Oauth2 Implicit Flow with single-page-app refreshing access tokens

Question

I am using Thinktecture AuthorizationServer (AS) and it is working great.

I would like to write a native javascript single page app which can call a WebAPI directly, how

Answer 1

I understand that your problem is that the user will experience an interruption when the access token has expired, by a redirection to the login page of the authorization server. But I don't think you can and should get around this, at least, when using the implicit grant.

As I'm sure you already know, the implicit grant should be used by consumers that can NOT keep their credentials secret. Because of this, the access token that is issued by an authorization server should have a limited ttl. For instance google invalidates their access token in 3600 sec. Of course you can increase the ttl, but it should never become a long lived token.

Also something to note is that in my opinion the user interruption is very minimal, i.e if implemented correctly, the user will only have to authenticate once with the authorization server. After doing that (for example the first time when also authorizing the application access to whatever resources the user controls) a session will be established (either cookie- or token based) and when the access token of the consumer (web app using implicit grant) expires, the user will be notified that the token has expired and re authentication with the authorization server is required. But because a session already has been established, the user will be immediately redirected back to the web app.

If however this is not what you want, you should, in my opinion, consider using the authorization code grant, instead of doing complicated stuff with iframes. In that case you need a server side web application because then you can keep your credentials secret and use refresh tokens.