WHOIS & RDAP Lookup — PHP source

<?php
/**
 * RDAP lookup — WHOIS registration data over HTTPS (RFCs 7480-7485).
 *
 * Language: PHP (8.3+, cURL extension)
 * CosmoDev polyglot showcase port of the `whois` tool.
 * Ported from src/lib/whois.ts — display source, part of CosmoDev's
 * polyglot tool pages.
 *
 * RDAP is the JSON successor to port-43 WHOIS. The client first asks
 * IANA's bootstrap registry which server is authoritative for the TLD
 * (dns.json) or the ASN block (asn.json), then fetches the record
 * straight from that server — two HTTPS GETs, no WHOIS port, no backend.
 *
 * Uses cURL, PHP's canonical HTTP client. `array_any()` requires 8.3+.
 */

declare(strict_types=1);

const BOOTSTRAP_URLS = [
    'domain' => 'https://data.iana.org/RDAP/dns.json',
    'autnum' => 'https://data.iana.org/RDAP/asn.json',
];

/**
 * GET a URL over HTTPS and decode the JSON body.
 *
 * @throws RuntimeException On network failure or an HTTP 4xx/5xx response.
 */
function fetch_json(string $url): array
{
    $ch = curl_init($url);
    curl_setopt_array($ch, [
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_CONNECTTIMEOUT => 10,
        CURLOPT_TIMEOUT        => 15,
    ]);
    $body   = curl_exec($ch);
    $status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
    $error  = curl_error($ch);
    curl_close($ch);

    if ($body === false || $error !== '') {
        throw new RuntimeException("request failed: {$error}");
    }
    if ($status >= 400) {
        throw new RuntimeException("HTTP {$status} for {$url}");
    }
    return json_decode($body, true, 512, JSON_THROW_ON_ERROR);
}

/** Classify a query: an AS number ("as3356" / "3356") or a domain name. */
function classify(string $query): array
{
    if (preg_match('/^(?:as)?(\d{1,10})$/i', trim($query), $m) === 1 && (int) $m[1] > 0) {
        return ['kind' => 'autnum', 'value' => (string) (int) $m[1]];
    }
    $value = rtrim(strtolower(trim($query)), '.');
    $tld   = substr($value, strrpos($value, '.') + 1);
    return ['kind' => 'domain', 'value' => $value, 'tld' => $tld];
}

/** True when $asn falls inside an asn.json key ("lo-hi" or a bare number). */
function asn_in_range(string $key, int $asn): bool
{
    if (str_contains($key, '-')) {
        [$lo, $hi] = array_map('intval', explode('-', $key, 2));
        return $asn >= $lo && $asn <= $hi;
    }
    return (int) $key === $asn;
}

/** Ask IANA's bootstrap which RDAP server is authoritative for the query. */
function resolve_rdap_base(array $q): string
{
    $doc = fetch_json(BOOTSTRAP_URLS[$q['kind']]);
    foreach ($doc['services'] as [$keys, $urls]) {
        $hit = $q['kind'] === 'autnum'
            ? array_any($keys, fn ($k) => asn_in_range($k, (int) $q['value']))
            : array_any($keys, fn ($k) => strcasecmp($k, $q['tld']) === 0);
        if ($hit) {
            return $urls[0];
        }
    }
    throw new RuntimeException("no RDAP server for {$q['value']}");
}

/**
 * Look up a domain or ASN over RDAP and pull the essentials: registrar,
 * registration/expiration dates, status flags, and nameservers.
 *
 * @return array{registrar: ?string, registrarEmail: ?string,
 *               registered: ?string, expires: ?string,
 *               status: list<string>, nameservers: list<string>}
 * @throws RuntimeException On network failure or unknown TLD/ASN.
 */
function whois_lookup(string $query): array
{
    $q    = classify($query);
    $base = resolve_rdap_base($q);
    $rdap = fetch_json(rtrim($base, '/') . "/{$q['kind']}/{$q['value']}");

    // Dates are event objects: [{"eventAction": "registration", ...}, ...]
    $dates = [];
    foreach ($rdap['events'] ?? [] as $e) {
        $dates[strtolower($e['eventAction'] ?? '')] = $e['eventDate'] ?? null;
    }

    // The registrar is an entity with role "registrar"; its name and email
    // live inside the jCard array as ["fn", {}, "text", "..."] properties.
    $registrar = null;
    $email     = null;
    foreach ($rdap['entities'] ?? [] as $en) {
        if (!in_array('registrar', $en['roles'] ?? [], true)) {
            continue;
        }
        foreach ($en['vcardArray'][1] ?? [] as $prop) {
            if ($prop[0] === 'fn' && $registrar === null) {
                $registrar = $prop[3];
            }
            if ($prop[0] === 'email' && $email === null) {
                $email = $prop[3];
            }
        }
        break;
    }

    $nameservers = [];
    foreach ($rdap['nameservers'] ?? [] as $ns) {
        if (isset($ns['ldhName'])) {
            $nameservers[] = $ns['ldhName'];
        }
    }

    return [
        'registrar'      => $registrar,
        'registrarEmail' => $email,
        'registered'     => $dates['registration'] ?? null,
        'expires'        => $dates['expiration'] ?? null,
        'status'         => $rdap['status'] ?? [],
        'nameservers'    => $nameservers,
    ];
}

// CLI demo: `php whois.php cosmolabs.org` (or `php whois.php as3356`).
print_r(whois_lookup($argv[1] ?? 'cosmolabs.org'));