json.loads allows duplicate keys in a dictionary, overwriting the first value
json, python
Solution
The rfc 4627 for `application/json` media type recommends unique keys but it doesn't forbid them explicitly:
The names within an object SHOULD be unique.
From rfc 2119:
SHOULD This word, or the adjective "RECOMMENDED", mean that there may exist valid reasons in particular circumstances to ignore a particular item, but the full implications must be understood and carefully weighed before choosing a different course.
import json
def dict_raise_on_duplicates(ordered_pairs):
"""Reject duplicate keys."""
d = {}
for k, v in ordered_pairs:
if k in d:
raise ValueError("duplicate key: %r" % (k,))
else:
d[k] = v
return d
json.loads(raw_post_data, object_pairs_hook=dict_raise_on_duplicates)
# -> ValueError: duplicate key: u'1'
Problem
``` >>> raw_post_data = request.raw_post_data >>> print raw_post_data {"group":{"groupId":"2", "groupName":"GroupName"}, "members":{"1":{"firstName":"fName","lastName":"LName","address":"address"},"1": {"firstName":"f_Name","lastName":"L_Name","address":"_address"}}} >>> create_request = json.loads(raw_post_data) >>> print create_request {u'group': {u'groupName': u'GroupName', u'groupId': u'2'}, u'members': {u'1': {u'lastName': u'L_Name', u'firstName': u'f_Name', u'address': u'_address'}}} ``` As you can see members with key '1' is overwritten when I use `json.dumps()` Is there any way to catch it as exception in python, saying found duplicate keys in request from client ?