A simple recursive function can be used to convert an entity (and any referents) to a nested dictionary that can be passed to simplejson
:
import datetime
import time
SIMPLE_TYPES = (int, long, float, bool, dict, basestring, list)
def to_dict(model):
output = {}
for key, prop in model.properties().iteritems():
value = getattr(model, key)
if value is None or isinstance(value, SIMPLE_TYPES):
output[key] = value
elif isinstance(value, datetime.date):
# Convert date/datetime to MILLISECONDS-since-epoch (JS "new Date()").
ms = time.mktime(value.utctimetuple()) * 1000
ms += getattr(value, 'microseconds', 0) / 1000
output[key] = int(ms)
elif isinstance(value, db.GeoPt):
output[key] = {'lat': value.lat, 'lon': value.lon}
elif isinstance(value, db.Model):
output[key] = to_dict(value)
else:
raise ValueError('cannot encode ' + repr(prop))
return output