get_jwt_identity() returning None in Flask-JWT-Extended

Question

I'm using Flask-JWT-Extended to protect my Flask API. After the Login, in the protected route (add-user), I call get_jwt_identity(), but it's returning None, so I'm not able to get the identity.

@flask_app.route('/<api_version>/login', methods=['POST'])
def login(api_version):
    print(f'login', request.form)
    response = None
    try:
        username = request.form['username']
        password = request.form['password']

        if not username:
            return jsonify({"msg": "Missing username parameter"}), 400
        if not password:
            return jsonify({"msg": "Missing password parameter"}), 400

        user = User.get_with_password(username, password)

        if (not user):
            e1 = Unauthorized(
                'Invalid username or password.  Please try again.')
            e1.status = 401
            raise e1

        """ flask_login.login_user(user, remember=True) """
        access_token = create_access_token(identity=username)
        response = json.dumps({"token": access_token}, cls=CustomJSONEncoder)
    except Exception as e:
        errMsg = f'Error Logging in user {username if username else ""}: {e}'
        status = e.status if hasattr(e, 'status') else 500
        print(f'{errMsg}')
        traceback.print_exc()
        return Response(
            json.dumps({"message": errMsg, "status": status, "stack": traceback.format_exc() }), status=status, mimetype='application/json')


    resp = Response(response, status=200, mimetype='application/json')
    return resp

@flask_app.route('/<api_version>/add-user', methods=['POST'])
@jwt_required
def add_user(api_version):
    print(f'add-user', request)
    response = None
    username = None
    password = None
    allow_admin = None
    try:
        data = request.get_json()
        print(f'add-user data', data)

        if 'username' in data:
            username = data['username']
        else:
            return jsonify({"msg": "Missing username parameter"}), 400
        if 'password' in data:
            password = data['password']
        else:
            return jsonify({"msg": "Missing password parameter"}), 400
        if 'allow_admin' in data:
            allow_admin = data['allow_admin']

        """ user = User.get_with_password(username, password)"""
        user = get_jwt_identity()
        print('user',user)

        if (not user):
            e1 = Unauthorized(
                'Invalid username or password.  Please try again.')
            e1.status = 401
            raise e1

        response = json.dumps({"user": user}, cls=CustomJSONEncoder)
    except Exception as e:
        errMsg = f'Error Adding User {username}: {e}'
        status = e.status if hasattr(e, 'status') else 500
        print(f'{errMsg}')
        traceback.print_exc()
        return Response(
            json.dumps({"message": errMsg, "status": status, "stack": traceback.format_exc() }), status=status, mimetype='application/json')


    resp = Response(response, status=200, mimetype='application/json')
    return resp

User.py

class User():
    @classmethod
    def get_with_password(cls, username, password):
        print(f'User get_with_password {username} with password')
        user_db = account.get_account(username)
        print(f'User returned from DB: {user_db}')

        user = User()
        if not user_db or not len(user_db) or (not 'password' in user_db):
            return None
        user.username = username
        user.id = username

        if bcrypt.check_password_hash(user_db['password'], password):

            user.role = user_db['role']
            #user.is_authenticated = True
            print(
                f'loginUser returning {vars(user)} ')
            return user
        return None

Answer 1

I've got the same issue and got it resolved by the following steps

Step1: Check if you have wrapped your app (flask_app) like the following.

from flask_jwt_extended import JWTManager
jwt = JWTManager(flask_app)
   

Step2: Check if you have JWT_BLACKLIST_ENABLED in your app or not.

If JWT_BLACKLIST_ENABLED = False or JWT_BLACKLIST_ENABLED not present in your app, add the following method above where ever you have used create_token_method() (in your case it is login method).

@jwt.user_claims_loader
def add_claims_to_access_token(identity):
    return {
        'identity': identity
    }

If JWT_BLACKLIST_ENABLED = True then add the following also above your login method.

@jwt.token_in_blacklist_loader
def check_if_token_in_blacklist(decrypted_token):
    jti = decrypted_token['jti']
    return jti in blacklist

Answer 2

I also faced same issue, in my case i forgot to add @jwt_required

@jwt_required
def get(self):
    uid = get_jwt_identity()
    print("self.uid",uid)

in your code @jwt_required is there, check may be token has expired