flask application: trying to jsonify a dictionary

Question

Background Info

I'm trying to write my first flask / python REST API. So far, I have a GET that connects to a redis database and tries to convert a dictionary to json... and then return those results.

Problem

When I try to call jsonify on my dict object, it fails with the following error:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/lib/python3.6/site-packages/flask/app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/lib/python3.6/site-packages/flask/app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/lib/python3.6/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/usr/lib/python3.6/site-packages/flask/app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/lib/python3.6/site-packages/flask/app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/var/www/localhost/htdocs/widgets/widgets.py", line 51, in get_profile
    return jsonify(res_dict)
  File "/usr/lib/python3.6/site-packages/flask/json.py", line 263, in jsonify
    (dumps(data, indent=indent, separators=separators), '\n'),
  File "/usr/lib/python3.6/site-packages/flask/json.py", line 123, in dumps
    rv = _json.dumps(obj, **kwargs)
  File "/usr/lib/python3.6/json/__init__.py", line 238, in dumps
    **kw).encode(obj)
  File "/usr/lib/python3.6/json/encoder.py", line 201, in encode
    chunks = list(chunks)
  File "/usr/lib/python3.6/json/encoder.py", line 430, in _iterencode
    yield from _iterencode_dict(o, _current_indent_level)
  File "/usr/lib/python3.6/json/encoder.py", line 376, in _iterencode_dict
    raise TypeError("key " + repr(key) + " is not a string")
TypeError: key b'email1' is not a string

The code looks like this:

 20 def get_db_profile(mailbox):
 21     """ connects to redis and queries for profile """
 22     try:
 23         my_redis = redis.Redis(connection_pool=POOL)
 24         response = my_redis.hgetall(55555)
 25         logging.info(response.keys())
 26         logging.info(response.items())
 27         #response = '123455555'
 28         return response
 29     except Exception as ex:
 30         return "Error:", ex

47 @application.route("/widgets/api/<int:mailbox>", methods=['GET'])
48 def get_profile(mailbox):
49     res_dict = get_db_profile(mailbox)
50 #    return application.response_class(jsonify(res_dict), content_type='application/json')
51     return jsonify(res_dict)
52 #    return '12345'
53

I added some logging as you can see on line 25 to see what the keys() look like. this is what I see in the log file:

lab-1:/var/www/localhost/htdocs/widgets# cat /tmp/widgets.log
root - INFO - dict_keys([b'email1', b'email2'])

REDIS Data

This is how I created the redis data:

127.0.0.1:6379[5]> hmset 55555 email1 johndoe@hotmail.com email2 jd@yahoo.com
OK
127.0.0.1:6379[5]>

Questions

Should i be able to convert from dict object to json string? What is the 'b' in the log files?

lab-1:/var/www/localhost/htdocs/widgets# cat /tmp/widgets.log
root - INFO - dict_keys([b'email1', b'email2'])
root - INFO - dict_items([(b'email1', b'johndoe@hotmail.com'), (b'email2', b'jd@yahoo.com')])

How do I send back a proper JSON response?

EDIT 1

I found this question/answer: How to parse python b' string containing dict and based on that I tried to change my logic to look like this:

47 @application.route("/pvmailprofiles/api/<int:mailbox>", methods=['GET'])
48 def get_profile(mailbox):
49     res_dict = get_db_profile(mailbox)
50 #    return application.response_class(jsonify(res_dict), content_type='application/json')
51     #return jsonify(res_dict)
52     return res_dict[b'email1']
53 #    return '12345'
54

Line 52 - you can see that as a test I've hardcoded the 'b' and then the key name. And it works - it returns the specific email address. But I need to find a way to "just" convert everything to json and return to callee.

Answer 1

Have you tried first importing json like so

import json

and then doing

json.dumps(myDict)

and then to load it again if needed.

json.loads(response.text)