Why Does a 1-Week Token Lifespan in Rails 7 Devise Token Auth Trigger 401 Unauthorized?

Below is an explanation and some pointers on what might be happening:

What’s Likely Occurring

Devise‑token‑auth is set up with a default token lifespan of 2 weeks. When you reduce the lifespan to 1 week, the token validation appears to begin rejecting the token almost immediately. This behavior is not caused by your session controller or the model (which remain standard) but by how the gem compares the token’s “expiration” time.

Shortening the lifespan means that time-related comparisons (for example, the computed expiration based on when the token was issued versus what the configuration expects) can end up failing very quickly when the request for token validation is made. In effect, the newly issued token may already be determined to be expired by the time the client sends the subsequent validate token request.

What to Check

• Server Time and Time Zones:
  Make sure that the server’s clock and time-zone configuration are consistent and that there are no discrepancies between when the token is created and validated.

• Token Header Values:
  Devise‑token‑auth uses headers that include information about token timing. Confirm that the client is properly storing and sending back these headers after sign in.

• Token Expiry Calculations:
  Bear in mind that a “shorter” token lifespan means that any small delay between issuance and validation (or minor clock differences) can cause the token to be seen as expired.

Options for Moving Forward

1. Use the Default or a Longer Lifespan:
   Since a token lifespan of 3 weeks (or the default 2 weeks) works without problems, you might want to stick with those values if a secure refresh strategy isn’t in place to counteract timing issues.

2. Adjust Your Client/Server Strategy:
   If you must use a 1‑week lifespan, you might have to adjust how token expiration is handled. This could mean ensuring that the client immediately uses the new token and that any clock drift is minimized. In some cases, a custom override in the token validation logic (or a patch if one is available) may be required to support shorter lifespans.

3. Review Upstream Issues and Updates:
   There have been reports that lower lifespans when using devise‑token‑auth can encounter validation issues. Verify whether there is an update or workaround provided by the library’s maintainers that addresses a minimum token lifespan requirement.

Conclusion

There isn’t anything obviously “missing” from your code. Rather, when you lower the token_lifespan to 1 week, the timing between token creation and its validation ends up causing the gem to reject a token that it views as expired. You’ll either need to keep a longer lifespan (like 2 weeks or more) or adjust your token handling (or update the gem if an update supports lower lifespans) to accommodate a 1‑week lifespan.

Hopefully, the above pointers help you determine which route works best for your application’s security and usability needs!