PHP のストリーム関数で簡易 HTTP/2 クライアント (SETTINGS まで)

README.md

PHP のストリーム関数で簡易 HTTP/2 クライアント (SETTINGS まで)

実行結果

target: tls://142.250.192.164:443 (SNI/peer_name=www.google.com)
alpn_protocols(configured): h2,http/1.1
ALPN (negotiated): h2
>>> sending client preface (24 bytes)
>>> sending SETTINGS (empty payload)
FRAME #0 len=18 type=0x04(SETTINGS) flags=0x00 sid=0
0000  00 03 00 00 00 64 00 04 00 10 00 00 00 06 00 01  .....d..........
0010  00 00                                            ..

>>> sending SETTINGS ACK
SETTINGS exchange done; exiting demo.
done

client.php

<?php
declare(strict_types=1);

error_reporting(E_ALL);
ini_set('display_errors', '1');

function logln(string $s): void {
    fwrite(STDOUT, $s . PHP_EOL);
    fflush(STDOUT);
}

function hexdump(string $bin, int $max = 256): string {
    $len = strlen($bin);
    $n = min($len, $max);
    $out = '';
    for ($i = 0; $i < $n; $i += 16) {
        $chunk = substr($bin, $i, 16);
        $hex = implode(' ', str_split(bin2hex($chunk), 2));
        $ascii = preg_replace('/[^\x20-\x7e]/', '.', $chunk);
        $out .= sprintf("%04x  %-47s  %s\n", $i, $hex, $ascii);
    }
    if ($len > $max) {
        $out .= sprintf("... (%d bytes total)\n", $len);
    }
    return $out;
}

/**
 * read exactly $n bytes; returns null on timeout/EOF/error
 */
function readN($fp, int $n): ?string {
    $buf = '';
    while (strlen($buf) < $n) {
        $r = fread($fp, $n - strlen($buf));
        if ($r === false) {
            return null;
        }
        if ($r === '') {
            $m = stream_get_meta_data($fp);
            if (!empty($m['timed_out']) || feof($fp)) {
                return null;
            }
            usleep(10_000);
            continue;
        }
        $buf .= $r;
    }
    return $buf;
}

/**
 * HTTP/2 frame:
 *  length(24) type(8) flags(8) r(1)+stream_id(31) payload(length)
 */
function readFrame($fp): ?array {
    $h = readN($fp, 9);
    if ($h === null || strlen($h) < 9) return null;

    $len   = (ord($h[0]) << 16) | (ord($h[1]) << 8) | ord($h[2]);
    $type  = ord($h[3]);
    $flags = ord($h[4]);
    $sid   = (unpack('N', substr($h, 5, 4))[1]) & 0x7FFFFFFF;

    $payload = $len ? readN($fp, $len) : '';
    if ($len && ($payload === null || strlen($payload) < $len)) return null;

    return [$len, $type, $flags, $sid, $payload];
}

function packFrame(int $type, int $flags, int $sid, string $payload): string {
    $len = strlen($payload);
    $h = chr(($len >> 16) & 0xff) . chr(($len >> 8) & 0xff) . chr($len & 0xff);
    $h .= chr($type & 0xff) . chr($flags & 0xff);
    $h .= pack('N', $sid & 0x7FFFFFFF);
    return $h . $payload;
}

function nameFrameType(int $t): string {
    return match ($t) {
        0x00 => 'DATA',
        0x01 => 'HEADERS',
        0x02 => 'PRIORITY',
        0x03 => 'RST_STREAM',
        0x04 => 'SETTINGS',
        0x05 => 'PUSH_PROMISE',
        0x06 => 'PING',
        0x07 => 'GOAWAY',
        0x08 => 'WINDOW_UPDATE',
        0x09 => 'CONTINUATION',
        default => 'UNKNOWN',
    };
}

function connectTlsWithAlpn(string $host, int $port, string $alpn, int $timeoutSec = 3) {
    // IPv6 でハングしがちな環境向け：IPv4を優先（取れないならホスト名のまま）
    $ip4 = gethostbyname($host);
    $targetHost = ($ip4 !== $host) ? $ip4 : $host;
    $target = "tls://{$targetHost}:{$port}";

