user_saml/appinfo/app.php

<?php
/**
 * @copyright Copyright (c) 2016 Lukas Reschke <lukas@statuscode.ch>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

require_once __DIR__ . '/../3rdparty/vendor/autoload.php';

// If we run in CLI mode do not setup the app as it can fail the OCC execution
// since the URLGenerator isn't accessible.
if(OC::$CLI) {
	return;
}


$urlGenerator = \OC::$server->getURLGenerator();
$config = \OC::$server->getConfig();
$request = \OC::$server->getRequest();
$userSession = \OC::$server->getUserSession();
$samlSettings = new \OCA\User_SAML\SAMLSettings(
	$urlGenerator,
	$config
);

$userBackend = new \OCA\User_SAML\UserBackend(
	$config,
	$urlGenerator,
	\OC::$server->getSession(),
	\OC::$server->getDb()
);
$userBackend->registerBackends(\OC::$server->getUserManager()->getBackends());
OC_User::useBackend($userBackend);
OC_User::handleApacheAuth();

// Setting up the one login config may fail, if so, do not catch the requests later.
$returnScript = false;
$type = '';
switch($config->getAppValue('user_saml', 'type')) {
	case 'saml':
		try {
			$oneLoginSettings = new \OneLogin_Saml2_Settings($samlSettings->getOneLoginSettingsArray());
		} catch (OneLogin_Saml2_Error $e) {
			$returnScript = true;
		}
		$type = 'saml';
		break;
	case 'environment-variable':
		\OC::$server->getSession()->set('user_saml.samlUserData', $_SERVER);
		$type = 'environment-variable';
		break;
}

if($returnScript === true) {
	return;
}

$redirectSituation = false;
// All requests that are not authenticated and match against the "/login" route are
// redirected to the SAML login endpoint
if(!$userSession->isLoggedIn() &&
	\OC::$server->getRequest()->getPathInfo() === '/login' &&
	$type === 'saml') {
	$redirectSituation = true;
}

// If a request to OCS or remote.php is sent by the official desktop clients it can
// be intercepted as it supports SAML. All other clients don't yet and thus we
// require the usage of application specific passwords there.
//
// However, it is an opt-in setting to use SAML for the desktop clients. For better
// UX (users don't have to reauthenticate) we default to disallow the access via
// SAML at the moment.
$useSamlForDesktopClients = $config->getAppValue('user_saml', 'general-use_saml_auth_for_desktop', '0');
if($useSamlForDesktopClients === '1') {
	$currentUrl = substr(explode('?',$request->getRequestUri(), 2)[0], strlen(\OC::$WEBROOT));
	if(substr($currentUrl, 0, 12) === '/remote.php/' || substr($currentUrl, 0, 5) === '/ocs/') {
		if(!$userSession->isLoggedIn() && $request->isUserAgent([\OC\AppFramework\Http\Request::USER_AGENT_OWNCLOUD_DESKTOP])) {
			$redirectSituation = true;
		}
	}
}

if($redirectSituation === true) {
	$csrfToken = \OC::$server->getCsrfTokenManager()->getToken();
	header('Location: '.$urlGenerator->linkToRouteAbsolute('user_saml.SAML.login') .'?requesttoken='. urlencode($csrfToken->getEncryptedValue()));
	exit();
}