<?php
$baseUrl = 'https://shaarli.mydomain.net';
$secret = 'thats_my_api_secret';

function base64url_encode($data) {
  return rtrim(strtr(base64_encode($data), '+/', '-_'), '=');
}

function generateToken($secret) {
    $header = base64url_encode('{
        "typ": "JWT",
        "alg": "HS512"
    }');
    $payload = base64url_encode('{
        "iat": '. time() .'
    }');
    $signature = base64url_encode(hash_hmac('sha512', $header .'.'. $payload , $secret, true));
    return $header . '.' . $payload . '.' . $signature;
}


function getInfo($baseUrl, $secret) {
    $token = generateToken($secret);
    $endpoint = rtrim($baseUrl, '/') . '/api/v1/info';

    $headers = [
        'Content-Type: text/plain; charset=UTF-8',
        'Authorization: Bearer ' . $token,
    ];

    $ch = curl_init($endpoint);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_AUTOREFERER, 1);
    curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);

    $result = curl_exec($ch);
    curl_close($ch);

    return $result;
}

var_dump(getInfo($baseUrl, $secret));