Demo/classes/Dbm.py

   1 # A wrapper around the (optional) built-in class dbm, supporting keys
   2 # and values of almost any type instead of just string.
   3 # (Actually, this works only for keys and values that can be read back
   4 # correctly after being converted to a string.)
   5
   6
   7 class Dbm:
   8
   9         def __init__(self, filename, mode, perm):
  10                 import dbm
  11                 self.db = dbm.open(filename, mode, perm)
  12
  13         def __repr__(self):
  14                 s = ''
  15                 for key in self.keys():
  16                         t = `key` + ': ' + `self[key]`
  17                         if s: t = ', ' + t
  18                         s = s + t
  19                 return '{' + s + '}'
  20
  21         def __len__(self):
  22                 return len(self.db)
  23
  24         def __getitem__(self, key):
  25                 return eval(self.db[`key`])
  26
  27         def __setitem__(self, key, value):
  28                 self.db[`key`] = `value`
  29
  30         def __delitem__(self, key):
  31                 del self.db[`key`]
  32
  33         def keys(self):
  34                 res = []
  35                 for key in self.db.keys():
  36                         res.append(eval(key))
  37                 return res
  38
  39         def has_key(self, key):
  40                 return self.db.has_key(`key`)
  41
  42
  43 def test():
  44         d = Dbm('@dbm', 'rw', 0600)
  45         print d
  46         while 1:
  47                 try:
  48                         key = input('key: ')
  49                         if d.has_key(key):
  50                                 value = d[key]
  51                                 print 'currently:', value
  52                         value = input('value: ')
  53                         if value == None:
  54                                 del d[key]
  55                         else:
  56                                 d[key] = value
  57                 except KeyboardInterrupt:
  58                         print ''
  59                         print d
  60                 except EOFError:
  61                         print '[eof]'
  62                         break
  63         print d
  64
  65
  66 test()