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     private $keys;
  12
  13     public function __construct(array $keys)
  14     {
  15         $this->keys = $keys;
  16     }
  17
  18     public static function new(array $keys)
  19     {
  20         return new JwksEndpoint($keys);
  21     }
  22
  23     public static function fromIssuer(IDatabase $database, $issuer)
  24     {
  25         $registration = $database->findRegistrationByIssuer($issuer);
  26
  27         return new JwksEndpoint([$registration->getKid() => $registration->getToolPrivateKey()]);
  28     }
  29
  30     public static function fromRegistration(ILtiRegistration $registration)
  31     {
  32         return new JwksEndpoint([$registration->getKid() => $registration->getToolPrivateKey()]);
  33     }
  34
  35     public function getPublicJwks()
  36     {
  37         $jwks = [];
  38         foreach ($this->keys as $kid => $private_key) {
  39             $key_res = openssl_pkey_get_private($private_key);
  40             $key_details = openssl_pkey_get_details($key_res);
  41             $components = [
  42                 'kty' => 'RSA',
  43                 'alg' => 'RS256',
  44                 'use' => 'sig',
  45                 'e' => JWT::urlsafeB64Encode($key_details['rsa']['e']),
  46                 'n' => JWT::urlsafeB64Encode($key_details['rsa']['n']),
  47                 'kid' => $kid,
  48             ];
  49             $jwks[] = $components;
  50         }
  51
  52         return ['keys' => $jwks];
  53     }
  54
  55     public function outputJwks()
  56     {
  57         echo json_encode($this->getPublicJwks());
  58     }
  59 }