Added json serialisation support

- Added to_json and from_json to Document (MongoEngine/mongoengine#1)
- Added to_json and from_json to QuerySet (MongoEngine/mongoengine#131)

mongoengine/queryset/queryset.py

@@ -6,6 +6,7 @@ import re
 import warnings
 
 from bson.code import Code
+from bson import json_util
 import pymongo
 from pymongo.common import validate_read_preference
 
@@ -1216,6 +1217,15 @@ class QuerySet(object):
         max_depth += 1
         return self._dereference(self, max_depth=max_depth)
 
+    def to_json(self):
+        """Converts a queryset to JSON"""
+        return json_util.dumps(self._collection_obj.find(self._query))
+
+    def from_json(self, json_data):
+        """Converts json data to unsaved objects"""
+        son_data = json_util.loads(json_data)
+        return [self._document._from_son(data) for data in son_data]
+
     @property
     def _dereference(self):
         if not self.__dereference: