How Can I Create a Persistent Cookie in PHP Without an Expiration Date?

Extended Cookie Expiration for Persistent Sessions

The requirement to set a cookie to never expire arises frequently when developing web applications that require persistent user sessions. However, the PHP documentation suggests setting an expiration date for cookies. While you can set a cookie to expire at the end of the session or in the future, you may wonder if there's a way to make a cookie last indefinitely.

Cookie Expiration Limitation

Unfortunately, all cookies have an expiration period as per the cookie specification. This expiration is not a PHP limitation but a fundamental property of cookies.

Approximating Never Expiration

To simulate a never-expiring cookie, you can set a distant future date as the expiration time. For instance, you could set a cookie to expire in ten years:

setcookie(
  "CookieName",
  "CookieValue",
  time() + (10 * 365 * 24 * 60 * 60)
);

This approach effectively extends the cookie's lifespan beyond the user's typical session or device usage timeframe.

32-Bit PHP Limitation

Note that for 32-bit PHP, setting an expiration date past 2038 can result in a wrap-around effect, effectively causing the cookie to expire immediately.

Browser Limitations

In 2023, web browsers have started to enforce a maximum expiration date for cookies. As of Chrome release M104, cookies can no longer have an expiration date more than 400 days in the future.

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