What technology does Whatsapp Web utilize to sync a QR Code with a mobile device, or is that they pretty much rolled their own proprietary solution?
..?
wait, do you mean log in with qr or something
yea the login
it's pretty much an authentication code / attestation, many chinese sites do this
tencent games all do qr login
because people have to sign in via cybercafe computers that are unsafe/keylogged
it is straightforward to implement?
you scan the qr random token on your phone, enter u/p on your phone (in the app where the token is also attached/read), and they 'approve' that qr random token for login
are there libraries etc out there for programmers?
think of it as basically clicking a oauth button
except more state is handled by the server
not sure if there are libraries, i rarely if ever see this auth flow outside of asia
tl;dr afaik is session: asdfjkl (in QR; actually some maximally long crypto-random token) / app: scans qr and provides either existing token or a login window on a device you own; when you log in you basically tell it "tie this session to asdfjkl instead of creating a new one"
so in the browser afterward you just reload and your same cookie is already 'active'
right
i feel like there's probably not much of a library thing for this, but it should just be the same as a login form except tracking active but not used yet tokens in redis or something
and when they're consumed just dump it in your sessions db table or whatever