[Summary view]

   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  namespace core\oauth2\discovery;
  18  
  19  use core\http_client;
  20  use GuzzleHttp\Exception\ClientException;
  21  
  22  /**
  23   * Simple reader class, allowing OAuth 2 Authorization Server Metadata to be read from an auth server's well-known.
  24   *
  25   * {@link https://www.rfc-editor.org/rfc/rfc8414}
  26   *
  27   * @package    core
  28   * @copyright  2023 Jake Dallimore <jrhdallimore@gmail.com>
  29   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  30   */
  31  class auth_server_config_reader {
  32  
  33      /** @var \stdClass the config object read from the discovery document. */
  34      protected \stdClass $metadata;
  35  
  36      /** @var \moodle_url the base URL for the auth server which was last used during a read.*/
  37      protected \moodle_url $issuerurl;
  38  
  39      /**
  40       * Constructor.
  41       *
  42       * @param http_client $httpclient an http client instance.
  43       * @param string $wellknownsuffix the well-known suffix, defaulting to 'oauth-authorization-server'.
  44       */
  45      public function __construct(protected http_client $httpclient,
  46          protected string $wellknownsuffix = 'oauth-authorization-server') {
  47      }
  48  
  49      /**
  50       * Read the metadata from the remote host.
  51       *
  52       * @param \moodle_url $issuerurl the auth server issuer URL.
  53       * @return \stdClass the configuration data object.
  54       * @throws ClientException|\GuzzleHttp\Exception\GuzzleException if the http client experiences any problems.
  55       */
  56      public function read_configuration(\moodle_url $issuerurl): \stdClass {
  57          $this->issuerurl = $issuerurl;
  58          $this->validate_uri();
  59  
  60          $url = $this->get_configuration_url()->out(false);
  61          $response = $this->httpclient->request('GET', $url);
  62          $this->metadata = json_decode($response->getBody());
  63          return $this->metadata;
  64      }
  65  
  66      /**
  67       * Make sure the base URI is suitable for use in discovery.
  68       *
  69       * @return void
  70       * @throws \moodle_exception if the URI fails validation.
  71       */
  72      protected function validate_uri() {
  73          if (!empty($this->issuerurl->get_query_string())) {
  74              throw new \moodle_exception('Error: '.__METHOD__.': Auth server base URL cannot contain a query component.');
  75          }
  76          if (strtolower($this->issuerurl->get_scheme()) !== 'https') {
  77              throw new \moodle_exception('Error: '.__METHOD__.': Auth server base URL must use HTTPS scheme.');
  78          }
  79          // This catches URL fragments. Since a query string is ruled out above, out_omit_querystring(false) returns only fragments.
  80          if ($this->issuerurl->out_omit_querystring() != $this->issuerurl->out(false)) {
  81              throw new \moodle_exception('Error: '.__METHOD__.': Auth server base URL must not contain fragments.');
  82          }
  83      }
  84  
  85      /**
  86       * Get the Auth server metadata URL.
  87       *
  88       * Per {@link https://www.rfc-editor.org/rfc/rfc8414#section-3}, if the issuer URL contains a path component,
  89       * the well known suffix is added between the host and path components.
  90       *
  91       * @return \moodle_url the full URL to the auth server metadata.
  92       */
  93      protected function get_configuration_url(): \moodle_url {
  94          $path = $this->issuerurl->get_path();
  95          if (!empty($path) && $path !== '/') {
  96              // Insert the well known suffix between the host and path components.
  97              $port = $this->issuerurl->get_port() ? ':'.$this->issuerurl->get_port() : '';
  98              $uri = $this->issuerurl->get_scheme() . "://" . $this->issuerurl->get_host() . $port ."/".
  99                  ".well-known/" . $this->wellknownsuffix . $path;
 100          } else {
 101              // No path, just append the well known suffix.
 102              $uri = $this->issuerurl->out(false);
 103              $uri .= (substr($uri, -1) == '/' ? '' : '/');
 104              $uri .= ".well-known/$this->wellknownsuffix";
 105          }
 106  
 107          return new \moodle_url($uri);
 108      }
 109  }