Generic error followed by HTTP 404 when signing with OpenID for the first time

Question

Recently I tried to log onto Biology SE for the first time. I clicked "log in", clicked the "MyOpenID" icon, entered the credentials on MyOpenID, then I was presented with "you have account on other sites" page and clicked "confirm and create".

Normally I would get logged in, but this time some generic error occurred and I got to https://biology.stackexchange.com/error?aspxerrorpath=/users/openidconfirm

I wanted to repro the problem and so edited the URL and tried to open https://biology.stackexchange.com/users/openidconfirm - I saw a HTTP 404 page with me signed in at the top of the page.

Not that I care much about an accidential error, but why would opening https://biology.stackexchange.com/users/openidconfirm result in HTTP 404 instead of redirecting me to the main page? I mean the page is to "confirm the OpenID" and I've already have it confirmed, so it's reasonable to just ignore the attempt and pretend nothing happened instead of showing me a 404 error page.

Could you please replace the HTTP 404 with forwarding in this case?

Answer 1

why would opening https://biology.stackexchange.com/users/openidconfirm result in HTTP 404 instead of redirecting me to the main page?

I mean the page is to "confirm the OpenID" and I've already have it confirmed, so it's reasonable to just ignore the attempt

The reason for the 404 is not the fact that you already were logged in. If that were so, you'd certainly have a point.

The reason is that this page is only meant to be requested via a POST request. Since typing the URL into the address bar by hand causes a GET request, you received a 404 (and yeah, I know the really correct response would be a 405).