geni/util/storage.py

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