sdk/php | XID

PHP 8.1+ server SDK for networkless JWT verification, PSR-7 request authentication, and webhook signature validation.

Status

Implemented and verified locally. Real IdP round-trip verification (JWKS fetch, token sign/verify against a live XID instance) has not been performed yet and must be completed before production use.

Install

PHP 8.1+ required. Core dependencies are pulled automatically by Composer.

composer require xid/xid

Quick start

use Xid\XidClient;
use Xid\Exception\TokenException;
use Xid\Exception\JwksException;

$xid = new XidClient([
    'issuer'   => 'https://xid.dev',
    'audience' => 'your-client-id',
    'cache'    => $psrSimpleCacheImpl, // PSR-16; null disables JWKS cache
]);

try {
    $claims = $xid->verifyToken($jwtString);
    echo $claims->sub();    // user ID
    echo $claims->scope();  // "openid profile email"
    echo implode(',', $claims->amr()); // "phr" / "otp"
} catch (TokenException $e) {
    http_response_code(401);
} catch (JwksException $e) {
    http_response_code(503);
}

Authenticate a PSR-7 request

$result = $xid->authenticateRequest($psrRequest);

if ($result->isAuthenticated()) {
    $userId = $result->claims()->sub();
} else {
    // $result->reason() for server-side logs only
    http_response_code(401);
}

Verify webhook

use Xid\Exception\WebhookException;

try {
    $payload = $xid->verifyWebhook($psrRequest, 'whsec_...');
    $type = $payload->type();  // "user.created"
    $data = $payload->data();
} catch (WebhookException $e) {
    http_response_code(400);
}

XidClient options

Key	Default	Description
`issuer`	required	XID issuer URI
`audience`	`null`	Expected audience; null skips validation
`cache`	`null`	PSR-16 CacheInterface for JWKS caching
`jwks_ttl`	`3600`	JWKS cache TTL in seconds
`clock_leeway`	`0`	JWT clock skew tolerance in seconds
`cookie_name`	`__xid_session`	Session cookie key for token extraction

XidClient methods

Method	Returns	Description
`verifyToken(string $token)`	`Claims`	Verify JWT string; throws on failure
`authenticateRequest(ServerRequestInterface $request)`	`AuthResult`	Authenticate PSR-7 request; does not throw
`verifyWebhook(ServerRequestInterface $request, string $secret)`	`WebhookPayload`	Validate webhook signature; throws on failure
`refreshJwks()`	`void`	Force-refresh the JWKS cache

Platform notes

Uses firebase/php-jwt for ES256/RS256 verification. HS256 and none alg are rejected.
Requires a PSR-7 request object for authenticateRequest and verifyWebhook. Convert framework-native requests with a PSR-7 bridge if needed.
Exception hierarchy: XidException -> TokenException, JwksException, WebhookException.