1- # -*- coding: utf-8 -*-
2-
31"""simple key-value cache with transparent payload compression and expiration
42
53Taken from http://bitbucket.org/reece/rcore/
64"""
75
86import logging
9- import os
107import pickle
118import sqlite3
129import zlib
@@ -29,7 +26,7 @@ def val_from(pobj, compress):
2926 return pickle .loads (zlib .decompress (pobj ) if compress else pobj )
3027
3128
32- class SQLiteCache ( object ) :
29+ class SQLiteCache :
3330 ############################################################################
3431 ## Exposed methods
3532 def __init__ (self , db_path , compress_values = True ):
@@ -46,16 +43,14 @@ def expire(self, age):
4643 ## Special Python methods
4744
4845 def __str__ (self ):
49- return "SQLiteCache(db_path={self._db_path},compress_values={self.compress_values})" .format (
50- self = self
51- )
46+ return f"SQLiteCache(db_path={ self ._db_path } ,compress_values={ self .compress_values } )"
5247
5348 def __dir__ (self ):
5449 self ._logger .debug ("__dir__()" )
5550 return [key_from (row [0 ]) for row in self ._execute ("SELECT key FROM cache" , [])]
5651
5752 def __getitem__ (self , key ):
58- self ._logger .debug ("__getitem__({key})" . format ( key = key ) )
53+ self ._logger .debug (f "__getitem__({ key } )" )
5954 cur = self ._execute ("SELECT value,value_compressed FROM cache WHERE key = ?" , [key_to (key )])
6055 row = cur .fetchone ()
6156 if row is None :
@@ -64,20 +59,20 @@ def __getitem__(self, key):
6459
6560 def __setitem__ (self , key , value ):
6661 db_val = val_to (value , self .compress_values )
67- self ._logger .debug ("__setitem__({key},({vlen } bytes))" . format ( key = key , vlen = len ( db_val )) )
62+ self ._logger .debug (f "__setitem__({ key } ,({ len ( db_val ) } bytes))" )
6863 self ._execute (
6964 "INSERT OR REPLACE INTO cache (key,value_compressed,value) VALUES (?,?,?)" ,
7065 [key_to (key ), self .compress_values , db_val ],
7166 )
7267
7368 def __delitem__ (self , key ):
74- self ._logger .debug ("__delitem__({key})" . format ( key = key ) )
69+ self ._logger .debug (f "__delitem__({ key } )" )
7570 cur = self ._execute ("DELETE FROM cache WHERE key = ?" , [key_to (key )])
7671 if cur .rowcount == 0 :
7772 raise KeyError (key )
7873
7974 def __contains__ (self , key ):
80- self ._logger .debug ("__contains__({key})" . format ( key = key ) )
75+ self ._logger .debug (f "__contains__({ key } )" )
8176 return self ._fetch1v (
8277 "SELECT EXISTS(SELECT 1 FROM cache WHERE key=? LIMIT 1)" , [key_to (key )]
8378 )
@@ -110,11 +105,7 @@ def _get_schema_version(self):
110105
111106 def _execute (self , query , params = []):
112107 cur = self ._con .cursor ()
113- self ._logger .debug (
114- "executing query <{query}> with params <{nvars} vars>" .format (
115- query = query , nvars = len (params )
116- )
117- )
108+ self ._logger .debug (f"executing query <{ query } > with params <{ len (params )} vars>" )
118109 cur .execute (query , params )
119110 return cur
120111
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