middleware.test.ts

import {NextRequest} from 'next/server';
import {afterEach, describe, expect, it, vi} from 'vitest';

// Helper to import the middleware module fresh with given env vars.
// isDeveloperDocs and redirectMap are evaluated at module load time,
// so we need a fresh import per env var scenario.
const ENV_KEYS = ['DEVELOPER_DOCS', 'NEXT_PUBLIC_DEVELOPER_DOCS'] as const;

async function importMiddleware(env: Record<string, string> = {}) {
  vi.resetModules();
  vi.unstubAllEnvs();

  // Save originals so we can restore after import
  const saved = new Map<string, string>();
  for (const key of ENV_KEYS) {
    if (key in process.env) {
      saved.set(key, process.env[key]!);
    }
    delete process.env[key];
  }

  for (const [key, value] of Object.entries(env)) {
    vi.stubEnv(key, value);
  }

  const mod = await import('./middleware');

  vi.unstubAllEnvs();

  // Restore any originals that were deleted
  for (const [key, value] of saved) {
    process.env[key] = value;
  }

  return mod;
}

function makeRequest(path: string): NextRequest {
  return new NextRequest(new URL(path, 'http://localhost:3000'));
}

function isRedirect(res: Response): boolean {
  return res.status === 301 || res.status === 302;
}

describe('middleware redirect set selection', () => {
  afterEach(() => {
    vi.unstubAllEnvs();
  });

  // "/" only exists in DEVELOPER_DOCS_REDIRECTS, so it's a good signal
  // for which redirect set is active without hardcoding destinations.

  describe('when DEVELOPER_DOCS is set (build-time inline via next.config.ts)', () => {
    it('activates developer docs redirect set', async () => {
      const {middleware} = await importMiddleware({DEVELOPER_DOCS: '1'});
      expect(isRedirect(middleware(makeRequest('/')))).toBe(true);
    });
  });

  describe('when NEXT_PUBLIC_DEVELOPER_DOCS is set (runtime fallback)', () => {
    it('activates developer docs redirect set', async () => {
      const {middleware} = await importMiddleware({NEXT_PUBLIC_DEVELOPER_DOCS: '1'});
      expect(isRedirect(middleware(makeRequest('/')))).toBe(true);
    });

    it('does not use user docs redirects', async () => {
      const {middleware} = await importMiddleware({NEXT_PUBLIC_DEVELOPER_DOCS: '1'});
      // user-docs-only path should not redirect in developer docs mode
      expect(isRedirect(middleware(makeRequest('/platforms/python/http_errors/')))).toBe(
        false
      );
    });
  });

  describe('when NEXT_PUBLIC_DEVELOPER_DOCS is not set (docs.sentry.io)', () => {
    it('activates user docs redirect set', async () => {
      const {middleware} = await importMiddleware({});
      // "/" should NOT redirect in user docs mode
      expect(isRedirect(middleware(makeRequest('/')))).toBe(false);
    });

    it('does not use developer docs redirects', async () => {
      const {middleware} = await importMiddleware({});
      // developer-docs-only path "/docs-components/" should not redirect
      expect(isRedirect(middleware(makeRequest('/docs-components/')))).toBe(false);
    });
  });

  describe('pass-through', () => {
    it('does not redirect unknown paths', async () => {
      const {middleware} = await importMiddleware({});
      expect(isRedirect(middleware(makeRequest('/not/a/real/path/')))).toBe(false);
    });

    it('does not redirect unknown paths in developer docs mode', async () => {
      const {middleware} = await importMiddleware({NEXT_PUBLIC_DEVELOPER_DOCS: '1'});
      expect(isRedirect(middleware(makeRequest('/not/a/real/path/')))).toBe(false);
    });
  });
});

describe('canonical Link header on .md responses', () => {
  afterEach(() => {
    vi.unstubAllEnvs();
  });

  it('adds Link rel=canonical pointing to the HTML page for a deep path', async () => {
    const {middleware} = await importMiddleware({});
    const res = middleware(makeRequest('/platforms/apple/cocoa.md'));
    expect(res.headers.get('Link')).toBe(
      '<https://docs.sentry.io/platforms/apple/cocoa/>; rel="canonical"'
    );
  });

  it('maps /index.md to the root canonical URL', async () => {
    const {middleware} = await importMiddleware({});
    const res = middleware(makeRequest('/index.md'));
    expect(res.headers.get('Link')).toBe('<https://docs.sentry.io/>; rel="canonical"');
  });

  it('handles top-level .md paths', async () => {
    const {middleware} = await importMiddleware({});
    const res = middleware(makeRequest('/platforms.md'));
    expect(res.headers.get('Link')).toBe(
      '<https://docs.sentry.io/platforms/>; rel="canonical"'
    );
  });

  it('uses develop.sentry.dev origin in developer docs mode', async () => {
    const {middleware} = await importMiddleware({NEXT_PUBLIC_DEVELOPER_DOCS: '1'});
    const res = middleware(makeRequest('/platforms/apple/cocoa.md'));
    expect(res.headers.get('Link')).toBe(
      '<https://develop.sentry.dev/platforms/apple/cocoa/>; rel="canonical"'
    );
  });

  it('does not add Link header for non-.md paths', async () => {
    const {middleware} = await importMiddleware({});
    const res = middleware(makeRequest('/platforms/apple/cocoa/'));
    expect(res.headers.get('Link')).toBeNull();
  });
});

describe('wantsMarkdownViaAccept: text/plain no longer triggers markdown', () => {
  it('does not serve markdown for Accept: application/json, text/plain, */*', async () => {
    const {middleware} = await importMiddleware({});
    const req = new NextRequest(new URL('/platforms/apple/cocoa/', 'http://localhost:3000'), {
      headers: {'Accept': 'application/json, text/plain, */*'},
    });
    const res = middleware(req);
    // Should not rewrite to .md — Next rewrite changes the URL; a plain next() keeps it
    expect(res.headers.get('x-middleware-rewrite')).toBeNull();
  });

  it('still serves markdown for explicit text/markdown Accept header', async () => {
    const {middleware} = await importMiddleware({});
    const req = new NextRequest(new URL('/platforms/apple/cocoa/', 'http://localhost:3000'), {
      headers: {'Accept': 'text/markdown'},
    });
    const res = middleware(req);
    // A rewrite to .md will set x-middleware-rewrite
    expect(res.headers.get('x-middleware-rewrite')).toContain('.md');
  });
});