Making WPF Application (with Node Backend) Work With ADFS?

Question

One of our clients requested that we integrate our system with ADFS (Active Directory Federation Services) while another requested that we integrate with Okta. They want the experience to go something like this: the end users opens up the Windows app (on their domain joined computer) and is able to use it right away with implicit authentication from one of those identity providers. No extra clicking or registration. I am willing to create multiple copies of the application integrated into these different identity providers if necessary.

Our current setup uses Node/Express as a backend (hosted on amazon web services) and all traffic is sent through this API. Our client interface is a wpf Windows application. This seems to be a less common setup. Currently, the user must sign up with an email and password, and must log in using that same email and password to start using the application.

There are 3 parts to this question that I'm super confused about (I'm an intern with limited knowledge, so please explain like I'm 5 if possible). On the other hand, I believe I have a solid understanding of how Single Sign On conceptually works (with us being the service provider and ADFS/Okta being the identity provider). Even if you can answer parts of these questions, I would be super grateful!

1. What (if anything) do I have to do to our API backend? I'm assuming everything just needs to be done through the windows client right? But then I saw a passport saml package but I'm unsure if I need it to complete this task.

2. What do I have to do to our frontend? I've tried one of auth0's sample windows application but it seems like everything is still going through a login screen. At least for any social media connection. We'd like to ideally do this without a login screen and hopefully without proprietary software like Auth0 (since we manage our own user database already). We just want something so that at startup of our wpf application, the application queries for user's information (through ADFS or Okta) and then all behind the scenes, the user is logged in automatically. Any pointers here?

3. What I do have to do on the 'main' active directory Windows server side (this would be on a client's enterprise network)? I've seen hints of setting up callback urls, certificates, metadata, and something, but I'm unsure of what all of that is. Lots of questions just reference that but don't explain what or why it's needed?

Lastly, I apologize if any of the questions are vague, I have tried to do research, but it just seems like all the pieces are either too advanced or just don't apply to my setup. Thank you for your time!

Answer 1

ADFS etc. rely on federation protocols like WS-Fed and SAML 2.0 and so the IDP behavior is determined by the protocol.

There is no browser based functionality to just log you in.

You will always be taken to an IDP login screen. Once you have authenticated, other applications on the same IDP won't require authentication. They can seamlessly log you in based on cookies.

You can't query for user info. until you know who the user is.

On the ADFS side, you can manually configure a RP (your app).