Account Kit returning previous number and account kit ID when a new number is verified

Question

I am testing Account Kit (Basic Web version - phone number verification) on a Django (Python) based web app. One thing I try is logging with multiple accounts on localhost, and trying to link a different number to each one successively. If a number has already successfully attached to a previous account, I show an "already taken" error prompt. Standard stuff.

I've been noticing that I sporadically get the "already taken" error prompt on unused numbers as well. Investigating deeper, I found that although I had input and verified (via SMS) a new number, the account kit ID and mobile number returned to me was the previous pair.

I can't tell why this is happening. Can someone help me in debugging this? In case it matters, my authorization flow uses the app secret.

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Following are some relevant snippets. First, the Account Kit Manager class I've written:

from myproj.account_kit_settings import FAID, AKAS

class AccountKitManager(object):
    obj = None

    def __init__(self, app_id, app_secret):
        self.app_secret = app_secret
        self.app_access_token = 'AA|{0}|{1}'.format(app_id, app_secret)

    def get_user_cred(self, auth_code):
        if not self.obj:
            self.set_user_cred(auth_code)
        return self.obj

    def set_user_cred(self, auth_code, url=None):
        if not url:
            url = 'https://graph.accountkit.com/v1.2/access_token?grant_type=authorization_code&code={0}&access_token={1}&appsecret_proof={2}'.\
            format(auth_code,self.app_access_token,self.get_appsecret_proof(self.app_access_token))
        data = self.retrieve_data(url)
        data = self.evaluate_data(data)
        string_obj = self.retrieve_user_cred(data["access_token"])
        self.obj = self.evaluate_data(string_obj)

    def retrieve_user_cred(self, user_access_token, url=None):
        if not url:
            url = 'https://graph.accountkit.com/v1.2/me/?access_token={0}&appsecret_proof={1}'.\
            format(user_access_token,self.get_appsecret_proof(user_access_token))
        return self.retrieve_data(url)

    def retrieve_data(self, url):
        return requests.get(url).text

    def evaluate_data(self, data):
        return ast.literal_eval(data)

    def get_appsecret_proof(self, access_token):
        h = hmac.new(self.app_secret.encode('utf-8'),msg=access_token.encode('utf-8'),digestmod=hashlib.sha256)
        return h.hexdigest()

Next, here's how I use it:

mobile_data = AccountKitManager(FAID, AKAS)

def account_kit_handshake(csrf, state, status, auth_code):
    if csrf == state and status=='PARTIALLY_AUTHENTICATED':
        user_data = mobile_data.get_user_cred(auth_code)
        if FAID == user_data["application"]["id"]:
            return user_data["id"], user_data["phone"]
        else:
            # app id mismatch
            return None, None
    else:
        # csrf mismatch, or could not authenticate
        return None, None

def get_requirements(request):
    status = request.GET.get('status', None)
    auth_code = request.GET.get('code', None)
    state = request.GET.get('state', None)
    return account_kit_handshake(request.session["csrf"], state, status, auth_code)


def verify_consumer_number(request,*args,**kwargs):
    AK_ID, MN_data = get_requirements(request)
    request.session.pop("csrf",None)
    if AK_ID and MN_data:
        if someone_elses_number(MN_data['national_number'], request.user.id):
            return render(request,"used_number.html",{})
        else:
            save_consumer_credentials.delay(AK_ID, MN_data, request.user.id)
            return redirect("classified_listing")
    else:
        return render(request,"unverified_number.html",{})

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UPDATE: Seems the user access token isn't always being returned. This could be a problem with variable scope.

Answer 1

The problem emanated from the scope of the AccountKitManager class instance. It was being set globally (i.e. see mobile_data variable in my code). Making this variable local solved the problem.