Check if Flask-HTTPAuth is authenticated inside view

Question

I'm using Flask-HTTPAuth for authentication. I want to display different data from a view depending on if the request was authenticated or not. Decorating the view with auth.login_required only shows it to authenticated users. How can I test if the request was authenticated with Flask-HTTPAuth?

auth = HTTPBasicAuth()

@app.route("/clothesInfo")
@auth.login_required
def show_info():
    return jsonify(blah blah blah)

I don't know if you can do this with flask-httpauth as you need a object passed to your template that contains the information if the user is authenticated. I know you definitely can do this with [Flask-Login](https://flask-login.readthedocs.io/en/latest/), see here http://stackoverflow.com/questions/18361151/using-flask-login-session-with-jinja2-templates — MrLeeh, Dec 14 '16 at 21:13

score 6 · Accepted Answer · answered Dec 15 '16 at 07:47

What you want is actually very easy to implement. In your verify_password callback, you will get username and password set to '' when the user does not provide credentials. You can still return True from that function, and that will allow the anonymous user to access the endpoint.

The following example demonstrates this technique:

auth = HTTPBasicAuth()

@auth.verify_password
def verify_password(username, password):
    if username == '' or password == '':
        # anonymous user, we still let them in
        g.current_user = None
        return True
    g.current_user = my_verify_function(username, password)
    return g.current_user is not None

@app.route("/clothesInfo")
@auth.login_required
def show_info():
    if g.current_user:
        # prepare data for authenticated users here
        pass
    else:
        # prepare data for anonymous users here
        pass
    return jsonify(data)

This answer is now outdated. Use `optional` parameter. See [my answer](https://stackoverflow.com/a/67606903/4653485). — Jérôme, May 19 '21 at 16:08

davidism · Answer 2 · 2018-08-16T02:51:30.607

You can decorate a function that returns None with login_required. Calling it while not authenticated will return an error response, calling it while authenticated will return None.

# a dummy callable to execute the login_required logic
login_required_dummy_view = auth.login_required(lambda: None)

def is_authenticated():
    try:
        # default implementation returns a string error
        return login_required_dummy_view() is None
    except HTTPException:
        # in case auth_error_callback raises a real error
        return False

@app.route('/info')
def info():
    if is_authenticated():
        # logged in view

    else:
        # basic view

See also Default login_required rather than adding decorator everywhere.

score 1 · Answer 3 · answered May 19 '21 at 16:07

Things are simpler since April 2020.

Flask-HTTPAuth 4.0.0 added optional argument to login required to do exactly this.

From the docs:

An optional optional argument can be set to True to allow the route to execute also when authentication is not included with the request, in which case auth.current_user() will be set to None. Example:
@app.route('/private')
@auth.login_required(optional=True)
def private_page():
    user = auth.current_user()
    return "Hello {}!".format(user.name if user is not None else 'anonymous')

Check if Flask-HTTPAuth is authenticated inside view

3 Answers3