Proyectos de Subversion Moodle

<?php

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Configurable OAuth2 client class.

 *

 * @package    core_badges

 * @subpackage badges

 * @copyright  2020 Tung Thai

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 * @author     Tung Thai <Tung.ThaiDuc@nashtechglobal.com>

 */

namespace core_badges\oauth2;

defined('MOODLE_INTERNAL') || die();

require_once($CFG->libdir . '/oauthlib.php');

require_once($CFG->libdir . '/filelib.php');

require_once('badge_backpack_oauth2.php');

use moodle_url;

use moodle_exception;

use stdClass;

define('BACKPACK_CHALLENGE_METHOD', 'S256');

define('BACKPACK_CODE_VERIFIER_TIME', 60);

/**

 * Configurable OAuth2 client to request authorization and store token. Use the PKCE method to verifier authorization.

 *

 * @copyright  2020 Tung Thai

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 * @author     Tung Thai <Tung.ThaiDuc@nashtechglobal.com>

 */

class client extends \core\oauth2\client {

    /**  @var \core\oauth2\issuer */

    private $issuer;

    /** @var string $clientid client identifier issued to the client */

    private $clientid = '';

    /** @var string $clientsecret The client secret. */

    private $clientsecret = '';

    /** @var moodle_url $returnurl URL to return to after authenticating */

    private $returnurl = null;

    /** @var string $grantscope */

    protected $grantscope = '';

    /** @var string $scope */

    protected $scope = '';

    /** @var bool basicauth */

    protected $basicauth = true;

    /** @var string|null backpack object */

    public $backpack = '';

    /**

     * client constructor.

     *

     * @param issuer $issuer oauth2 service.

     * @param string $returnurl return url after login

     * @param string $additionalscopes the scopes has been granted

     * @param null $backpack backpack object.

     * @throws \coding_exception error message.

     */

    public function __construct(\core\oauth2\issuer $issuer, $returnurl = '', $additionalscopes = '',

                                $backpack = null) {

        $this->issuer = $issuer;

        $this->clientid = $issuer->get('clientid');

        $this->returnurl = $returnurl;

        $this->clientsecret = $issuer->get('clientsecret');

        $this->backpack = $backpack;

        $this->grantscope = $additionalscopes;

        $this->scope = $additionalscopes;

        parent::__construct($issuer, $returnurl, $additionalscopes, false);

    }

    /**

     * Get login url.

     *

     * @return moodle_url

     * @throws \coding_exception

     * @throws moodle_exception

     */

    public function get_login_url() {

        $callbackurl = self::callback_url();

        $scopes = $this->issuer->get('scopessupported');

        // Removed the scopes does not support in authorization.

        $excludescopes = ['profile', 'openid'];

        $arrascopes = explode(' ', $scopes);

        foreach ($excludescopes as $exscope) {

            $key = array_search($exscope, $arrascopes);

            if (isset($key)) {

                unset($arrascopes[$key]);

            }

        }

        $scopes = implode(' ', $arrascopes);

        $params = array_merge(

            [

                'client_id' => $this->clientid,

                'response_type' => 'code',

                'redirect_uri' => $callbackurl->out(false),

                'state' => $this->returnurl->out_as_local_url(false),

                'scope' => $scopes,

                'code_challenge' => $this->code_challenge(),

                'code_challenge_method' => BACKPACK_CHALLENGE_METHOD,

            ]

        );

        return new moodle_url($this->auth_url(), $params);

    }

    /**

     * Generate code challenge.

     *

     * @return string

     */

    public function code_challenge() {

        $random = bin2hex(openssl_random_pseudo_bytes(43));

        $verifier = $this->base64url_encode(pack('H*', $random));

        $challenge = $this->base64url_encode(pack('H*', hash('sha256', $verifier)));

        $_SESSION['SESSION']->code_verifier = $verifier;

        return $challenge;

    }

    /**

     * Get code verifier.

     *

     * @return bool

     */

    public function code_verifier() {

        if (isset($_SESSION['SESSION']) && !empty($_SESSION['SESSION']->code_verifier)) {

            return $_SESSION['SESSION']->code_verifier;

        }

        return false;

    }

    /**

     * Generate base64url encode.

     *

     * @param string $plaintext text to convert.

     * @return string

     */

    public function base64url_encode($plaintext) {

        $base64 = base64_encode($plaintext);

        $base64 = trim($base64, "=");

        $base64url = strtr($base64, '+/', '-_');

        return ($base64url);

    }

    /**

     * Callback url where the request is returned to.

     *

     * @return moodle_url url of callback

     */

    public static function callback_url() {

        return new moodle_url('/admin/oauth2callback.php');

    }

    /**

     * Check and refresh token to keep login on backpack site.

