PHP Session Variables -> Accessing another unique identifier - php

Question

I have a problem right now where, when a user logs in, their user object is stored in a session variable as to be quicker than making a database call each time. The problem I am having is if something updates on their end (like the number of points they have), I have no way to modify that session variable, I can only update their row in the table.
Is there any way for php to access that session variable given it's unique identifier instead of reading from their cookie? Or would it be better to check some flag in the database, and if the flag is set, update all the information?

Answer 1

You need to read it from a centralized storage (contrary to sessions). If you could, you should avoid the database calls. Use cache and update the cache on insert:
user 1 checks cache for user 2's score
it's non-existing, so the call is forwarded to db
the score is still empty/0 so an entry in the cache is written like this: key: "goals-2" (unique identifier which is easy to figure out), value: "0"
user 2 scores a goal
the score for user-2 is calculated by checking the cache (which is empty) and then checking the db (which is empty/0): 0 is current score
the new score is 0 + 1 = 1
the new score is inserted to database (for persistence), the cache with the key "goals-2" is saved with the key "goals-2" and the value "1"
then we're done, let's try the loop again:
user 1 checks cache for user 2's score, finds "1"
user 1 checks cache again for user 2's score, finds "1"
We're saving really many database calls here.
Some possible engines for caching are:
APC
memcache
If you're on shared hosting, or unable to get PHP compiled with a good engine for caching, writing to files could do the job.

Answer 2

What I suggest is to create custom object which will hold data for example 5 minutes and than it will be reloaded. Just create object which will load your data from session, if loaded object is older than five minutes just reload data.
Load object
Check variable in object if (time()) its older than 5 min (or any custom time) reload data
If data reloaded update variable in object to new time and save it to session
I think this can resolve your problem
class MySession
{
public $Duration = 0;
public $Loaded = 0;
public static function Load()
{
$obj = null;
if(isset($_SESSION["my_session"]))
{
$obj = deserialize($_SESSION["my_session"]);
if((time()-$obj->Loaded)>$Duaration)
$obj = self::LoadObject();
}
else { $obj = self::LoadObject(); }
$obj->Save();
return $obj;
}
public function Save()
{
$_SESSION["my_session"] = serialize($this);
}
public static function LoadObject()
{
$obj = new MySession();
$obj->Loaded = time();
//logic for updating data
return $obj;
}
}