    $ctx = stream_context_create([
        'ssl' => [
            'verify_peer'      => true,
            'verify_peer_name' => true,
            'SNI_enabled'      => true,
            'peer_name'        => $host, // SNI はホスト名で
            'alpn_protocols'   => $alpn,
        ],
    ]);

    logln("target: {$target} (SNI/peer_name={$host})");
    logln("alpn_protocols(configured): {$alpn}");

    $errno = 0; $errstr = '';
    $fp = @stream_socket_client($target, $errno, $errstr, $timeoutSec, STREAM_CLIENT_CONNECT, $ctx);
    if (!$fp) {
        throw new RuntimeException("connect failed: ($errno) $errstr");
    }

    // 重要：タイムアウト・バッファを明示
    stream_set_timeout($fp, $timeoutSec);
    stream_set_read_buffer($fp, 0);
    stream_set_write_buffer($fp, 0);

    $meta = stream_get_meta_data($fp);
    $neg = null;
    if (isset($meta['crypto']) && is_array($meta['crypto'])) {
        foreach (['alpn_protocol','alpn_selected','ssl_alpn_protocol','negotiated_protocol','protocol'] as $k) {
            if (isset($meta['crypto'][$k]) && is_string($meta['crypto'][$k]) && $meta['crypto'][$k] !== '') {
                $neg = $meta['crypto'][$k];
                break;
            }
        }
    }

    logln("ALPN (negotiated): " . ($neg ?? "(not found; check meta dump)"));

    return [$fp, $meta, $neg];
}

/* ========= main ========= */

$host = $argv[1] ?? 'www.google.com';
$port = (int)($argv[2] ?? 443);

// h2 が選ばれるかを見る。順序は h2 優先。
$alpn = "h2,http/1.1";

// ここは用途に応じて。デモなので短め。
$timeoutSec = 2;

try {
    [$fp, $meta, $neg] = connectTlsWithAlpn($host, $port, $alpn, $timeoutSec);
} catch (Throwable $e) {
    logln("[!] " . $e->getMessage());
    exit(1);
}

if ($neg !== 'h2') {
    logln("[!] negotiated ALPN is not h2. Exiting (this demo expects HTTP/2).");
    // 必要なら meta を見たいときだけ出す
    // var_export($meta); echo PHP_EOL;
    fclose($fp);
    exit(2);
}

// 1) client connection preface（必須）
$preface = "PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n";
logln(">>> sending client preface (" . strlen($preface) . " bytes)");
fwrite($fp, $preface);

// 2) クライアント SETTINGS（最小：空payloadでもOK）
$settings = packFrame(0x04, 0x00, 0, '');
logln(">>> sending SETTINGS (empty payload)");
fwrite($fp, $settings);

// 3) サーバからの SETTINGS 等を読む
$gotServerSettings = false;
$ackedServerSettings = false;

$maxFrames = 50;
for ($i = 0; $i < $maxFrames; $i++) {
    $fr = readFrame($fp);
    if ($fr === null) {
        $m = stream_get_meta_data($fp);
        logln("no more frames / timeout=" . (!empty($m['timed_out']) ? 'yes' : 'no') . " eof=" . (feof($fp) ? 'yes' : 'no'));
        break;
    }

    [$len, $type, $flags, $sid, $payload] = $fr;
    $tname = nameFrameType($type);
    logln(sprintf("FRAME #%d len=%d type=0x%02x(%s) flags=0x%02x sid=%d", $i, $len, $type, $tname, $flags, $sid));

    if ($len > 0) {
        // SETTINGSのpayloadは6バイト単位のID/Valueだが、デモではダンプだけ
        logln(hexdump($payload, 256));
    }

    // サーバ SETTINGS（ACKではない）を受けたら ACK を返す
    if ($type === 0x04 /*SETTINGS*/ && ($flags & 0x01) === 0) {
        $gotServerSettings = true;
        if (!$ackedServerSettings) {
            $ack = packFrame(0x04, 0x01, 0, '');
            logln(">>> sending SETTINGS ACK");
            fwrite($fp, $ack);
            $ackedServerSettings = true;

            // 疎通確認としてはここで終わるのが現実的
            logln("SETTINGS exchange done; exiting demo.");
            break;
        }
    }

    // 念のため：GOAWAY が来たら終わり
    if ($type === 0x07 /*GOAWAY*/) {
        logln("GOAWAY received; exiting.");
        break;
    }
}

fclose($fp);
logln("done");