Google登录令牌使用疑问：每次调用认证还是自定义JWT延长有效期？

Great question! Let's break this down based on your current setup and the trade-offs between the two approaches you're considering:

Option 1: Validate Google's ID Token on Every Request #

This is what you're doing right now, and it has clear pros and cons:

Pros

• No custom token management: Google handles all the heavy lifting—validating the token's signature, expiration, audience, and even checking if the user's Google account is still active.
• Immediate security feedback: If the user revokes access to your app or their Google account gets suspended, your next request validation will fail immediately, cutting off access right away.
• Simpler implementation: You don't need to build logic for generating, signing, or refreshing custom tokens. Just use Google's official libraries to validate the token each time.

Cons

• Performance overhead: Every request requires a round-trip to Google's validation API (like https://oauth2.googleapis.com/tokeninfo or using their client-side validation libraries). This adds latency, which can be noticeable in high-traffic apps.
• Third-party dependency: If Google's validation service goes down temporarily, your app's auth flow will break until it's restored.
• Poor user experience: A 1-hour token means users will get logged out frequently unless you implement silent token refresh (using a refresh token to fetch a new ID token without prompting the user).

Option 2: Generate a Custom JWT After Google Auth #

Switching to your own JWT gives you more control, but comes with extra responsibilities:

Pros

• Better performance: Validating a JWT only requires local signature verification (using your app's secret/key), no external API calls. This keeps your request latency low.
• Flexible expiration: You can set longer JWT lifetimes (e.g., 1 day or 7 days) and pair it with a refresh token to let users stay logged in without re-authenticating constantly.
• Provider agnosticism: If you ever want to add other login methods (like Facebook or email/password), you won't have to rework your entire auth flow—just map those users to your custom JWT system.

Cons

• Increased security overhead: You're now responsible for managing JWT signing keys (rotating them regularly), handling refresh token storage/expiry, and implementing token revocation if needed (like a blacklist for invalidated tokens).
• Delayed account status updates: If a user revokes Google access or their account is suspended, your app won't know until the custom JWT expires—unless you add periodic checks against Google's API for active users.

Recommended Hybrid Approach #

For most apps, combining both strategies gives you the best balance of security, performance, and user experience:

1. Initial auth: When a user logs in with Google, validate their ID token with Google's API to confirm their identity.
2. Issue custom tokens: Generate a short-lived custom JWT (e.g., 15-60 minutes) and a longer-lived refresh token (e.g., 7 days), storing both in secure, HttpOnly, Secure, SameSite cookies.
3. Request validation: For every incoming request, validate the custom JWT locally. This is fast and avoids external API calls.
4. Token refresh: When the JWT expires, use the refresh token to hit your backend. Your backend can either:
   • Trust the refresh token (if you've stored it securely and track its validity), or
   • Do a quick check against Google's API to confirm the user's account is still active, then issue a new JWT.
5. Re-authentication: If the refresh token expires, redirect the user back to Google login for re-authentication.

Key Security Notes #

• No matter which approach you choose, always set HttpOnly, Secure, and SameSite=Strict/Lax on your auth cookies to prevent XSS and CSRF attacks.
• If using custom JWTs, prefer asymmetric signing algorithms like RS256 over HS256—this way, you can keep your private key secure and only expose the public key for validation.

内容的提问来源于stack exchange，提问作者user3712353