sfa/util/storage.py

   1 import os
   2 from sfa.util.xml import XML
   3
   4
   5 class SimpleStorage(dict):
   6     """
   7     Handles storing and loading python dictionaries. The storage file created
   8     is a string representation of the native python dictionary.
   9     """
  10     db_filename = None
  11     type = 'dict'
  12
  13     def __init__(self, db_filename, db=None):
  14         if db is None:
  15             db = {}
  16         dict.__init__(self, db)
  17         self.db_filename = db_filename
  18
  19     def load(self):
  20         if os.path.exists(self.db_filename) and os.path.isfile(self.db_filename):
  21             db_file = open(self.db_filename, 'r')
  22             dict.__init__(self, eval(db_file.read()))
  23         elif os.path.exists(self.db_filename) and not os.path.isfile(self.db_filename):
  24             raise IOError('%s exists but is not a file. please remove it and try again'
  25                           % self.db_filename)
  26         else:
  27             self.write()
  28             self.load()
  29
  30     def write(self):
  31         db_file = open(self.db_filename, 'w')
  32         db_file.write(str(self))
  33         db_file.close()
  34
  35     def sync(self):
  36         self.write()
  37
  38
  39 class XmlStorage(SimpleStorage):
  40     """
  41     Handles storing and loading python dictionaries. The storage file created
  42     is a xml representation of the python dictionary.
  43     """
  44     db_filename = None
  45     type = 'xml'
  46
  47     def load(self):
  48         """
  49         Parse an xml file and store it as a dict
  50         """
  51         if os.path.exists(self.db_filename) and os.path.isfile(self.db_filename):
  52             xml = XML(self.db_filename)
  53             dict.__init__(self, xml.todict())
  54         elif os.path.exists(self.db_filename) and not os.path.isfile(self.db_filename):
  55             raise IOError('%s exists but is not a file. please remove it and try again'
  56                           % self.db_filename)
  57         else:
  58             self.write()
  59             self.load()
  60
  61     def write(self):
  62         xml = XML()
  63         xml.parseDict(self)
  64         db_file = open(self.db_filename, 'w')
  65         db_file.write(data.toprettyxml())
  66         db_file.close()
  67
  68     def sync(self):
  69         self.write()