Detect if PHP session exists

Question

Facebook now offer subscriptions to users so you can get realtime updates on changes. If my app receives an update, I plan to store it in the database. I would also like to detect if their session exists. If it does then I could update the data in there too. My session IDs are MD5(fb_id + secret) so I could easily edit their session. The question is how can I detect if the session exists.

Accepted Answer

If `$_SESSION` (or `$HTTP_SESSION_VARS` for PHP 4.0.6 or less) is used, use `isset()` to check a variable is registered in `$_SESSION`.

```
isset($_SESSION['varname'])
```

Detect if PHP session exists

Solution

Problem