Your client code looks OK, mine has ClientId param in it but if your code is not raising an exception then it should be fine. Unless you had Generate client secret option checked when you created your app client.
If that is the case then you have to pass in SECRET_HASH in AuthParameters like the following:
import hmac
import hashlib
import base64
def get_secret_hash(email, client_id, client_secret):
"""
A keyed-hash message authentication code (HMAC) calculated using
the secret key of a user pool client and username plus the client
ID in the message.
"""
message = email + client_id
client_secret = str.encode(client_secret)
dig = hmac.new(client_secret, msg=message.encode('UTF-8'), digestmod=hashlib.sha256).digest()
return base64.b64encode(dig).decode()
client.admin_initiate_auth(
UserPoolId=COGNITO_USER_POOL_ID,
ClientId=CLIENT_ID,
AuthFlow='CUSTOM_AUTH',
AuthParameters={
'USERNAME': email,
'SECRET_HASH': get_secret_hash(email, CLIENT_ID, CLIENT_SECRET) # Omit if secret key option is disabled.
},
)
Next, double check the following:
Under App clients > * > Auth Flows Configuration, is ALLOW_CUSTOM_AUTH option enabled for your client?
Under App integration > App client settings > * > Enabled Identity Providers, is your user pool selected?
If you have Cognito setup correctly and your code still doesn't work then it is probably the lambda code. You probably know this but for password-less custom auth you need to use 3 lambda triggers: Define Auth Challenge, Create Auth Challenge, and Verify Auth Challenge.
Custom auth lambdas events are triggered in the following order:
- DefineAuthChallenge_Authentication:
- Technically, issueTokens can be set to True here to return tokens without going through the rest of the steps.
def lambda_handler(event, context):
if event['triggerSource'] == 'DefineAuthChallenge_Authentication':
event['response']['challengeName'] = 'CUSTOM_CHALLENGE'
event['response']['issueTokens'] = False
event['response']['failAuthentication'] = False
if event['request']['session']: # Needed for step 4.
# If all of the challenges are answered, issue tokens.
event['response']['issueTokens'] = all(
answered_challenge['challengeResult'] for answered_challenge in event['request']['session'])
return event
- CreateAuthChallenge_Authentication:
def lambda_handler(event, context):
if event['triggerSource'] == 'CreateAuthChallenge_Authentication':
if event['request']['challengeName'] == 'CUSTOM_CHALLENGE':
event['response']['privateChallengeParameters'] = {}
event['response']['privateChallengeParameters']['answer'] = 'YOUR CHALLENGE ANSWER HERE'
event['response']['challengeMetadata'] = 'AUTHENTICATE_AS_CHALLENGE'
return event
Then your client must respond to the challenge:
client.respond_to_auth_challenge(
ClientId=CLIENT_ID,
ChallengeName='CUSTOM_CHALLENGE',
Session=session,
ChallengeResponses={
'USERNAME': email,
'ANSWER': 'Extra Protection!',
'SECRET_HASH': get_secret_hash(email, CLIENT_ID, CLIENT_SECRET) # Omit if secret key option is disabled.
}
)
- VerifyAuthChallengeResponse_Authentication:
def lambda_handler(event, context):
if event['triggerSource'] == 'VerifyAuthChallengeResponse_Authentication':
if event['request']['challengeAnswer'] == event['request']['privateChallengeParameters']['answer']:
event['response']['answerCorrect'] = True
return event
- DefineAuthChallenge_Authentication:
- Set
event['response']['issueTokens'] to True to return tokens (code shown in step 1), or issue another challenge to keep repeating steps 1-3.
Finally, make sure that if case-insensitivity option is enabled for your user pool too. Also, I can't exactly recall if CUSTOM_AUTH flow worked if the user is in FORCE_CHANGE_PASSWORD status. If the user is in that state, then try settings a permanent password with the sdk to set the status to CONFIRMED.
