EDIT:
irgendwas stimmt mit mein copy & paste nicht?
nochmal EDIT:
bug gefixt
Code: Alles auswählen
#!/usr/bin/env python3
import sqlite3
import pickle
import collections
class SqlDict(collections.MutableMapping):
def __init__(self, db_path=':memory:',
will_pickle=True,
debug=False):
if will_pickle:
will_pickle = lambda i: not isinstance(i, (str, int, float, bool, None.__class__))
self._sql_conn = conn = sqlite3.connect(db_path)
self.will_pickle = will_pickle
self.debug = debug
self._execute('''
CREATE TABLE IF NOT EXISTS dictitem
(key BLOB,
value BLOB,
PRIMARY KEY(key))''')
def __getitem__(self, key):
fetched = self._execute('select value from dictitem where key=?', [key]).fetchone()
if fetched is None:
raise ValueError('key "{0}" not found'.format(key))
return self._load(fetched[0])
def __setitem__(self, key, value):
self._execute('insert or replace into dictitem values (?, ?)', [key, value])
def __delitem__(self, key):
self[key]
self._execute('delete from dictitem where key=?', [key])
def __len__(self):
return self._execute('select count(*) from dictitem').fetchone()[0]
def __iter__(self):
cursor = self._execute('select key from dictitem')
while True:
fetched = cursor.fetchone()
if not fetched:
break
yield fetched[0]
def close(self):
self.sync()
self._sql_conn.close()
def sync(self):
self._sql_conn.commit()
def _load(self, arg):
if isinstance(arg, bytes):
return pickle.loads(arg)
return arg
def _dump(self, arg):
if self.will_pickle and self.will_pickle(arg):
return pickle.dumps(arg)
return arg
def _execute(self, query, args=[]):
cursor = self._sql_conn.cursor()
if self.will_pickle:
args = list(map(self._dump, args))
if self.debug:
print('SQL executing:', query, args)
cursor.execute(query, args)
return cursor
if __name__ == '__main__':
d = SqlDict()
d['bla'] = range(8)
import shelve
s = shelve.Shelf(SqlDict('/tmp/test', will_pickle=False, debug=True), writeback=True)
s['hype hyper'] = list(d.keys())
s.update(d)
s['bla'] = list(s['bla'])
s['bla'].append('write back works!')
print(s['bla'][-1])
for key in s:
print(key)
d.close()
s.close()
