I have 2 react native apps that are connected to a single aws backend. And I have deployed a post-confirmation lambda function so that I can save items (Users etc.) into the dynamo db storage. I want to know how do I adjust my lambda function so that If someone signup from the user side of my app it save an item in the user table of dynamo db and if someone signup from the driver side of the app it saves an item in the driver table of dynamo db. Can I use context param to check whether from which side of the app someone is signing up?
You can use clientMetaData to pass parameters to the PostConfirmation Lambda function.
await Auth.signUp({
username,
password,
clientMetadata: {
isDriver: false,
},
});
and in the PostConfirmation Lambda
const AWS = require("aws-sdk");
exports.handler = async (event, context, callback) => {
AWS.config.region = event.region;
// you can access like this
// event.request.clientMetadata.isDriver
context.succeed(event);
};
var normalAuth = async (username, password) => {
try{
var user = await Auth.signIn(username, password)
console.log(user)
if(user.challengeName === "NEW_PASSWORD_REQUIRED"){
console.log("assigning new password!")
user = await Auth.completeNewPassword(user, "password") // give the user a new password. this would NOT be included in any kind of production code, its only here as a work around
console.log(user)
} // work around. users created in the console are only given temporary passwords, and as such have no authorization
// setting a new password will fix this
console.log(await Auth.currentCredentials()) // THIS THROWS AN ERROR?!?!
setAuthState(false) // auth is no longer in progress
}
catch(error){
console.error(error)
}
}
I'm trying to grab the tokens from my Amplify user after authenticating but I'm receiving the error
No Cognito Identity pool provided for unauthenticated access
This is pretty strange because I'm not using an identity pool at all. My baseline assumption was that I shouldn't need to provide an identity pool ID at all in my amplify config.
config looks like this
var amplifyConfig = {
Auth: {
mandatorySignIn: false,
region: "us-east-1",
userPoolId: "mypoolid",
userPoolWebClientId: "myclientid"
}
}
The really weird part is that the tokens are actually there in user after I authenticate. It's only when I try and retrieve them this way specifically that an error is thrown.
Any idea what's going on here?
In my Android app, I want my users to be able to change their email addresses (that they use to connect to their accounts), without getting any verification code by email.
So far, I manage to change the email address, and thanks to a lambda, set email_verified to true automatically. But unfortunately, an email is still sent with a verification code...
Here is what I did in my Android app:
public void onClickChangeEmail(View view)
{
CognitoUserAttributes attributes = new CognitoUserAttributes();
attributes.getAttributes().put("email", "second#mail.com");
CognitoSettings
.getCognitoUserPool(MainActivity.this)
.getCurrentUser()
.updateAttributesInBackground(attributes, new UpdateAttributesHandler()
{
#Override
public void onSuccess(List<CognitoUserCodeDeliveryDetails> attributesVerificationList)
{
Log.i("tag", "Email updated!");
}
#Override
public void onFailure(Exception e)
{
e.printStackTrace();
}
});
}
And in my AWS console, I added a trigger in Cognito on Custom message, and here is my lambda function, which is triggered everytime a user updates his email:
const AWS = require('aws-sdk')
AWS.config.update({region: 'eu-central-1'});
exports.handler = (event, context, callback) => {
if (event.triggerSource === 'CustomMessage_UpdateUserAttribute')
{
const params = {
UserAttributes: [
{
Name: 'email_verified',
Value: 'true',
},
],
UserPoolId: event.userPoolId,
Username: event.userName,
};
var cognitoIdServiceProvider = new AWS.CognitoIdentityServiceProvider();
cognitoIdServiceProvider.adminUpdateUserAttributes(params, function(err, data) {
if (err) context.done(err, event); // an error occurred
else context.done(null, event); // successful response
});
}
else
{
context.done(null, event);
}
};
The only workaround I found is to throw an error instead of context.done(null, event);, but it doesn't look like a clean solution.
Is there a better and cleaner way to prevent Cognito from sending a verification email?
Thanks for your help.
I am calling the Cognito API in my Springboot Service and I am able to update a user's email without getting a verification code. In my adminUpdateUserAttributes() method, I am passing in:
Name: 'email_verified',
Value: 'true'
together with the email field that needs to be updated and it updates successfully without sending an email. Maybe the labda doesn't work correctly or they have fixed the bug since this is an old question.
