Passwordless logins

Mailbox challenges also work well for passwordless login flows.

Generate and email the challenge

backend/login.ts

import { Passlock, isChallengeRateLimitedError } from "@passlock/server";

const passlock = new Passlock({ ... });

// cpatured in a login form
const email = "...";

const user = await findUserByEmail(email);
if (!user) {
  throw new Error("Account not found");
}

const result = await passlock.createMailboxChallenge({
  email,
  userId: user.id,
  purpose: "login",
  // any pending "login" challenges for this userId will be nuked
  invalidateOthers: true,
});

if (result.success) {
  const { challengeId, secret, message } = result.value.challenge;

  // save this in the user's session or a secure HTTP only cookie
  await savePendingChallenge({
    purpose: "login"
    challengeId,
    secret,
  });

  await emailCodeToUser({ email, message });
} else if (isChallengeRateLimitedError(result.error)) {
  return showRateLimit(result.error.retryAfterSeconds);
} else {
  throw new Error(result.error.message);
}

Verify the code and create a session

backend/login.ts

import { Passlock } from "@passlock/server";

const passlock = new Passlock({... });

// fetch from the user's session or secure cookie
const pendingChallenge = await loadPendingChallenge({ purpose: "login" });

const result = await passlock.verifyMailboxChallenge({
  challengeId: pendingChallenge.challengeId,
  secret: pendingChallenge.secret,
  code: form.code, // the user submitted this
});

if (result.success) {
  const { challenge } = result.value;
  await createLoginSession(challenge.userId);
} else {
  return throw new Error(result.error.message);
}