parking_solution/wiki/entities/local-jwt-auth.md

type, tags, sources, updated

type	tags	sources	updated
entity	parking stack auth offline-first	parking-system-architecture	2026-06-15

Local JWT Auth

Authentication and authorization, kept fully local — a direct consequence of offline-first (an air-gapped park cannot reach an external identity provider; see logto-zitadel-oidc for the rejected alternative). (See parking-system-architecture §2.)

• @fastify/jwt signs tokens with a local secret (symmetric HMAC). The server refuses to start without a strong JWT_SECRET (≥32 chars, no placeholder) — there is deliberately no insecure default.
• Session lifetime: valid until explicit logout — no time expiry (decision 2026-06-15, built). Booth reality breaks any fixed clock: relief arrives late, fails to show, or one operator is forced to work two shifts in a row — a token that expired mid-duty would strand an active operator. So the login persists until logout; a shift is a separate, explicit boundary, not tied to token lifetime. (Superseded the earlier "8h expiry, bound to a shift" assumption.) The JWT carries no exp; the cookie has a long fixed maxAge (30 days) so a browser restart doesn't log out an active operator, and logout clears it.
• A users table in sqlite holds bcrypt password hashes plus a role column. The first admin is seeded via pnpm --filter @parking/server seed-admin (no bootstrap endpoint).
• Authorization = a simple preHandler role guard per route: admin / operator / cashier / readonly. No Casbin or full RBAC engine needed at this scale.

Cookie session (browser auth)

The SPA never sees the JWT. Login (POST /api/auth/login) verifies bcrypt and sets two cookies:

• parking_token — the JWT, HttpOnly + SameSite=Strict (+ Secure when NODE_ENV=production). JS can't read it; @fastify/jwt reads it from the cookie, not the Authorization header.
• parking_csrf — a random token, readable by JS. The JWT also carries a matching csrf claim. On every mutation the SPA echoes the cookie in the X-CSRF-Token header; the guard requires header == cookie == the signed claim (double-submit CSRF). Safe reads are exempt.

Routes: login, logout (clears cookies), me (bootstraps SPA session on load). The dev react-vite-spa proxy and the prod nginx reverse proxy keep the SPA and API same-origin, so the cookies work without CORS. (This replaced an earlier dev-only SETUP_AUTH_BYPASS shim, now removed.)

Open decision: moving from the symmetric secret to an asymmetric key (RS256/EdDSA) so verifying hosts hold only a public key — open-questions #7. Relevant before any multi-host/multi-lane deployment.

Part of the technology-stack. License: MIT.