Set & GET PHP Session value using JavaScript in WordPress - php

Question

I am developing a plugin in which I get data from API, and then the user has an option to add this data to the cart and purchase the product. Everything works perfectly, except once we reload the page, the user cart value gets lost. How can I solve this?
I think one solution is, If we add the cart object to the session, it will be easy to use that session value to get the cart object. For this, I added the below function
my_file.js
function savecartObj(cartObj) {
$.post(
'cartObj.php',
{
cartobj : cartObj
},
function success(data) {
console.log(data);
}
);
}
and in my cartObj.php
<?php
/** Set up WordPress environment, just in case */
$path = preg_replace('/wp-content(?!.*wp-content).*/','',__DIR__);
require_once($path.'wp-load.php');
session_id() || session_start();
nocache_headers();
$_SESSION['ajjx'] = $_POST;
$value = '';
if (array_key_exists('ajjx', $_SESSION)) {
if (array_key_exists('cartobj', $_SESSION['ajjx']) {
$value = $_SESSION['ajjx']['cartobj'];
}
}
Header('Content-Type: application/json;charset=utf8');
die(json_encode(array(
'result' => $_SESSION['ajjx']['cart_obj'],
)));
Now I can see that $_SESSION['ajjx']['cart_obj'] is set and in console.log(data); I can see the session value. How can i use this value from $_SESSION['ajjx']['cartobj'] as cartobj in my_file.js
What I need is will create one file named get_session.php and in
that file, I will call the value of $_SESSION['ajjx']['cart_obj'] .
And then once my plugin is loaded I will call the value in
get_session.php & need to take the obj from the file and then add that value to add to cart function in the my_file.js. In that way, page reload doesn't
affect my cart.
Update
For getting the value I write the following function in my my_file.js
function get_cartObj(){
$.post(
'get_cartObj.php',
function success(data) {
console.log(data);
}
);
}
and in get_cartObj.php
<?php
/** Set up WordPress environment, just in case */
$path = preg_replace('/wp-content(?!.*wp-content).*/','',__DIR__);
require_once($path.'wp-load.php');
session_id() || session_start();
nocache_headers();
Header('Content-Type: application/json;charset=utf8');
json_encode(array(
'result' => $_SESSION['ajjx']['cart_obj'], // This in case you want to return something to the caller
));
but here get_cartObj() is not working as expected. No data coming in console.log(data);

Answer 1

The same way you saved it. Actually you can add a parameter to (save)CartObj:
function cartObj(operation, cartObj) {
$.post(
'cartObj.php',
{
op : operation,
cartobj : cartObj
},
function success(data) {
console.log(data);
}
);
}
and in the PHP code (7.4+ required because of the ?? operator)
if ($_POST['operation'] === 'set') {
$_SESSION['ajjx']['cartObj'] = $_POST['cartObj'] ?? [ ];
}
$value = $_SESSION['ajjx']['cartObj'] ?? [ ];
Header('Content-Type: application/json;charset=utf8');
die(json_encode(['result' => $value]));
Now calling the function with 'set' will save the Javascript cart into session, using 'get' will recover the cart.
update
You can also do it like this:
assuming that your page might receive a cart or it might not,
and you will always run the same AJAX code regardless,
then the PHP code must avoid removing the cart if the cartObj parameter is empty (you will need a different call to remove the cart when you need to do this; or you may do it from PHP).
session_id()||session_start();
if ('set' === $_POST['operation'] && !empty($_POST['cartObj'])) {
$_SESSION['ajjx']['cartObj'] = $_POST['cartObj'];
}
Header('Content-Type: application/json;charset=utf8');
die(json_encode(['result'=>$_SESSION['ajjx']['cartObj']??[]]));
This way, if you reload the page but the POSTed cart is now empty (because it's a reload), the AJAX script will not update the session, and it will return the previous session value.

Answer 2

Before im going to answer the question i have some dubt to clear, it looks like you are in a wordpress environment but you are not using his AJAX standard procedures. Check it out here https://codex.wordpress.org/AJAX_in_Plugins
About the issue since JS is client side and PHP is server side you need something to have the values available in JS. I can think of two option:
Print into the page with some PHP a little script tag which is made like this:
<script>
var myObjectVar = '<?php echo json_encode($_SESSION['ajjx']['cart_obj']); ?>';
</script>
You make a new AJAX call as soon as the page load to read that same value from PHP again and then use it to make what you need to do