Flask-jwt error with Flask-restful if request contain JSON

Question

I am developing a RESTful API using Flask-restful and Flask-jwt. When I use @jwt_required() for any endpoint and I send a request containing JSON data, I do not get the error message JSON I specify. If I remove the JSON data, the request is handled properly.

Here is the Code:

@jwt_required()
def put(self, user_id):
    user = UserModel.find_by_id(user_id)        
    if user is None:
        return {"message": "User not found!"}, 404

Here is the Postman request:

PUT /user/2 HTTP/1.1
Host: 127.0.0.1:5000
Content-Type: application/json
Authorization: JWT xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Cache-Control: no-cache

{
  "backdrop_image": "Sora"
}

And the server log:

2017-10-25 18:31:06,256 INFO sqlalchemy.engine.base.Engine (2, 1, 0)
2017-10-25 18:31:06,259 INFO sqlalchemy.engine.base.Engine ROLLBACK
127.0.0.1 - - [25/Oct/2017 18:31:06] "PUT /user/2 HTTP/1.1" 404 -

If I remove the JSON:

PUT /user/2 HTTP/1.1
Host: 127.0.0.1:5000
Content-Type: application/json
Authorization: JWT xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Cache-Control: no-cache

I get the expected response:

{
    "message": "User not found!"
}

Here is the method being called:

@classmethod
    def find_by_id(cls, _id):
        return cls.query.filter_by(id = _id).first()

Update

I found out that I get No handlers could be found for logger "flask_jwt" for the 1st request

Can you comment `user = UserModel.find_by_id(user_id)` and then try again and see if it works? I just created a sample app and I don't face such issue, so most probably you are using something else also in your configuration — Tarun Lalwani, Oct 28 '17 at 08:25
`user` is `None` in both cases and no exceptions happen on this line. Also, when I print any string after this line, it is printed normally. The issue only happens when there is JSON data in the request — Mohamed_AbdAllah, Oct 29 '17 at 00:06
As I said I created a code to replicate and it works fine. So you need to provide a minimum git repo to reproduce the issue — Tarun Lalwani, Oct 29 '17 at 05:42
Did you use JWT? This request requires a JWT token. If I remove JWT, it works fine. — Mohamed_AbdAllah, Oct 29 '17 at 11:32
@classmethod def find_by_id(cls, _id): return cls.query.filter_by(id = _id).first() — Mohamed_AbdAllah, Oct 29 '17 at 11:38
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/157738/discussion-between-tarun-lalwani-and-mohamed-abdallah). — Tarun Lalwani, Oct 29 '17 at 11:45
Are you passing 'username' or 'email' in your jwt /auth endpoint? and does it match the fields in your database? — 8oh8, Sep 23 '18 at 20:59

score 0 · Answer 1 · answered Nov 03 '17 at 06:51

So I ran this in different possible combination and the issue cannot be replicated. I user below server file

from flask import Flask
from flask_jwt import JWT, jwt_required, current_identity
from flask_restful import Api, Resource
from werkzeug.security import safe_str_cmp

class User(object):
    def __init__(self, id, username, password):
        self.id = id
        self.username = username
        self.password = password

    def __str__(self):
        return "User(id='%s')" % self.id

users = [
    User(1, 'xyz', 'xyz'),
    User(2, 'user2', 'abcxyz'),
]

username_table = {u.username: u for u in users}
userid_table = {u.id: u for u in users}

def authenticate(username, password):
    user = username_table.get(username, None)
    if user and safe_str_cmp(user.password.encode('utf-8'), password.encode('utf-8')):
        return user

def identity(payload):
    user_id = payload['identity']
    return userid_table.get(user_id, None)

app = Flask(__name__)
app.debug = True
app.config['SECRET_KEY'] = 'super-secret'

jwt = JWT(app, authenticate, identity)

api = Api(app)

class HelloWorld(Resource):
    @jwt_required()
    def get(self, user_id):
        return {'hello': 'world'}

    @jwt_required()
    def put(self, user_id):
        user = None
        if user is None:
            return {"message": "User not found!"}, 404

api.add_resource(HelloWorld, '/<string:user_id>')


if __name__ == '__main__':
    app.run()

requirements.txt

aniso8601==1.3.0
click==6.7
Flask==0.12.2
Flask-JWT==0.3.2
Flask-RESTful==0.3.6
itsdangerous==0.24
Jinja2==2.9.6
MarkupSafe==1.0
PyJWT==1.4.2
python-dateutil==2.6.1
pytz==2017.2
six==1.11.0
Werkzeug==0.12.2

And then in POSTMAN all requests working whether JSON is sent or not

Without Body

With Body

It may have to do with some package version issue. I would suggest you run

pip install flask-jwt flask-restful --force --upgrade

To get the latest versions and see if that fixes the issue. If not then try running with debug=True in your app.run()

I really appreciate your support. I tried upgrading to latest version and added `debug=True`, I still get `No handlers could be found for logger "flask_jwt"` and I still get `Could not get any response` in Postman although server log is correct `127.0.0.1 - - [03/Nov/2017 22:18:09] "PUT /customer/2 HTTP/1.1" 404 -` — Mohamed_AbdAllah, Nov 03 '17 at 20:18
@Mohamed_AbdAllah, can't debug a issue without a reproducible source code. — Tarun Lalwani, Nov 04 '17 at 04:28

Flask-jwt error with Flask-restful if request contain JSON

1 Answers1