AWS Amplify/Cognito: Dynamically Selecting Auth Flow - amazon-web-services

I'd like to set up an authentication system in AWS Amplify with a Cognito User Pool that supports either the USER_SRP_AUTH or CUSTOM_AUTH, and have the app dynamically select between the two at the sign-in step.
The Amplify documentation for Switching Authentication Flows shows how you can do this by updating the global Amplify config, but is there any way to do this by just setting a single value (the authentication flow) instead of needing to store, update, and set the entire Amplify configuration each time?

Related

AWS Amplify Appsync change default authorization mode form API KEY to IAM

In my React app all users are enabled to use a feature that makes use of an API (GraphQL) to mutate data in DB. My React app is hosted and served using AWS Amplify and my API is on AWS Appsync. Previously I used an API KEY to authenticate my app to my API, however, now I would like to change authentication method from API KEY to IAM. I have changed the Default authorization mode in the AWS Appsync Console (see attached image) and done amplify push and amplify codegen, however when I test my app in both development and production environment I get status code 401 (sometimes 403) from my API whenever I try to call it, what am I missing?
I haven't added any additional configuration on the app side, not sure where and how to add the appropriate credentials.
Changing directly in the console will not reflect in other environments with amplify push also it's not recommended.
Try using amplify update api with AWS CLI,
and do amplify push, it will update the auth config.

Amazon cognito not giving refresh token provided by federated identity provider (Google login)

I am trying to add a Google login through Amazon Cognito, I have setup everything needed, I have also configured the attribute mapping from google to my pool attributes, I've mapped 'access_token' attribute to 'google_access_token' attribute and 'refresh_token' to 'google_refresh_token'. When sign in process starts, google prompts me for required permissions needed and redirects back to my app, and I can see on cognito dashboard that user is added with access token mapped in 'google_access_token' but no refresh token there. I double checked every configuration everything seems fine. I also tried mapping other attributes like 'token_type' and 'expires_in' those are getting mapped except the refresh token.
I found out that for generating refresh token from google, client need to pass 'access_type=offline' parameter in the GET parameters which Amazon Cognito DOESNOT send while starting OAUTH login with google, so google doesnt provide google refresh token. So in nutshell there is no way ( Atleast now ) to get refresh token from google and access google APIs "offline" if you are using Amazon cognito. Alternatively I used Auth0 which supports this and can send access_type parameter to google and can store refresh token.
If I may ask, have you seen this document?
Understanding Amazon Cognito user ool oauth 2.0 grants
To get to the point, this concern may be because of the OAuth Flow we have set in the Cognito User Pool. We need to use "Authorization Code Grant" as the OAuth flow. Implicit Grant doesn't generate refresh tokens, but Authorization Code Grant does.
If you're using Amplify framework in your project, this framework will do most of the heavy lifting for you. You just need to setup the User Pool's app client correctly and configure Amplify for that specific app client.
I hope this helps.

AWS Authentication

I am trying to authenticate users via AWS Cognito/IAM services from my webapp. I have implemented Facebook and LinkedIn login and I'm wondering how I could use AWS to implement username+password login via my UI. Is there a way for me to set it up so that all I have to do is drop in button for username+password login on my view and that will authenticate users and redirect back to my backend service (similar to Facebook/LinkedIn) and where I can put in an endpoint URL?
Do let me know If I need to be clearer.
Edit1: I have already tried using Developer Authenticated Workflow (enhanced workflow). I don't want to do the part where I create the User in my user pool by calling the AWS Cognito Identity API. I'd like AWS to do the user creation by itself. is this possible?
Edit2: Another alternative solution is to create a Lambda which does what I want. But this is similar to the code to do that (which is on my backend).
At the moment there is no complete solution for this. You have to either use newly introduced AWS Cognito User Pools or create your own one. I would also recommend to checkout the project https://github.com/danilop/LambdAuth which worth trying.
You can create AWS Cognito user pools and create the roles for authenticated and unauthenticated users and assign some policies for both roles. Once you have created the user pool you will necessary code to use in your web or mobile application. Refer How to setup Cognito user pools.

