PHP: Store last viewed items in session array - php

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

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 2

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 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;
}