PHP: Store last viewed items in session array

Question

I have a simple function that do this: 1) User view some image and image_id is stored in session array 2) Then user can see the last 10 viewed images

Currently my function is this:

function lastSeen($image_id){
    if(!isset($_SESSION['lastSeen'])){
        $_SESSION['lastSeen'] = array($image_id);
    }else{
        $tmpSession = array_unique($_SESSION['lastSeen']);
        if(count($tmpSession) > 9){
            $tmpSession = array_slice($tmpSession,1);
        }
        $tmpSession[] = $image_id;
        $_SESSION['lastSeen'] = array_unique($tmpSession);
    }
    return true;
}

This function works but the problem is that, if a user view one image more than one time, then in session are saved only 9 items. Can anybody help me solve this problem? Maybe the whole function needs to be rewrite it...

Answer 1

If you wouldn't mind that the order of images doesn't change, when the user views one image twice, then I would go with this simple solution. Just add line like this:

if (in_array($image_id, $tmpSession)) return true;

So your function would look like this:

function lastSeen($image_id){
    if(!isset($_SESSION['lastSeen'])){
        $_SESSION['lastSeen'] = array($image_id);
    } elseif (in_array($image_id, $_SESSION['lastSeen'])) {
       return true;
    } else {
        $tmpSession = array_unique($_SESSION['lastSeen']);
        if(count($tmpSession) > 9){
            $tmpSession = array_slice($tmpSession,1);
        }
        $tmpSession[] = $image_id;
        $_SESSION['lastSeen'] = array_unique($tmpSession);
    }
    return true;
}

Answer 2

You probably want to remove extraneous entries as the very last thing, and also only if it's more than 10 entries:

else {
   $tmpSession = $_SESSION['lastSeen'];
   $tmpSession[] = $image_id;  
   $tmpSession = array_unique($tmpSession);

   if(count($tmpSession) > 10){
       $tmpSession = array_slice($tmpSession,1);
   }
   $_SESSION['lastSeen'] = $tmpSession;
}

Answer 3

Another implementation of your function could be:

function lastSeen($image_id){
     if(!isset($_SESSION['lastSeen']) || !is_array($_SESSION['lastSeen'])){
          $_SESSION['lastSeen'] = array();
     }

     if(!in_array($image_id, $_SESSION['lastSeen']){
          array_push($_SESSION['lastSeen'], $image_id);
     }

     if(sizeof($_SESSION['lastSeen']) > 10){
          array_shift($_SESSION['lastSeen']);
     }
}

Answer 4

If you want a function that stores the last visited image as the last item in the array, then just replace:

$tmpSession = array_slice($tmpSession,1);

with the following line:

if (in_array($image_id,$tmpSession))
    array_splice($tmpSession, array_search($image_id, $tmpSession), 1);
else
    $tmpSession = array_slice($tmpSession, 1);

The result function would look like:

function lastSeen($image_id) {
if (!isset($_SESSION['lastSeen'])) {
    $_SESSION['lastSeen'] = array($image_id);
} else {
    $tmpSession = array_unique($_SESSION['lastSeen']);
    if (count($tmpSession) > 9){
        if (in_array($image_id,$tmpSession))
            array_splice($tmpSession, array_search($image_id, $tmpSession), 1);
        else
            $tmpSession = array_slice($tmpSession, 1);
    }
    $tmpSession[] = $image_id;
    $_SESSION['lastSeen'] = array_unique($tmpSession);
}
return true;

}