MIDAS SSO example with OIDC using only JavaScript

An example of website serving static files using only JavaScript on python with SimpleHTTPServer, midas-sso and Auth0. For live demo, visit https://midas-isg.github.io/example-midas-sso-js-oidc/.

Hook up to midass-sso

This example shows how to hook up to midass-sso for the logged in user. After user signs up to midas-sso via MIDAS Accounts, the user will automatically get ISG_USER role. The example also demonstrates how to fetch user information from Auth0 and put into local storage for further useage.

The below is the original information from auth0-samples/oidc-sso-sample.

OIDC Single Sign-on Sample

Prerequisites

1. Go to https://manage.auth0.com/#/clients and create a single-page application client with OIDC Conformant mode enabled
2. Add http://localhost:3000 and http://localhost:3000/callback.html as allowed callback URLs
3. Enter your Auth0 domain and client ID in the auth0-variables.js file.

Running the sample

To start the sample, start a web server in the root of this repository at port 3000, or just run:

make

and then browse to http://localhost:3000.

How this sample works

We are checking two things in local storage to detect if a user is logged in or not:

• accessToken: the Auth0 access token to access our desired API, which in this case is /userinfo
• expirationDate: the expiration date of this token, calculated using the expires_in response parameter after a successful authentication

If there is no valid access token present in local storage, the user is not logged in to our application, but they might have logged in via SSO to another application. We can detect if this is the case by calling the renewAuth method of auth0.js, which will attempt to silently authenticate the user inside an iframe.

Silent authentication works in the same way as regular authentication (i.e. redirects the user to /authorize), but with some differences:

• A prompt=none parameter is added to the redirect to /authorize. This causes Auth0 to return an error in case the user is not logged in via SSO instead of displaying a login page.
• The redirect happens inside an iframe to preserve our application's state.
• The callback URL of this request is set to callback.html, which is a dedicated page to handle the silent authentication callback. This avoids loading your entire application again inside an iframe.

Two things can happen after a silent authentication request:

• The user did not have an active SSO session, so Auth0 calls back with an error (error=login_required)
• The user did have an active SSO session, so Auth0 calls back with an access token (access_token=...&expires_in=...)

In any case, the response from Auth0 is sent from the iframe back to the main page by using postMessage, which allows the main page to take action based on the outcome. In this sample we are immediately redirecting the user to the login page by using the authorize method of auth0.js if silent authentication failed, or storing the token and its expiration date in local storage if it succeeded.