I have implemented JWT for user login in my app (before Spotify Auth), like so:
Flask
@auth_blueprint.route('/auth/login', methods=['POST'])
def login_user():
# get post data
post_data = request.get_json()
response_object = {
'status': 'fail',
'message': 'Invalid payload.'
}
if not post_data:
return jsonify(response_object), 400
email = post_data.get('email')
password = post_data.get('password')
try:
# fetch the user data
user = User.query.filter_by(email=email).first()
if user and bcrypt.check_password_hash(user.password, password):
auth_token = user.encode_auth_token(user.id)
if auth_token:
response_object['status'] = 'success'
response_object['message'] = 'Successfully logged in.'
response_object['auth_token'] = auth_token.decode()
return jsonify(response_object), 200
else:
response_object['message'] = 'User does not exist.'
return jsonify(response_object), 404
except Exception:
response_object['message'] = 'Try again.'
return jsonify(response_object), 500
These are the methods of my SQLAlchemy User(db.Model)
def encode_auth_token(self, user_id):
"""Generates the auth token"""
try:
payload = {
'exp': datetime.datetime.utcnow() + datetime.timedelta(
days=current_app.config.get('TOKEN_EXPIRATION_DAYS'),
seconds=current_app.config.get('TOKEN_EXPIRATION_SECONDS')
),
'iat': datetime.datetime.utcnow(),
'sub': user_id
}
return jwt.encode(
payload,
current_app.config.get('SECRET_KEY'),
algorithm='HS256'
)
except Exception as e:
return e
@staticmethod
def decode_auth_token(auth_token):
"""
Decodes the auth token - :param auth_token: - :return: integer|string
"""
try:
payload = jwt.decode(
auth_token, current_app.config.get('SECRET_KEY'))
return payload['sub']
except jwt.ExpiredSignatureError:
return 'Signature expired. Please log in again.'
except jwt.InvalidTokenError:
return 'Invalid token. Please log in again.'
React
App.jsx
loginUser(token) {
window.localStorage.setItem('authToken', token);
this.setState({ isAuthenticated: true });
this.getUsers();
this.createMessage('Welcome', 'success');
};
(...)
<Route exact path='/login' render={() => (
<Form
isAuthenticated={this.state.isAuthenticated}
loginUser={this.loginUser}
/>
)} />
and
Form.jsx
handleUserFormSubmit(event) {
event.preventDefault();
const data = {
email: this.state.formData.email,
password: this.state.formData.password
};
const url = `${process.env.REACT_APP_WEB_SERVICE_URL}/auth/${formType.toLowerCase()}`;
axios.post(url, data)
.then((res) => {
this.props.loginUser(res.data.auth_token);
})
Third Party Authorization + Second App Authentication
Now I'd like to add a second layer of authentication and handle tokens after Spotify callback, like so:
@spotify_auth_bp.route("/callback", methods=['GET', 'POST'])
def spotify_callback():
# Auth Step 4: Requests refresh and access tokens
SPOTIFY_TOKEN_URL = "https://accounts.spotify.com/api/token"
CLIENT_ID = os.environ.get('SPOTIPY_CLIENT_ID')
CLIENT_SECRET = os.environ.get('SPOTIPY_CLIENT_SECRET')
REDIRECT_URI = os.environ.get('SPOTIPY_REDIRECT_URI')
auth_token = request.args['code']
code_payload = {
"grant_type": "authorization_code",
"code": auth_token,
"redirect_uri": REDIRECT_URI,
'client_id': CLIENT_ID,
'client_secret': CLIENT_SECRET,
}
post_request = requests.post(SPOTIFY_TOKEN_URL, data=code_payload)
# Auth Step 5: Tokens are Returned to Application
response_data = json.loads(post_request.text)
access_token = response_data["access_token"]
refresh_token = response_data["refresh_token"]
token_type = response_data["token_type"]
expires_in = response_data["expires_in"]
# At this point, there is to generate a custom token for the frontend
# Either a self-contained signed JWT or a random token?
# In case the token is not a JWT, it should be stored in the session (in case of a stateful API)
# or in the database (in case of a stateless API)
# In case of a JWT, the authenticity can be tested by the backend with the signature so it doesn't need to be stored at all?
res = make_response(redirect('http://localhost/about', code=302))
return res
Note: this a possible endpoint for getting new Spotify tokens:
@spotify_auth_bp.route("/refresh_token", methods=['GET', 'POST'])
def refresh_token():
SPOTIFY_TOKEN_URL = "https://accounts.spotify.com/api/token"
CLIENT_ID = os.environ.get('SPOTIPY_CLIENT_ID')
CLIENT_SECRET = os.environ.get('SPOTIPY_CLIENT_SECRET')
code_payload = {
"grant_type": "refresh_token",
"refresh_token": refresh_token,
}
encode = 'application/x-www-form-urlencoded'
auth = base64.b64encode("{}:{}".format(CLIENT_ID, CLIENT_SECRET).encode())
headers = {"Content-Type" : encode, "Authorization" : "Basic {}".format(auth)}
post_request = requests.post(SPOTIFY_TOKEN_URL, data=code_payload, headers=headers)
response_data = json.loads(post_request.text)
access_token = response_data["access_token"]
refresh_token = response_data["refresh_token"]
token_type = response_data["token_type"]
expires_in = response_data["expires_in"]
return access_token
What is the best way of handling my tokens after Spotify callback?
Considering that, once user is logged with the app, he will also be logged with Spotify non-stop, having to refresh Spotify's access token every 60 minutes:
Is Authorization Code a server-to-server flow only to protect secret app credentials, and then it is safe to have tokens at frontend?
Should I keep both Access token and refresh tokens stored at frontend, and have a Stateless JWT?
Should I keep only temporary access token and keep refresh tokens at database, having a Stateful JWT?
Should I opt for a Session, persisted only server-side, instead?
What is the safest way of handling my sensitive data here? And, considering the code above, how so?
