feat(auth): add /api/session router (setup, login, logout, me, change-password)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/web/api/session.ts

@@ -0,0 +1,150 @@
+import { Router } from "express";
+import type { Request, Response, NextFunction } from "express";
+import type { Logger } from "../../logger.js";
+import type { UserStore } from "../../data/users.js";
+import { UsernameTakenError } from "../../data/users.js";
+import type { SessionStore } from "../../data/sessions.js";
+import { SESSION_TTL_MS } from "../../data/sessions.js";
+import { SESSION_COOKIE_NAME, validateSessionFromHeaders } from "../auth/validateSession.js";
+
+const FAILED_LOGIN_DELAY_MS = 250;
+
+function setSessionCookie(res: Response, token: string): void {
+  res.cookie(SESSION_COOKIE_NAME, token, {
+    httpOnly: true,
+    sameSite: "lax",
+    secure: res.req.secure,
+    path: "/",
+    maxAge: SESSION_TTL_MS,
+  });
+}
+
+function clearSessionCookie(res: Response): void {
+  res.clearCookie(SESSION_COOKIE_NAME, { path: "/" });
+}
+
+function delay(ms: number): Promise<void> {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
+function isValidUsername(v: unknown): v is string {
+  return typeof v === "string" && /^[A-Za-z0-9_\-.]{3,32}$/.test(v);
+}
+
+function isValidPassword(v: unknown): v is string {
+  return typeof v === "string" && v.length >= 8 && v.length <= 200;
+}
+
+function parseTokenFromCookie(cookieHeader: string | undefined): string | null {
+  if (!cookieHeader) return null;
+  const match = cookieHeader
+    .split(";")
+    .map((p) => p.trim())
+    .find((p) => p.startsWith(`${SESSION_COOKIE_NAME}=`));
+  if (!match) return null;
+  return decodeURIComponent(match.slice(SESSION_COOKIE_NAME.length + 1));
+}
+
+export function createSessionRouter(
+  users: UserStore,
+  sessions: SessionStore,
+  logger: Logger
+): Router {
+  const router = Router();
+
+  const requireAuthInline = (req: Request, res: Response, next: NextFunction) => {
+    const result = validateSessionFromHeaders(req.headers.cookie, sessions);
+    if (!result) {
+      clearSessionCookie(res);
+      res.status(401).json({ error: "unauthenticated" });
+      return;
+    }
+    req.user = { id: result.userId, username: result.username };
+    next();
+  };
+
+  router.get("/needs-setup", (_req, res) => {
+    res.json({ needsSetup: users.countUsers() === 0 });
+  });
+
+  router.post("/setup", async (req, res) => {
+    const { username, password } = req.body ?? {};
+    if (users.countUsers() !== 0) {
+      res.status(409).json({ error: "already initialized" });
+      return;
+    }
+    if (!isValidUsername(username) || !isValidPassword(password)) {
+      res.status(400).json({ error: "invalid username or password" });
+      return;
+    }
+    try {
+      const user = await users.createUser(username, password);
+      const { token } = sessions.createSession(user.id);
+      setSessionCookie(res, token);
+      logger.info({ userId: user.id, username }, "First admin created");
+      res.json({ id: user.id, username: user.username });
+    } catch (err) {
+      if (err instanceof UsernameTakenError) {
+        res.status(409).json({ error: "already initialized" });
+        return;
+      }
+      logger.error({ err }, "setup failed");
+      res.status(500).json({ error: "internal" });
+    }
+  });
+
+  router.post("/login", async (req, res) => {
+    const { username, password } = req.body ?? {};
+    if (typeof username !== "string" || typeof password !== "string") {
+      res.status(400).json({ error: "invalid request" });
+      return;
+    }
+    const user = users.findByUsername(username);
+    const ok = user ? await users.verifyPassword(password, user.passwordHash) : false;
+    if (!user || !ok) {
+      await delay(FAILED_LOGIN_DELAY_MS);
+      res.status(401).json({ error: "invalid credentials" });
+      return;
+    }
+    const { token } = sessions.createSession(user.id);
+    setSessionCookie(res, token);
+    res.json({ id: user.id, username: user.username });
+  });
+
+  router.post("/logout", (req, res) => {
+    const token = parseTokenFromCookie(req.headers.cookie);
+    if (token) {
+      sessions.deleteSession(token);
+    }
+    clearSessionCookie(res);
+    res.status(204).end();
+  });
+
+  router.get("/me", requireAuthInline, (req, res) => {
+    res.json(req.user);
+  });
+
+  router.post("/change-password", requireAuthInline, async (req, res) => {
+    const { oldPassword, newPassword } = req.body ?? {};
+    if (typeof oldPassword !== "string") {
+      res.status(400).json({ error: "invalid request" });
+      return;
+    }
+    const u = users.findById(req.user!.id);
+    if (!u || !(await users.verifyPassword(oldPassword, u.passwordHash))) {
+      await delay(FAILED_LOGIN_DELAY_MS);
+      res.status(401).json({ error: "invalid credentials" });
+      return;
+    }
+    if (!isValidPassword(newPassword)) {
+      res.status(400).json({ error: "invalid request" });
+      return;
+    }
+    await users.changePassword(u.id, newPassword);
+    const currentToken = parseTokenFromCookie(req.headers.cookie);
+    sessions.deleteAllForUser(u.id, currentToken ?? undefined);
+    res.status(204).end();
+  });
+
+  return router;
+}