share VS github-auth3

I'll tack on mine as well, which you can self-host: https://github.com/schollz/share

Also there is a cute alias you can do to easily 'share' files:

alias share='f() { curl --progress-bar --upload-file "$1" https://share.schollz.com | tee /dev/null; echo };f'

This is incompatible with using curl as your client, but one “hacker-friendly way to do auth” is to use Github’s public SSH keys API.

You can stand up an (SCP/SFTP-subprotocol-only) SSH server, and then configure it to call[1] a check on GitHub’s API to map the user’s SSH key to a GitHub username.

From there, you can do whatever you like to continue the auth process: let any GitHub user in; only let GitHub users in from a specific GitHub org; keep an LDAP directory of GitHub usernames such that you can attach metadata to them like “is banned” or “has used up their upload credits for the day” or “is on plan tier X”; etc.

Then, set up automatic local user instantiation per remote user; populate /etc/skel with just the right set of limited files to allow the user to upload into one “spool” directory; and then have an inotify-like daemon that watches for files to be closed in that directory and handles them from there (e.g. uploading them to an S3 bucket, etc.)

[1] As it happens, I wrote an OpenSSHD plugin for exactly this: https://github.com/tsutsu/github-auth3