Function openssl_pkey_get_details can read this resource. Try:
<?php
print_r(openssl_pkey_get_details(openssl_csr_get_public_key($csr)));
?>
(PHP 5 >= 5.2.0, PHP 7)
openssl_csr_get_public_key — Returns the public key of a CERT
This function is currently not documented; only its argument list is available.
Function openssl_pkey_get_details can read this resource. Try:
<?php
print_r(openssl_pkey_get_details(openssl_csr_get_public_key($csr)));
?>