The goal is to implement a social provider auth flow as described in User Pools App Integration and Federation.
One important thing that I want to satisfy, is to merge user pool accounts that have the same email address.
I am accomplishing that by calling adminLinkProviderForUser within the PreSignUp_ExternalProvider cognito lambda trigger.
So with this, everything works. The new social provided user is being registered and linked with the already existing Cognito (user+pass) user.
However, the authentication flow, from user's perspective doesn't complete. It fails at the last step where the callback uri (defined in cognito user pool) is being called:
error: invalid_request
error_description: Already found an entry for username Facebook_10155611263152353
But then, if the user retries the social auth flow, everything works, and would get session tokens that represent the original Cognito User Pool user (the one that already had that email).
Note that I'm testing the auth flow on an empty User Pool, zero user accounts.
For all the poor souls fighting with this issue still in 2020 the same way I did:
I have eventually fixed the issue by catching the "Already found an entry for username" in my client application and repeating the entire auth flow once more.
Luckily the error only gets fired on the initial external provider signup but not in the subsequent signins of the same user (cause it happens during signup trigger, duh).
I'm taking a wild guess, but here is what I think is happening:
In my case, the facebook provider was getting succesfully linked with
the pre-existing cognito email/password user. new Facebook userpool
entry linking to the email/password user was succesfully created.
Still, it seems
like cognito tried to register the fully isolated Facebook_id user
during the internal signup process (even though a link user entry with the same username was already created in the previous step). Since the "link user" with the
username Facebook_id was already existing, cognito threw an
"Already found an entry for username Facebook_id error" internal error.
This error has been repeatedly voiced over to the AWS developers since 2017 and there are even some responses of them working on it, but in 2020, it's still not fixed.
Yes, this is how it is currently setup. If you try to link users using PreSignUp trigger, the first time won't work. A better way to handle this(I think) would be to provide an option in your UI to link external accounts on sign-in. In the pre-signup trigger, search for a user with the same unique attribute (say email) and see if the sign up is from external provider. Then show a message such as email already exists. Login in & use this menu/option to link. Haven't tested this though.
To elaborate on #agent420's answer, this is what I am currently using (Typescript example).
When a social identity attempts to sign up and the email address already exists I catch this using the PreSignUp trigger and then return an error message to the user. Inside the app, on the user's profile page, there is an option to link an identity provider which calls the adminLinkProviderForUser API.
import {
Context,
CognitoUserPoolTriggerEvent,
CognitoUserPoolTriggerHandler,
} from 'aws-lambda';
import * as aws from 'aws-sdk';
import { noTryAsync } from 'no-try';
export const handle: CognitoUserPoolTriggerHandler = async (
event: CognitoUserPoolTriggerEvent,
context: Context,
callback: (err, event: CognitoUserPoolTriggerEvent) => void,
): Promise<any> => {
context.callbackWaitsForEmptyEventLoop = false;
const { email } = event.request.userAttributes;
// pre sign up with external provider
if (event.triggerSource === 'PreSignUp_ExternalProvider') {
// check if a user with the email address already exists
const sp = new aws.CognitoIdentityServiceProvider();
const { error } = await noTryAsync(() =>
sp
.adminGetUser({
UserPoolId: 'your-user-pool-id',
Username: email,
})
.promise(),
);
if (error && !(error instanceof aws.AWSError)) {
throw error;
} else if (error instanceof aws.AWSError && error.code !== 'UserNotFoundException') {
throw error;
}
}
callback(null, event);
};
I finally got this thing working in a non-weird way where users have to authorize twice or other things.
Process explained:
User tries to authenticate using an identity provider, for the first time => PreSignUp lambda kicks in and check if user exists via email
1a. If the user exists, it will throw an error, eg. CONFIRM_IDENTITY_LINK_token that I'm capturing on the client.
token is a base64 string with the username and identity id ("username:facebook_123456")
1b. If the username does not exist, I create a new user with a temporary password and throw an error FORCE_CHANGE_PASSWORD_token. Same token but I add the temporary password to this time.
In the client I have one callback route '/authorize' => this is the one you set up as a callback URL in Cognito, and 2 extra routes: '/confirm-password' and '/configure-password'.
