mygpo/core/proxy.py

   1 from abc import ABCMeta
   2
   3 from couchdbkit.ext.django.schema import DocumentMeta
   4
   5
   6
   7 class DocumentABCMeta(ABCMeta, DocumentMeta):
   8     """ Meta class must be subclass of all parents' meta classes """
   9     pass
  10
  11
  12
  13 def proxy_object(obj, **kwargs):
  14     """ Proxies an object to make it arbitrarily modifiable
  15
  16     It is not possible to add arbitrary values to an couchdbkit Document,
  17     because all values have to fit the schema and have to be JSON serializable
  18     """
  19
  20     class ProxyObject(object):
  21         """ Proxy for obj that can have properties of arbitrary type """
  22
  23         # ensure that proxied objects can be proxied again
  24         __metaclass__ = DocumentABCMeta
  25
  26         def __init__(self, obj, **kwargs):
  27             self.obj = obj
  28
  29             for key, val in kwargs.items():
  30                 setattr(self, key, val)
  31
  32
  33         def __getattr__(self, attr):
  34             return getattr(self.obj, attr)
  35
  36
  37         def __eq__(self, other):
  38             # if "other" is of the same type as proxied obj, compare directly
  39             if isinstance(other, ProxyObject):
  40                 return self.obj == other.obj
  41
  42             else:
  43                 return self.obj == other
  44
  45         def __hash__(self):
  46             return hash(self.obj)
  47
  48
  49     cls = obj.__class__
  50     cls.register(ProxyObject)
  51
  52     return ProxyObject(obj, **kwargs)