json.loads allows duplicate keys in a dictionary, overwriting the first value

Question

>>> raw_post_data = request.raw_post_data
>>> print raw_post_data
{\"group\":{\"groupId\":\"2\", \"groupName\":\"GroupName\"}, \"members\":{\"1\":{         


        

Answer 1

Alternatively if you want to catch all the duplicate keys (per level) you can use a collections.Counter

from collections import Counter

class KeyWatcher(dict):

    def __init__(self, *args):
        duplicates = [d for d,i in Counter([pair[0] for pair in args[0]]).items() if i > 0]
        if duplicates:
            raise KeyError("Can't add duplicate keys {} to a json message".format(duplicates))
        self.update(*args[0])

json.loads(raw_post_data, object_pairs_hook=KeyWatcher)