The easiest way to present users a GUI that includes identity federation is to use Cognito Hosted UI. Cognito Hosted UI automatically adds “Continue With XXX” button based on the backend configuration.
You can test the Hosted UI by clicking on the link given by Amplify CLI at the end of the
amplify push command from previous section. For example, my link is:
The Hosted UI now shows the “Login With Facebook” button.
If you try to authenticate using Facebook using the above URI from a browser, you will be directed to Facebook’s page and be able to enter your email address and password. However the process will not terminate completly as the
redirect_uri in the URL is an iOS only URI that we gave for our app (
landmarks://) The final redirection will only work in our mobile app.
There is no code change to make this happen in the iOS app, as it using the Cognito hosted web UI too.
Build and launch the application to verify everything is working as expected. Click the build icon or press ⌘R.
If you are still authenticated, click Sign Out and click the user badge to sign in again. You should see the Amazon Cognito hosted UI. Click Continue With Facebook, follow the Facebook login process, including accepting Amplify iOS Workshop app to access your profile data and, eventually, you should see the Landmark list.
At this stage, no code change is required if you decide to add other identity providers to your backend configuration. The Hosted UI will automatically propose “Login with XXX” buttons based on the providers configured on the backend. All the interactions between the identity provider and Cognito happen on the backend, no client code is involved.
By choosing Continue with Facebook, you actually created a second identity in your backend. As seen from Amazon Cognito, the user you created earlier and the Facebook federated user are two different identities. You can connect to Amazon Cognito console, click on the user pool name (
amplifyiosworkshopxxxxx), select User and Groups on the left menu to verify two identities have been created: