magic-wormhole/src/wormhole/server/database.py
2016-05-16 22:04:25 -07:00

43 lines
1.3 KiB
Python

import os, sys
import sqlite3
from pkg_resources import resource_string
class DBError(Exception):
pass
def get_schema(version):
schema_bytes = resource_string("wormhole.server",
"db-schemas/v%d.sql" % version)
return schema_bytes.decode("utf-8")
def get_db(dbfile, stderr=sys.stderr):
"""Open or create the given db file. The parent directory must exist.
Returns the db connection object, or raises DBError.
"""
must_create = not os.path.exists(dbfile)
try:
db = sqlite3.connect(dbfile)
except (EnvironmentError, sqlite3.OperationalError) as e:
raise DBError("Unable to create/open db file %s: %s" % (dbfile, e))
db.row_factory = sqlite3.Row
VERSION = 2
if must_create:
schema = get_schema(VERSION)
db.executescript(schema)
db.execute("INSERT INTO version (version) VALUES (?)", (VERSION,))
db.commit()
try:
version = db.execute("SELECT version FROM version").fetchone()[0]
except sqlite3.DatabaseError as e:
# this indicates that the file is not a compatible database format.
# Perhaps it was created with an old version, or it might be junk.
raise DBError("db file is unusable: %s" % e)
if version != VERSION:
raise DBError("Unable to handle db version %s" % version)
return db