Say I have a website called a.com, and when a specific page of this site is loaded, say page link, I like to set a cookie for another site called b.com, then redirect the user to b.com.
I mean, on load of a.com/link I want to set a cookie for b.com and redirect user to b.com.
I tested it, and browser actually received the cookie from a.com/link, but it didn't send that cookie on the redirection request to b.com. Is it normal?
Can we set cookies for other domains?
In case you have a.my-company.com and b.my-company.com instead of just a.com and b.com you can issue a cookie for .my-company.com domain - it will be accepted and sent to both of the domains.
Send a POST request from A. Post requests are on the serverside only and can't be accessed by the client.
You can send a POST request from a.com to b.com using CURL (recommended, serverside) or a hidden method="POST" form (clientside). If you go for the latter, you might want to obfuscate your JavaScript so that the user won't be able to understand the algorithm and interfere with it.
Make a gateway on b.com to set cookies:
<?php
if (isset($_POST['data']) {
setcookie('a', $_POST['data']);
header("Location: b.com/landingpage");
}
?>
If you want to bring security a step further, implement a function on both sides (a.com and b.com) to encrypt (on a.com) and decrypt (on b.com) data using a cryptographic cypher.
If you're trying to do something that must be absolutely secure (e.g. transfer a login session) try oAuth or take some inspiration from https://api.cloudianos.com/docs#v2/auth
Here is what I've used. Note, this cookie is passed in the open (http) and is therefore insecure. I don't use it for anything which requires security.
You could probably add encryption/signatures to make this secure. Do your research on how to do that correctly.
In this link, we will find the solution Link.
setcookie("TestCookie", "", time() - 3600, "/~rasmus/", "b.com", 1);