In the /authorize route I'm capturing the errors and getting the attached tokens and redirect to the extra routes: 1a => /configure-password?token=token and 1b => /confirm-password?token=token
For "/confirm-password" I ask the user to confirm its current password in order to authorize linking with the provider, then use the token to log him in with the identity id as clientMetadata, eg "{"LINK_PROVIDER": "facebbok_12345678"}"
On login, I have a PostAuthentication lambda which checks for the "LINK_PROVIDER" in the clientMetadata, and links it to the user.
For "/configure-password" I parse the token and do a "shallow" login with the credentials from the token and identity id as client metadata (same as above) then prompt the user to configure a new password for his account.
I know it might seem a little bit restrictive but I find it better than to authorize twice.
Also, this does not create extra users for identities in the user pool.
Code examples:
PreSignUp lambda
export async function handler(event: PreSignUpTriggerEvent) {
try {
const { userPoolId, triggerSource, request, userName } = event
if (triggerSource === 'PreSignUp_ExternalProvider') {
// Check if user exists in cognito
let currentUser = await getUserByEmail(userPoolId, request.userAttributes.email)
if (currentUser) {
// User exists, thow error with identity id
const identity = Buffer.from(`${currentUser}:${userName}`).toString('base64')
throw new Error(`CONFIRM_USER_IDENTITY_${identity}`)
}
// Create new Cognito user with temp password
const tempPassword = generatePassword()
currentUser = await createNewUser(userPoolId, request.userAttributes, tempPassword)
// Throw error with token
const state = Buffer.from(`${currentUser}:${tempPassword}:${userName}`).toString('base64')
throw new Error(`FORCE_CHANGE_PASSWORD_${state}`)
}
return event
} catch (error) {
throw new Error(error)
}
}
PostAuthentication lambda
export async function handler(event: PostAuthenticationTriggerEvent) {
try {
const { userPoolId, request, userName } = event
if (request.clientMetadata?.LINK_IDENTITY) {
const identity = request.clientMetadata['LINK_IDENTITY']
// Link identity to user
await linkIdentityProvider(userPoolId, userName, identity)
}
return event
} catch (error) {
console.error(error)
throw new Error('Internal server error')
}
}
We faced the same issue and tried various hacks to get around it. As we started to use SignInWithApple, we couldn't handle it with the 'double turnaround' because Apple always wants the user to enter their email and password, not like Google, where the second time, everything works automatically. So the solution we ended up building was to store the Cognito/IdP ID (Google_1234, SignInWithApple_XXXX.XXX.XXX) in our database but still create a native Cognito user that isn't linked via Cognito.
The native user is created to make unlinking easier because first, we get rid of the data (IdP user-id) we store in our database and then the Cognito IdP user. The user can then proceed using the Native Cognito user. Then we have a middleware component in place that allows us to have JWT in the external IdP or Cognito native format and translates so we can use both versions. As long as the user uses an IdP/SSO, we reset the Native users' password to a very long random value and prevent resetting it, so they must use the IdP.
So whatever you are trying to do, prevent using the admin-link-provider-for-user command!
The same code in JavaScript getUser has been called instead of listUsers. It is also assumed that all users have their email id as their username.
