PHP cURL proxy with username and password

<?php
// php fetch_proxy.php   (PHP with the curl extension)
$user = getenv("PROXY_USER") . "-country-de";
$pass = getenv("PROXY_PASS");

$ch = curl_init("https://ipinfo.io/json");
curl_setopt_array($ch, [
    CURLOPT_PROXY => "via.proxies.vision:9000",
    CURLOPT_PROXYUSERPWD => "$user:$pass", // the proxy's login; CURLOPT_USERPWD is the website's
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CONNECTTIMEOUT => 15,
    CURLOPT_TIMEOUT => 30,
]);
$body = curl_exec($ch);

if ($body === false) {
    // https:// URLs: a refused tunnel ends here, e.g. "CONNECT tunnel failed, response 407"
    fwrite(STDERR, "curl error " . curl_errno($ch) . ": " . curl_error($ch) . "\n");
    exit(1);
}
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
if ($status === 407) {
    // http:// URLs: the proxy's 407 arrives as an ordinary response, not an error
    fwrite(STDERR, "The proxy rejected the login\n");
    exit(1);
}
echo $status, " ", $body, "\n";

200 {
  "ip": "79.226.48.89",
  "city": "Köln",
  …

<?php
require __DIR__ . "/vendor/autoload.php"; // composer require guzzlehttp/guzzle

use GuzzleHttp\Client;
use GuzzleHttp\Exception\GuzzleException;

$user = getenv("PROXY_USER") . "-country-de";
$pass = getenv("PROXY_PASS");

// One string, not an array: every URL scheme goes through the proxy.
// rawurlencode keeps characters like @ or : in a password from breaking the URL.
$proxy = sprintf("http://%s:%s@via.proxies.vision:9000", rawurlencode($user), rawurlencode($pass));
$client = new Client(["proxy" => $proxy, "timeout" => 30]);

try {
    $r = $client->get("https://ipinfo.io/json");
    echo $r->getStatusCode(), " ", $r->getBody(), "\n";
} catch (GuzzleException $e) {
    // A refused tunnel reads "cURL error 56: CONNECT tunnel failed, response 407"
    fwrite(STDERR, $e->getMessage() . "\n");
    exit(1);
}