composer/composer · error · \RuntimeException

unable to find proxy host in

Error message

unable to find proxy host in {$envName}

What it means

The proxy URL parsed via parse_url but produced no `host` component, so Composer cannot route traffic. Reported at src/Composer/Util/Http/ProxyItem.php:48 as 'unable to find proxy host in <envName>'.

Solutions

1. Add the host: `http://proxy.example.com:8080`.
2. If using a Unix-socket proxy, switch to a supported TCP host (Composer/curl need a hostname).
3. Clear the env var if it was set unintentionally.

Example fix

# before
HTTPS_PROXY="http://:3128"

# after
HTTPS_PROXY="http://squid.example.com:3128"

$p = parse_url(getenv('HTTPS_PROXY') ?: '');
if (is_array($p) && !isset($p['host'])) {
    throw new \InvalidArgumentException('HTTPS_PROXY has no host.');
}

try {
    $proxy = new \Composer\Util\Http\ProxyItem($val, 'HTTPS_PROXY');
} catch (\RuntimeException $e) {
    if (str_starts_with($e->getMessage(), 'unable to find proxy host in')) {
        // fix the URL to include a host, then retry
    }
    throw $e;
}

When it happens

Trigger: Values like `http://:8080`, `http:///path`, or a bare scheme `http://` — parse_url succeeds but $proxy['host'] is unset (line 47).

Common situations: Misformatted proxy strings missing the hostname; port-only values; proxy set to a bare scheme by mistake.

Related errors

• port 0 is reserved in
• unable to find proxy port in
• unsupported ` ` syntax
• Invalid value for COMPOSER_AUDIT_ABANDONED
• You must enable the curl extension to make https requests…

AI-assisted analysis of composer/composer@c435d285c9 (2026-08-07). Data as JSON: /api/errors/82e9d2df9249dd19. Report an issue: GitHub.

Appendix: source

Thrown at src/Composer/Util/Http/ProxyItem.php:48

    private $optionsAuth;

    /**
     * @param string $proxyUrl The value from the environment
     * @param string $envName The name of the environment variable
     * @throws \RuntimeException If the proxy url is invalid
     */
    public function __construct(string $proxyUrl, string $envName)
    {
        $syntaxError = sprintf('unsupported `%s` syntax', $envName);

        if (strpbrk($proxyUrl, "\r\n\t") !== false) {
            throw new \RuntimeException($syntaxError);
        }
        if (false === ($proxy = parse_url($proxyUrl))) {
            throw new \RuntimeException($syntaxError);
        }
        if (!isset($proxy['host'])) {
            throw new \RuntimeException('unable to find proxy host in ' . $envName);
        }

        $scheme = isset($proxy['scheme']) ? strtolower($proxy['scheme']) . '://' : 'http://';
        $safe = '';

        if (isset($proxy['user'])) {
            $safe = '***';
            $user = $proxy['user'];
            $auth = rawurldecode($proxy['user']);

            if (isset($proxy['pass'])) {
                $safe .= ':***';
                $user .= ':' . $proxy['pass'];
                $auth .= ':' . rawurldecode($proxy['pass']);
            }

            $safe .= '@';

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