persistence layer."""
+
+ _index_storage_value = 'expand referenced encrypted'
+
+ @classmethod
+ def set_pragma_key(cls, db_handle, key):
+ db_handle.cursor().execute("PRAGMA key = '%s'" % key)
+
+ def __init__(self, sqlite_file, password, document_factory=None,
+ soledad=None):
+ """Create a new sqlcipher file."""
+ self._check_if_db_is_encrypted(sqlite_file)
+ self._db_handle = dbapi2.connect(sqlite_file)
+ SQLCipherDatabase.set_pragma_key(self._db_handle, password)
+ self._real_replica_uid = None
+ self._ensure_schema()
+ self._soledad = soledad
+
+ def factory(doc_id=None, rev=None, json='{}', has_conflicts=False,
+ encrypted_json=None, syncable=True):
+ return LeapDocument(doc_id=doc_id, rev=rev, json=json,
+ has_conflicts=has_conflicts,
+ encrypted_json=encrypted_json,
+ syncable=syncable, soledad=self._soledad)
+ self.set_document_factory(factory)
+
+ def _check_if_db_is_encrypted(self, sqlite_file):
+ if not os.path.exists(sqlite_file):
+ return
+ else:
+ try:
+ # try to open an encrypted database with the regular u1db
+ # backend should raise a DatabaseError exception.
+ sqlite_backend.SQLitePartialExpandDatabase(sqlite_file)
+ raise DatabaseIsNotEncrypted()
+ except dbapi2.DatabaseError:
+ pass
+
+ @classmethod
+ def _open_database(cls, sqlite_file, password, document_factory=None,
+ soledad=None):
+ if not os.path.isfile(sqlite_file):
+ raise errors.DatabaseDoesNotExist()
+ tries = 2
+ while True:
+ # Note: There seems to be a bug in sqlite 3.5.9 (with python2.6)
+ # where without re-opening the database on Windows, it
+ # doesn't see the transaction that was just committed
+ db_handle = dbapi2.connect(sqlite_file)
+ SQLCipherDatabase.set_pragma_key(db_handle, password)
+ c = db_handle.cursor()
+ v, err = cls._which_index_storage(c)
+ db_handle.close()
+ if v is not None:
+ break
+ # possibly another process is initializing it, wait for it to be
+ # done
+ if tries == 0:
+ raise err # go for the richest error?
+ tries -= 1
+ time.sleep(cls.WAIT_FOR_PARALLEL_INIT_HALF_INTERVAL)
+ return SQLCipherDatabase._sqlite_registry[v](
+ sqlite_file, password, document_factory=document_factory,
+ soledad=soledad)
+
+ @classmethod
+ def open_database(cls, sqlite_file, password, create, backend_cls=None,
+ document_factory=None, soledad=None):
+ """Open U1DB database using SQLCipher as backend."""
+ try:
+ return cls._open_database(sqlite_file, password,
+ document_factory=document_factory,
+ soledad=soledad)
+ except errors.DatabaseDoesNotExist:
+ if not create:
+ raise
+ if backend_cls is None:
+ # default is SQLCipherPartialExpandDatabase
+ backend_cls = SQLCipherDatabase
+ return backend_cls(sqlite_file, password,
+ document_factory=document_factory,
+ soledad=soledad)
+
+ def sync(self, url, creds=None, autocreate=True):
+ """
+ Synchronize encrypted documents with remote replica exposed at url.
+ """
+ from u1db.sync import Synchronizer
+ from leap.soledad.backends.leap_backend import LeapSyncTarget
+ return Synchronizer(
+ self,
+ LeapSyncTarget(url,
+ creds=creds,
+ soledad=self._soledad)).sync(autocreate=autocreate)
+
+ def _extra_schema_init(self, c):
+ c.execute(
+ 'ALTER TABLE document '
+ 'ADD COLUMN syncable BOOL NOT NULL DEFAULT TRUE')
+
+ def _put_and_update_indexes(self, old_doc, doc):
+ super(SQLCipherDatabase, self)._put_and_update_indexes(old_doc, doc)
+ c = self._db_handle.cursor()
+ c.execute('UPDATE document SET syncable=? WHERE doc_id=?',
+ (doc.syncable, doc.doc_id))
+
+ def _get_doc(self, doc_id, check_for_conflicts=False):
+ doc = super(SQLCipherDatabase, self)._get_doc(doc_id,
+ check_for_conflicts)
+ if doc:
+ c = self._db_handle.cursor()
+ c.execute('SELECT syncable FROM document WHERE doc_id=?',
+ (doc.doc_id,))
+ doc.syncable = bool(c.fetchone()[0])
+ return doc
+
+sqlite_backend.SQLiteDatabase.register_implementation(SQLCipherDatabase)