Email sign-in's codes are mailed over SMTP (pub.dev's mailer), through
whichever service the passwords name: emailSmtpHost, emailSmtpPort,
emailSmtpUser, emailSmtpPassword and emailFrom (EMAIL_SMTP_* and
EMAIL_FROM in deploy/.env, with EMAIL_SIGN_IN_PEPPER). TLS only:
STARTTLS, or TLS directly on 465. learn.halkyon.eu sends through Proton's
SMTP submission. Without a service, codes still go to the log in
development, and elsewhere there is no email sign-in.
The mail is plain text, in English or German: the code first and in the
subject, so it shows in the notification and the system can offer it,
the instance it signs in to, its 15 minutes, and that it can be ignored;
no links, no tracking, no HTML. A mail that couldn't be sent is a refusal
of its own (mailFailed): nothing of the request is kept, and the log
names the error's type only, as the service's answer may name the
address. A fake SMTP server on loopback drives the real mailer in the
tests: it delivers, and nothing goes to a server without TLS.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
People without GitHub can now keep an anonymous account, and sign in on
another device, with an email address and a code mailed to it each time;
no password. The instance keeps only HMAC-SHA256 of the address, keyed
with its emailSignInPepper (ADR 0010): from what someone types it finds
the person and tells whether an address is free, it mails only an address
someone has just typed, and it can't write to anybody otherwise or show
anybody their address. The device remembers the address it signed in
with, in the person's folder, to show it.
It works as GitHub does. A code for a new address makes it the signed-in
person's, who becomes identified and keeps everything. A code for another
person's address gives a switch token, which signs in as them without a
session; a device holding studysets asks first. Asking for a code answers
alike for every address. Codes are eight Crockford characters, valid 15
minutes and three tries (Serverpod's code challenges); three codes an
hour per address, ten per network. In development the code goes to the
server's log; elsewhere there is no email sign-in until a mail service
is set up (instance.info().emailSignIn).
Someone identified may add the other way in: the Profile tab lists how
they sign in and adds GitHub or an address. They are never switched to
another account: an address or GitHub account that is another's is said
to be so. Switching now deletes the account left behind only when it was
anonymous; it deleted any, which only anonymous people could reach so far.
The migration adds email_identity and email_code_request with their
indexes and foreign keys to Serverpod's challenges; nothing else changes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
