feat(auth): add SessionStore with rolling renewal and at-rest token hashing

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

src/data/sessions.test.ts

@@ -0,0 +1,103 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from "vitest";
+import { createHash } from "node:crypto";
+import { createDatabase, type BotDatabase } from "./database.js";
+import { createUserStore, type UserStore } from "./users.js";
+import { createSessionStore, type SessionStore, SESSION_TTL_MS, SESSION_TOUCH_INTERVAL_MS } from "./sessions.js";
+
+function sha256(token: string) {
+  return createHash("sha256").update(token).digest("hex");
+}
+
+describe("SessionStore", () => {
+  let botDb: BotDatabase;
+  let users: UserStore;
+  let sessions: SessionStore;
+  let userId: string;
+
+  beforeEach(async () => {
+    botDb = createDatabase(":memory:");
+    users = createUserStore(botDb.db);
+    sessions = createSessionStore(botDb.db);
+    const u = await users.createUser("alice", "pw");
+    userId = u.id;
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+    botDb.close();
+  });
+
+  it("createSession returns a raw token whose sha256 matches the DB row id", () => {
+    const { token } = sessions.createSession(userId);
+    const row = botDb.db.prepare("SELECT id FROM sessions").get() as { id: string };
+    expect(row.id).toBe(sha256(token));
+    expect(row.id).not.toBe(token);
+  });
+
+  it("validateAndTouch returns the user for a fresh token", () => {
+    const { token } = sessions.createSession(userId);
+    const result = sessions.validateAndTouch(token);
+    expect(result).not.toBeNull();
+    expect(result!.userId).toBe(userId);
+    expect(result!.username).toBe("alice");
+  });
+
+  it("validateAndTouch returns null and deletes the row for an expired session", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    const { token } = sessions.createSession(userId);
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z").getTime() + SESSION_TTL_MS + 1000);
+    expect(sessions.validateAndTouch(token)).toBeNull();
+    const remaining = (botDb.db.prepare("SELECT COUNT(*) AS n FROM sessions").get() as { n: number }).n;
+    expect(remaining).toBe(0);
+  });
+
+  it("validateAndTouch does not write the DB if called again within the touch interval", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    const { token } = sessions.createSession(userId);
+    const before = botDb.db.prepare("SELECT lastSeenAt FROM sessions").get() as { lastSeenAt: number };
+    vi.advanceTimersByTime(SESSION_TOUCH_INTERVAL_MS - 1000);
+    sessions.validateAndTouch(token);
+    const after = botDb.db.prepare("SELECT lastSeenAt FROM sessions").get() as { lastSeenAt: number };
+    expect(after.lastSeenAt).toBe(before.lastSeenAt);
+  });
+
+  it("validateAndTouch writes lastSeenAt and extends expiresAt past the touch interval", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    const { token, expiresAt: initialExpiry } = sessions.createSession(userId);
+    vi.advanceTimersByTime(SESSION_TOUCH_INTERVAL_MS + 1000);
+    sessions.validateAndTouch(token);
+    const row = botDb.db.prepare("SELECT lastSeenAt, expiresAt FROM sessions").get() as { lastSeenAt: number; expiresAt: number };
+    expect(row.lastSeenAt).toBe(Date.now());
+    expect(row.expiresAt).toBeGreaterThan(initialExpiry);
+  });
+
+  it("deleteSession removes the row", () => {
+    const { token } = sessions.createSession(userId);
+    sessions.deleteSession(token);
+    const remaining = (botDb.db.prepare("SELECT COUNT(*) AS n FROM sessions").get() as { n: number }).n;
+    expect(remaining).toBe(0);
+    expect(sessions.validateAndTouch(token)).toBeNull();
+  });
+
+  it("deleteAllForUser keeps the exceptToken session", () => {
+    const a = sessions.createSession(userId);
+    const b = sessions.createSession(userId);
+    sessions.deleteAllForUser(userId, a.token);
+    expect(sessions.validateAndTouch(a.token)).not.toBeNull();
+    expect(sessions.validateAndTouch(b.token)).toBeNull();
+  });
+
+  it("cleanupExpired removes only expired rows", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z"));
+    sessions.createSession(userId); // expires later
+    vi.setSystemTime(new Date("2026-01-01T00:00:00Z").getTime() + SESSION_TTL_MS + 1000);
+    sessions.createSession(userId); // fresh
+    sessions.cleanupExpired();
+    const remaining = (botDb.db.prepare("SELECT COUNT(*) AS n FROM sessions").get() as { n: number }).n;
+    expect(remaining).toBe(1);
+  });
+});