const aws = require('aws-sdk');
exports.handler = async (event, context, callback) => {
console.log("event" + JSON.stringify(event));
const cognitoidentityserviceprovider = new aws.CognitoIdentityServiceProvider({apiVersion: '2016-04-18'});
const emailId = event.request.userAttributes.email
const userName = event.userName
const userPoolId = event.userPoolId
var params = {
UserPoolId: userPoolId,
Username: userName
};
var createUserParams = {
UserPoolId: userPoolId,
Username: emailId,
UserAttributes: [
{
Name: "email",
Value: emailId
},
],
TemporaryPassword: "xxxxxxxxx"
};
var googleUserNameSplitArr = userName.split("_");
var adminLinkUserParams = {
DestinationUser: {
ProviderAttributeName: 'UserName',
ProviderAttributeValue: emailId,
ProviderName: "Cognito"
},
SourceUser: {
ProviderAttributeName: "Cognito_Subject",
ProviderAttributeValue: googleUserNameSplitArr[1],
ProviderName: 'Google'
},
UserPoolId: userPoolId
};
var addUserToGroupParams = {
GroupName: "Student",
UserPoolId: userPoolId,
Username: emailId
};
if (userName.startsWith("Google_")) {
await cognitoidentityserviceprovider.adminGetUser(params, function (err, data) {
if (err) {
console.log("No user present")
console.log(err, err.stack);
cognitoidentityserviceprovider.adminCreateUser(createUserParams, function (err, data) {
if (err) console.log(err, err.stack);
else {
console.log("User Created ")
cognitoidentityserviceprovider.adminAddUserToGroup(addUserToGroupParams, function (err, data) {
if (err) console.log(err, err.stack);
else {
console.log("added user to group");
console.log(data);
}
});
cognitoidentityserviceprovider.adminLinkProviderForUser(adminLinkUserParams, function (err, data) {
if (err) console.log(err, err.stack);
else {
console.log("user linked");
console.log(data);
}
});
console.log(data);
}
});
} else {
console.log("user already present")
cognitoidentityserviceprovider.adminLinkProviderForUser(adminLinkUserParams, function (err, data) {
if (err) console.log(err, err.stack); // an error occurred
else {
console.log("userlinked since user already existed");
console.log(data);
}
});
console.log(data);
}
});
}
console.log("after the function custom");
callback(null, event);
};
This is a well know error. I handle it by retrying the request after this error and it will work. The error is because there is not way in the SDK to let it know to the pool that you already link the Federation Credentials to an user and it try to create a new user with those credentials
I wanted to have the feature of having a user seamlessly being able to login with one social provider (ex: Facebook) and then another one (Google).
I struggled with the retry process, especially with Google Login. At the signup process, if a user have several accounts, he will need to process twice the account selection.
What I ended up doing is just using Cognito for the client side code and token generation and have a lambda in the pre signup process mapping userIds with their email in a custom DB (Postgres or DynamoDB).
Then when a user query my API, based on their userId (whether it's a FacebookId or a cognito email userId, I am querying the DB to find the linked email and I am able to authenticate any users and their data like this.
Did this bug all of a sudden stop happening on 2/21/23? We didn't change anything but now this is no longer happening to users on their first time signing up. We also noticed that the UI for how Cognito is showing linked users is different - there is just 1 cognito account you're able to see in Cognito instead of multiple. You can still see the federated linked accounts in the identities property though
Question
I have a lambda function triggered when someone registers via federated identities that creates an entry in a dynamodb table.
I want the same function (or similar) to occur when a user registers (I was thinking post confirm) via an associated user pool.
Background (what I've attempted)
I've linked the federated identity to the user pool but the lambda linked to the Cognito trigger does not get called for user pools. I thought it may not support the same process (is this the case?) and tried adding a customised workflow trigger to the user pool for post confirm. I just get an error back (bad request 400) stating '{"__type":"NotAuthorizedException","message":"User cannot confirm."}' although the user is showing as confirmed in Cognito.
I've looked at the documentation but I don't see many clear examples. The best I found was one emailing on post confirm which I modified to contain a basic dynamo call as follows:
var doc = require('dynamodb-doc');
exports.handler = function(event, context) {
console.log(event);
if (event.request.userAttributes.email) {
var db = new doc.DynamoDB();
var tableName = 'Users'
var user = {
'id' : event.identityId,
'name' : event.datasetRecords.name.newValue,
'email' : event.datasetRecords.email.newValue,
};
var params = {
'TableName' : tableName,
'Item' : user
};
console.log('Inserting user', params);
db.putItem(params, function(err, data) {
console.log(err, data);
if (err) {
console.log('User insert failure', err);
context.done(err);
} else {
console.log('User insert success', data);
context.done(null, event);
}
});
} else {
// Nothing to do, the user's email ID is unknown
context.done(null, event);
}
};
I've looked at similar questions and nearest I found was this
previous question
although it does not include a working code snippet. I've tried a few variations but no luck!
As stated there I have also seen callbacks used in other examples so it would be good to clear up what the preferred and working code should look like!
I would also like to know if it should return data within the context.done in a particular format as I saw some set responses like the following:
"response": {
}
Many thanks!
Calling ConfirmSignUp on already confirmed user throws the error "User cannot confirm". As a result of that post confirmation lambda function is not called. Though this error could be more descriptive.
Have you looked at this example from the docs already?
http://docs.aws.amazon.com/cognito/latest/developerguide/cognito-user-identity-pools-working-with-aws-lambda-triggers.html#aws-lambda-triggers-post-confirmation-example