Codespace asp.net core v7 authentication POST returns 404

[mikedice]

Question: How to forward POST request in codespace

Body

I have set up a repo with an asp.net core v7 project in it and added the code to use authentication for Microsoft Account (MSA). The auth flow, in a nutshell is GET request to the server which returns a redirect to login.microsoftonline.com which after user is authenticated does a POST request back to my app with all the stuff required to identify the authenticated user. In asp.net core I have full Info level logging turned on. This app is running in a codespace with port forwarding. This is what I see

• First leg GET request. I see full debug output in the code space and can see that asp.net has responded to the GET request as expected
• I type in my credentials
• From the browser I see the POST request issued back to my service with the codespace port forwarded URL
• Inside the codespace I see no debug tracing for the POST request.

From this I conclude the POST request never made it through the Codespace port forwarder and into the app running inside the container. In the container I right clicked on the forwarded port and changed visibility to public. Still same issue. No POST request being forwarded. This blocks development of apps that use this type of auth flow (oauth)

Any ideas on how to debug or fix would be appreciated.

[osortega]

Hello @mikedice 👋
In this case it sounds like you will need to change the Redirect URI on your AAD app configuration.
Otherwise, AAD will not be able to POST back to your callback endpoint.

The only issue with this is that the URL might change depending on the port you use for forwarding the app, unless you make it as standard on your app that it should be forwarded on a particular port.

The other option I see is to set up a device code authentication so that you don't have to worry about the callback at all.

You can find more information on setting up an AAD authentication provider here.

Hope this helps!

[mikedice]

No it is not exactly the case. There is something in the GitHub Copilot proxy (NGINX I think) that is blocking the request.

If my signin callback URL is /signin-oidc it gets blocked and my server running in the container will not see the POST request

I changed my signin callback URL from /signin-oidc to /myauth-complete and now it works!

[mikedice]

It might be better if the GITHUB Copilot proxy used a non-standard sign-in callback route so that people using copilot don't have to figure this out on their own. The sign in callback route my app was using was wizard generated by one of the dotnet core app templates.

[mikedice]

I got the hint from this article:
https://blog.martincostello.com/github-codespaces-gotchas-with-aspnetcore-oauth/

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