How can I read a cookie I programmatically set?

Question

I can programmatically set a cookie in a Drupal 9 controller and I can see that cookie in Chrome's developer tools. However, I cannot programmatically get that cookie from a hook.

I'm using the SAML Service Provider module. I'm extending the SamlSPDrupalLoginController::initiate() function with this code to set a cookie.

setcookie('stv_saml_idp_id', $idp->get('id'), time() + 86400, '/');

That seems to work fine as I can see the cookie in the Chrome developer tools. Unfortunately, when I attempt to get the cookie back with the following code, I get no results.

function mymodule_saml_sp_drupal_login_user_attributes_alter($user, array $attributes) {
  // …
  $cookies = \Drupal::requestStack()->getCurrentRequest()->cookies;
  $idp_id = $cookies->get('stv_saml_idp_id');
  //…
}

However, if (as a test) I embed the same code in a Basic page, I can get the cookie.

I have also tried with $idp_id = $_COOKIE['stv_saml_idp_id']; but I still could not get the cookie.

How can I read a cookie I programmatically set?

Answer 1

Oh... thanks cilefen. That was a good question that helped me find the problem :-)

I was writing down the attributes to post in reply when I realised my cookie domain differed from the Drupal session cookie domain by 1 character. My cookie domain was:

mysub.domain.com

Whereas, the session cookie had leading dot like so:

.mysub.domain.com

So, the solution was to explicitly set the cookie Domain exactly the same as the Drupal session Domain:

setcookie('stv_saml_idp_id', $idp->get('id'), time() + 86400, '/', '.mysub.domain.com');

Thanks again.