import logging
from sqlite3 import OperationalError
from .cursors import *
logger = logging.getLogger(__name__)
_DB_SCHEMA_VER = 3
_CREATION_SCRIPT = """
CREATE TABLE metadata (
"key" VARCHAR(64) NOT NULL,
value VARCHAR,
PRIMARY KEY ("key")
);
CREATE TABLE nodes (
id VARCHAR(50) NOT NULL,
type VARCHAR(15),
name VARCHAR(256),
description VARCHAR(500),
created DATETIME,
modified DATETIME,
updated DATETIME,
status VARCHAR(9),
PRIMARY KEY (id),
UNIQUE (id),
CHECK (status IN ('AVAILABLE', 'TRASH', 'PURGED', 'PENDING'))
);
CREATE TABLE labels (
id VARCHAR(50) NOT NULL,
name VARCHAR(256) NOT NULL,
PRIMARY KEY (id, name),
FOREIGN KEY(id) REFERENCES nodes (id)
);
CREATE TABLE files (
id VARCHAR(50) NOT NULL,
md5 VARCHAR(32),
size BIGINT,
PRIMARY KEY (id),
UNIQUE (id),
FOREIGN KEY(id) REFERENCES nodes (id)
);
CREATE TABLE parentage (
parent VARCHAR(50) NOT NULL,
child VARCHAR(50) NOT NULL,
PRIMARY KEY (parent, child),
FOREIGN KEY(parent) REFERENCES folders (id),
FOREIGN KEY(child) REFERENCES nodes (id)
);
CREATE INDEX ix_nodes_names ON nodes(name);
PRAGMA user_version = %i;
""" % _DB_SCHEMA_VER
_prop_table = """
CREATE TABLE properties (
id VARCHAR(50) NOT NULL,
owner TEXT NOT NULL,
key TEXT NOT NULL,
value TEXT,
PRIMARY KEY (id),
FOREIGN KEY(id) REFERENCES nodes (id)
);
"""
_CREATION_SCRIPT += _prop_table
_GEN_DROP_TABLES_SQL = \
'SELECT "DROP TABLE " || name || ";" FROM sqlite_master WHERE type == "table"'
_migrations = []
"""list of all migrations from index -> index+1"""
[docs]def migration(func):
_migrations.append(func)
return func
@migration
def _0_to_1(conn):
conn.executescript(
'ALTER TABLE nodes ADD updated DATETIME;'
'ALTER TABLE nodes ADD description VARCHAR(500);'
'PRAGMA user_version = 1;'
)
conn.commit()
@migration
def _1_to_2(conn):
conn.executescript(
'DROP TABLE IF EXISTS folders;'
'CREATE INDEX IF NOT EXISTS ix_nodes_names ON nodes(name);'
'REINDEX;'
'PRAGMA user_version = 2;'
)
conn.commit()
@migration
def _2_to_3(conn):
conn.executescript(
_prop_table +
'PRAGMA user_version = 3;'
);
[docs]class SchemaMixin(object):
[docs] def init(self):
try:
self.create_tables()
except OperationalError:
pass
with cursor(self._conn) as c:
c.execute('PRAGMA user_version;')
r = c.fetchone()
ver = r[0]
logger.info('DB schema version is %i.' % ver)
if _DB_SCHEMA_VER > ver:
self._migrate(ver)
self.KeyValueStorage = _KeyValueStorage(self._conn)
[docs] def create_tables(self):
self._conn.executescript(_CREATION_SCRIPT)
self._conn.commit()
def _migrate(self, version):
for i, migration in enumerate(_migrations[version:]):
v = i + version
logger.info('Migrating from schema version %i to %i' % (v, v + 1))
migration(self._conn)
[docs] def drop_all(self):
drop_sql = []
with cursor(self._conn) as c:
c.execute(_GEN_DROP_TABLES_SQL)
dt = c.fetchone()
while dt:
drop_sql.append(dt[0])
dt = c.fetchone()
with mod_cursor(self._conn) as c:
for drop in drop_sql:
c.execute(drop)
self._conn.commit()
logger.info('Dropped all tables.')
return True
class _KeyValueStorage(object):
def __init__(self, conn):
self.conn = conn
def __getitem__(self, key: str):
with cursor(self.conn) as c:
c.execute('SELECT value FROM metadata WHERE key = (?)', [key])
r = c.fetchone()
if r:
return r['value']
else:
raise KeyError
def __setitem__(self, key: str, value: str):
with mod_cursor(self.conn) as c:
c.execute('INSERT OR REPLACE INTO metadata VALUES (?, ?)', [key, value])
# def __len__(self):
# return self.Session.query(Metadate).count()
def get(self, key: str, default: str = None):
with cursor(self.conn) as c:
c.execute('SELECT value FROM metadata WHERE key == ?', [key])
r = c.fetchone()
return r['value'] if r else default
def update(self, dict_: dict):
for key in dict_.keys():
self.__setitem__(key, dict_[key])