e-tib.com/tests/contact-antispam.test.ts

import { describe, it, expect, beforeEach } from 'vitest';
import { checkContactSubmission, resetRateLimiter } from '@/lib/antispam/contact-guard';
import { parseClientIp } from '@/lib/antispam/client-ip';
import { createFormToken } from '@/lib/antispam/form-token';

process.env.FORM_TOKEN_SECRET = 'test-secret';

const NOW = 1_000_000_000_000;
const TOKEN_SECRET = 'test-secret';

const validInput = () => ({
  honeypot: '',
  formToken: createFormToken(NOW - 10_000, TOKEN_SECRET),
  now: NOW,
  ip: '1.2.3.4',
  email: 'customer@example.com',
  message: 'I would like a quote for 50 cables.',
});

describe('client IP extraction from X-Forwarded-For', () => {
  it('uses the last hop appended by our own proxy, not the client-controlled first hop', () => {
    expect(parseClientIp('203.0.113.7, 198.51.100.2')).toBe('198.51.100.2');
  });

  it('handles a single hop', () => {
    expect(parseClientIp('203.0.113.7')).toBe('203.0.113.7');
  });

  it('returns null for missing or empty headers', () => {
    expect(parseClientIp(null)).toBeNull();
    expect(parseClientIp('')).toBeNull();
    expect(parseClientIp('  ')).toBeNull();
  });
});

describe('contact form anti-spam guard', () => {
  beforeEach(() => resetRateLimiter());

  it('allows a legitimate submission', () => {
    const result = checkContactSubmission(validInput());
    expect(result.allowed).toBe(true);
  });

  it('blocks submissions where the honeypot field is filled', () => {
    const result = checkContactSubmission({ ...validInput(), honeypot: 'http://spam.example' });
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('honeypot');
  });

  it('blocks submissions without a form token (direct POST without loading the form)', () => {
    const result = checkContactSubmission({ ...validInput(), formToken: null });
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('invalid_token');
  });

  it('blocks submissions with a forged form token', () => {
    const result = checkContactSubmission({ ...validInput(), formToken: '1234567890.forged' });
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('invalid_token');
  });

  it('blocks submissions sent faster than a human could fill the form', () => {
    const freshToken = createFormToken(NOW - 1_000, TOKEN_SECRET);
    const result = checkContactSubmission({ ...validInput(), formToken: freshToken });
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('too_fast');
  });

  it('blocks submissions with a stale token (page loaded more than a day ago)', () => {
    const staleToken = createFormToken(NOW - 25 * 60 * 60 * 1000, TOKEN_SECRET);
    const result = checkContactSubmission({ ...validInput(), formToken: staleToken });
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('expired_token');
  });

  it('blocks submissions with an invalid email address', () => {
    const result = checkContactSubmission({ ...validInput(), email: 'not-an-email' });
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('invalid_email');
  });

  it('blocks messages containing more than 5 links (typical SEO spam)', () => {
    const spammy = Array.from({ length: 6 }, (_, i) => `https://spam${i}.example`).join(' ');
    const result = checkContactSubmission({ ...validInput(), message: spammy });
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('too_many_links');
  });

  it('rate-limits an IP after 3 submissions within 10 minutes', () => {
    for (let i = 0; i < 3; i++) {
      expect(checkContactSubmission(validInput()).allowed).toBe(true);
    }
    const result = checkContactSubmission(validInput());
    expect(result.allowed).toBe(false);
    expect(result.reason).toBe('rate_limited');
  });

  it('does not rate-limit different IPs independently', () => {
    for (let i = 0; i < 3; i++) {
      checkContactSubmission(validInput());
    }
    const result = checkContactSubmission({ ...validInput(), ip: '5.6.7.8' });
    expect(result.allowed).toBe(true);
  });
});