     *

     * @return bool

     * @throws \coding_exception

     * @throws moodle_exception

     */

    public function is_logged_in() {

        // Has the token expired?

        if (isset($this->accesstoken->expires) && time() >= $this->accesstoken->expires) {

            if (isset($this->accesstoken->refreshtoken)) {

                return $this->upgrade_token($this->accesstoken->refreshtoken, 'refresh_token');

            } else {

                throw new moodle_exception('Could not refresh oauth token, please try again.');

            }

        }

        if (isset($this->accesstoken->token) && isset($this->accesstoken->scope)) {

            return true;

        }

        // If we've been passed then authorization code generated by the

        // authorization server try and upgrade the token to an access token.

        $code = optional_param('oauth2code', null, PARAM_RAW);

        // Note - sometimes we may call is_logged_in twice in the same request - we don't want to attempt

        // to upgrade the same token twice.

        if ($code && $this->upgrade_token($code, 'authorization_code')) {

            return true;

        }

        return false;

    }

    /**

     * Request new token.

     *

     * @param string $code code verify from Auth site.

     * @param string $granttype grant type.

     * @return bool

     * @throws moodle_exception

     */

    public function upgrade_token($code, $granttype = 'authorization_code') {

        $callbackurl = self::callback_url();

        if ($granttype == 'authorization_code') {

            $this->basicauth = true;

            $params = array('code' => $code,

                'grant_type' => $granttype,

                'redirect_uri' => $callbackurl->out(false),

                'scope' => $this->get_scopes(),

                'code_verifier' => $this->code_verifier()

            );

        } else if ($granttype == 'refresh_token') {

            $this->basicauth = false;

            $params = array('refresh_token' => $code,

                'grant_type' => $granttype,

                'scope' => $this->get_scopes(),

            );

        }

        if ($this->basicauth) {

            $idsecret = $this->clientid . ':' . $this->clientsecret;

            $this->setHeader('Authorization: Basic ' . base64_encode($idsecret));

        } else {

            $params['client_id'] = $this->clientid;

            $params['client_secret'] = $this->clientsecret;

        }

        // Requests can either use http GET or POST.

        $response = $this->post($this->token_url(), $this->build_post_data($params));

        if ($this->info['http_code'] !== 200) {

            $debuginfo = !empty($this->error) ? $this->error : $response;

            throw new moodle_exception('oauth2refreshtokenerror', 'core_error', '', $this->info['http_code'], $debuginfo);

        }

        $r = json_decode($response);

        if (is_null($r)) {

            throw new moodle_exception("Could not decode JSON token response");

        }

        if (!empty($r->error)) {

            throw new moodle_exception($r->error . ' ' . $r->error_description);

        }

        if (!isset($r->access_token)) {

            return false;

        }

        // Store the token an expiry time.

        $accesstoken = new stdClass;

        $accesstoken->token = $r->access_token;

        if (isset($r->expires_in)) {

            // Expires 10 seconds before actual expiry.

            $accesstoken->expires = (time() + ($r->expires_in - 10));

        }

        if (isset($r->refresh_token)) {

            $this->refreshtoken = $r->refresh_token;

            $accesstoken->refreshtoken = $r->refresh_token;

        }

        $accesstoken->scope = $r->scope;

        // Also add the scopes.

        $this->store_token($accesstoken);

        return true;

    }

    /**

     * Store a token to verify for send request.

     *

     * @param null|stdClass $token

     */

    protected function store_token($token) {

        global $USER;

        $this->accesstoken = $token;

        // Create or update a DB record with the new token.

        $persistedtoken = badge_backpack_oauth2::get_record(['externalbackpackid' => $this->backpack->id, 'userid' => $USER->id]);

        if ($token !== null) {

            if (!$persistedtoken) {

                $persistedtoken = new badge_backpack_oauth2();

                $persistedtoken->set('issuerid', $this->backpack->oauth2_issuerid);

                $persistedtoken->set('externalbackpackid', $this->backpack->id);

                $persistedtoken->set('userid', $USER->id);

            } else {

                $persistedtoken->set('timemodified', time());

            }

            // Update values from $token. Don't use from_record because that would skip validation.

            $persistedtoken->set('usermodified', $USER->id);

            $persistedtoken->set('token', $token->token);

            $persistedtoken->set('refreshtoken', $token->refreshtoken);

            $persistedtoken->set('expires', $token->expires);

            $persistedtoken->set('scope', $token->scope);

            $persistedtoken->save();

        } else {

            if ($persistedtoken) {

                $persistedtoken->delete();

            }

        }

    }

    /**

     * Get token of current user.

     *

     * @return stdClass|null token object

     */

    protected function get_stored_token() {

        global $USER;

        $token = badge_backpack_oauth2::get_record(['externalbackpackid' => $this->backpack->id, 'userid' => $USER->id]);

        if ($token !== false) {

            $token = $token->to_record();

            return $token;

        }

        return null;

    }

    /**

     * Get scopes granted.

     *

     * @return null|string

     */

    protected function get_scopes() {

        if (!empty($this->grantscope)) {

            return $this->grantscope;

        }

        $token = $this->get_stored_token();

        if ($token) {

            return $token->scope;

        }

        return null;

    }

}