Confused on use/ need of cognito

So since parse is shutting down we are moving our website / mobile app that we've been developing to AWS. We are primarily going to use the following services:
SNS, SES, Dynamo, S3, Lambda.
Now I am still a bit confused on:
what cognito is used for? Do we really need cognito to authenticate users and use DynamoDB, S3, SNS ? Or can we just use specific APIs for each of these services and connect directly (using Js SDK)?
If we do have to use cognito how do we save local data i.e logged in user/ identity? is that what cognito sync is for or do we have to use cookies ?
In summary why do I need cognito when I can directly connect to DynamoDB using the JavaScript SDK?!
Thank you in Advance.
Amazon Cognito can be decomposed in two sub-services: Amazon Cognito Identity and Amazon Cognito Sync.
Think of the former as an authentication service and a credentials provider. The latter is just a service to store user data and keep it synchronized between multiple devices.
What is the purpose of Amazon Cognito Identity?
Suppose that you have a table in DynamoDB. Let's say that you have a web application that will store an item on that table.
You can create an user in IAM, embed the credential information on the web application, and then put the item on the table using the AWS SDK.
There are three things going on here:
The credentials are embedded in the application
The credentials do not expire.
Every user in your application has the same access rights on your table
This may be fine for some applications, but Amazon Cognito Identity offers a solution to these common problems.
Let me explain Cognito Identity's workflow:
An user registers an account on your application, sending all the information (username, password, other data...) to your server.
The server stores the user in some back-end database (it could be a DynamoDB table) and creates a new identity on the Cognito service. This identity is then mapped to this user.
The user can now login into your application. The user logins and sends username and password to your server. (This process could be done automatically after account registration)
The server checks the username and password against your back-end database. If everything is right, then the server makes a request to Amazon Cognito for a temporary access token.
The web application receives the token and makes a request to Amazon Cognito (using that access token) to get the user credentials. These credentials are basically a temporary IAM user that was created specifically for this user. It will have an expiration (usually an hour).
The web application uses these credentials to make operations on AWS, such as putting an item on a DynamoDB table, or calling a Lambda.
When the credentials expire, the user must re-login into the application. This might be done automatically or not, depending on your application's requirements.
On the Amazon Cognito dashboard, you can configure roles and policies for your "identities" (an user in Cognito). This way you can specify which services it can access. It even allows you to create access roles for your users (Admin users may be able to access some services that normal users should not).
I should also note that Amazon Cognito can be easily adapted to support Facebook / Google+ / Amazon accounts, which will be mapped to the same identity, so the user can login via multiple sources.
What is the purpose of Amazon Cognito Sync?
Consider it like a DynamoDB table where you store information for a specific user. These information is shared between multiple devices and is always synchronized. This means that when a web application updates an user value, then the mobile application will automatically reflect this change.
There is a limit on how much user data you can store (I don't remember now), so it's not something you would use to persist information (such as an user password), but rather a mean to share information.

sendMessage to SQS from Browser

I am building an SPA with Django REST as the backend. Right now I am using the standard Django authentication system and User models.
I would like the JS running on the SPA to be able to insert messages into an AWS SQS (i.e. sendMessage).
AWS has these doc on calling sendMessage from JS in the browser.
They also provide these docs on how to authenticate the user. My thought right now is to use Amazon Cognito. From the FAQ:
Q: What if I register and authenticate my own users?
Amazon Cognito can integrate with your existing identity system. With
a simple API call you can retrieve a Cognito ID for your end users
based on your own unique identifier for your users. Once you have
retrieved the Cognito ID and OpenID Token Cognito provides, you can
use the Cognito client SDK to access AWS resources and synchronize
user data.
Am I correct that for this to work, I would need to:
Create an IAM user for each user in my system. Or do I just need one IAM role?
When the user logins in my site (Django backend), I would have my backend then make "a simple API call [to] retrieve a Cognito ID"
Send that Cognito ID when the user loads the SPA.
User the Cognito ID from the JS running in the browser to call sendMessage to the SQS queue
Am I missing something here? Is there someway to remove the Django User backend and just user IAM Users so that I can avoid having to keep the two users lists in sync? I found this project but it does not seem to be maintained.
UPDATE:
It seems that there might be an alternative method of doing this where I don't use Cognito at all but rather expose an endpoint that can sign requests, "Query Request Authentication". This Heroku page talks a little about building a signing service.
Is this in fact an alternative option and if so what are the pro/cons of these approaches?
Amazon Cognito does not require you to register IAM users, just the 2 IAM roles. A slight modification to what you would need to do:
Create an Amazon Cognito Identity pool, configure with your developer provider.
Update the IAM roles associated with your pool to allow access to the services you want (for instance SQS).
From your Django backend, call GetOpenIdTokenForDeveloperIdentity to get the OpenId Connect token and identity Id for this user, return this to your JS application.
Configure your CognitoCredentials in the JS SDK. In the logins map, use the key cognito-identity.amazonaws.com and the value as the token returned from your Django backend.
Use the JS SDK to call SQS or any other services you wish from your application.
While using pre-signed URLs for SQS can work, using Cognito with the JS SDK will allow you to leverage other services supported by the SDK (DynamoDB, SNS, S3, etc).