lib/lti1p3/src/JwksEndpoint.php

   1 <?php
   2
   3 namespace Packback\Lti1p3;
   4
   5 use Firebase\JWT\JWT;
   6 use Packback\Lti1p3\Interfaces\IDatabase;
   7 use Packback\Lti1p3\Interfaces\ILtiRegistration;
   8
   9 class JwksEndpoint
  10 {
  11     public function __construct(private array $keys)
  12     {
  13     }
  14
  15     public static function new(array $keys): self
  16     {
  17         return new JwksEndpoint($keys);
  18     }
  19
  20     public static function fromIssuer(IDatabase $database, string $issuer): self
  21     {
  22         $registration = $database->findRegistrationByIssuer($issuer);
  23
  24         return new JwksEndpoint([$registration->getKid() => $registration->getToolPrivateKey()]);
  25     }
  26
  27     public static function fromRegistration(ILtiRegistration $registration): self
  28     {
  29         return new JwksEndpoint([$registration->getKid() => $registration->getToolPrivateKey()]);
  30     }
  31
  32     public function getPublicJwks(): array
  33     {
  34         $jwks = [];
  35         foreach ($this->keys as $kid => $private_key) {
  36             $key_res = openssl_pkey_get_private($private_key);
  37             $key_details = openssl_pkey_get_details($key_res);
  38             $components = [
  39                 'kty' => 'RSA',
  40                 'alg' => 'RS256',
  41                 'use' => 'sig',
  42                 'e' => JWT::urlsafeB64Encode($key_details['rsa']['e']),
  43                 'n' => JWT::urlsafeB64Encode($key_details['rsa']['n']),
  44                 'kid' => $kid,
  45             ];
  46             $jwks[] = $components;
  47         }
  48
  49         return ['keys' => $jwks];
  50     }
  51 }