how to use php sessions and svelte together - php

Question

I'm using php for my application backend. I created a authentication system with two loginUser.php and loginCheck.php
In loginUser.php when username and password is correct:
session_start();
session_regenerate_id();
$_SESSION['bookstore_username'] = $_POST['username'];
session_write_close();
$response = array('status' => true, 'message' => 'user successfully authorized.', 'data' => $row);
echo json_encode($response);
Then in loginCheck.php
session_start();
if (isset($_SESSION["bookstore_username"]) && $_SESSION["bookstore_username"] == $_POST['username']) {
$response = array('status' => true, 'message' => "user is logged in.");
echo json_encode($response);
} else {
$response = array('status' => false, 'message' => "user is not logged in.");
echo json_encode($response);
}
When i testing it in Postman Application everything is fine and response showed me user logged in but in svelte app after doing a user login when i check login stat response is always false and session is null.
const checkUserIsLoggedIn = async (): Promise<void> => {
const url = ORIGIN + "Backend/api/user/loginCheck.php";
let data = new FormData();
data.append("username", userInformationStore?.get().username);
const res = await fetch(url, {
method: "POST",
body: data,
});
let response = await res.json();
console.log(response);
};

Answer 1

Assuming the session relies on a cookie, the only explanation I see for the Session being null is that the session cookie is not being passed back to your back-end. By default, fetch only allows same-origin cookies. Try adding the following option to your fetch operation to allow cookies to be passed in cross-origin requests:
const res = await fetch(url, {
method: "POST",
body: data,
credentials: "include",
});
See this paragraph in the Fetch API documentation for details.