Google OAuth does not work when Gitea is configured on a sub-path via NGINX

[luronumen]

Gitea Version

v1.26.4

What happened?

The current Nginx with a sub-path configuration is not sufficient to allow Gitea to perform authentication via Google OAuth.

Bug: Gitea is redirecting to /login/oauth/ instead of /gitea/login/oauth/

Workaround:
Added the following NGINX configuration:

        location ~ ^/login/oauth/ {
            rewrite ^/login/oauth/(.*)$ /gitea/login/oauth/$1 permanent;
        }

How are you running Gitea?

Nginx with a sub-path

[wxiaoguang]

Usually it's not recommended to put Gitea in a sub-path, it's not widely used and may have some issues in rare cases.

So, you can try to figure out whether /login/oauth must be on the root path:

1. if the standard (e.g. RFC) requires so, then it isn't Gitea's problem, you can only "bypass" it by your rewrite.
2. if no such requirement, you can try to figure out why the /login/oauth path doesn't have the sub-path when the callback happens
   • if it is your configuration bug, fix your configuration
   • if it is something missing in Gitea's code, point it out and/or propose a fix.