Renewing Expired Azure Mobile Services Token

Question

I'm setting up an HTML5 and JavaScript web application to consume Azure Mobile Services tables using the JavaScript client library. I've managed to get authentication setup successfully with the MicrosoftAccount identity provider. On load, my application checks if the user is already logged in, or if we have a token and username stored locally. If true, I hide the login button, and display the logout button, and proceed to load application data.

My problem is that when a token that is stored locally expires, my application still thinks the user is logged in. Therefore when I request table data, I get a 401 Unauthorized HTTP response.

Is there a graceful pattern to renew an expired token without burdening the user with relogging in every time their token expires?

Answer 1

You will need to log the user in every time, unfortunately. The token must have a lifetime associated with it. On some client platforms, you can get much longer lifetimes via single-sign flows, but these are generally not available for HTML. The common pattern is to, upon receiving the 401, retrigger your login code. Here is a blog post showing the approach for the Mobile Services Managed SDK. The same concepts should apply for JS.