phpcurlhttp2alpn

Remote website ALPN support detection

Is it possible to check the support of ALPN with php curl?

e.g.: if ($is_alpn == true) {echo 'ALPN supported';}

P.S. curl 7.49.0, php 7.0, openssl 1.0.1t

Solution

  • You can just call curl with verbose to see alpn support:

    $cmd = 'curl -X HEAD -v --silent https://comicbooks.world/ 2>&1 | grep "ALPN, offering"';

exec($cmd, $output);

var_dump($output);