cola/serializer.py

   1 """Provides a serializer for arbitrary Python objects"""
   2 import jsonpickle
   3 jsonpickle.set_encoder_options('simplejson', indent=4)
   4
   5 from cola import utils
   6
   7 handlers = {}
   8
   9
  10 def save(obj, path):
  11     utils.write(path, encode(obj))
  12
  13
  14 def load(path):
  15     import jsonpickle
  16     return decode(utils.slurp(path))
  17
  18
  19 def clone(obj):
  20     # Go in and out of encode/decode to return a clone
  21     return decode(encode(obj))
  22
  23
  24 def encode(obj):
  25     handler = _gethandler(obj)
  26     if handler:
  27         handler.pre_encode_hook()
  28     jsonstr = jsonpickle.encode(obj)
  29     if handler:
  30         handler.post_encode_hook()
  31     return jsonstr
  32
  33
  34 def decode(jsonstr):
  35     obj = jsonpickle.decode(jsonstr)
  36     handler = _gethandler(obj)
  37     if handler:
  38         handler.post_decode_hook()
  39     return obj
  40
  41
  42 def _gethandler(obj):
  43     cls = type(obj)
  44     # Allow base classes to provide a serialization handlers
  45     # for their subclasses
  46     if hasattr(cls, 'mro'):
  47         for supercls in cls.mro():
  48             if supercls in handlers:
  49                 return handlers[supercls](obj)
  50     if cls in handlers:
  51         return handlers[cls](obj)
  52     return None