ExternalBackendForm: Remove option to configure where to fetch a remote user

refs #12164

application/forms/Config/UserBackend/ExternalBackendForm.php

@@ -3,7 +3,6 @@
 
 namespace Icinga\Forms\Config\UserBackend;
 
-use Icinga\Authentication\User\ExternalBackend;
 use Zend_Validate_Callback;
 use Icinga\Web\Form;
 
@@ -56,31 +55,6 @@ class ExternalBackendForm extends Form
                 'validators'    => array($callbackValidator)
             )
         );
-
-        $hasRemoteUser = false;
-        foreach (ExternalBackend::$remoteUserEnvvars as $envvar) {
-            if (ExternalBackend::getRemoteUser($envvar) !== null) {
-                $hasRemoteUser = true;
-                break;
-            }
-        }
-        if (! $hasRemoteUser) {
-            $envvar = 'REMOTE_USER';
-        }
-
-        $this->addElement(
-            'text',
-            'username_envvar',
-            array(
-                'label'         => $this->translate('Username Environment Variable'),
-                'description'   => $this->translate(
-                    'The environment variable the webserver assigns the authenticated user\'s name to.'
-                ),
-                'required'      => true,
-                'value'         => $envvar
-            )
-        );
-
         $this->addElement(
             'hidden',
             'backend',

modules/setup/application/forms/AdminAccountPage.php

@@ -270,7 +270,7 @@ class AdminAccountPage extends Form
      */
     protected function getUsername()
     {
-        $name = ExternalBackend::getRemoteUser($this->backendConfig['username_envvar']);
+        list($name, $_) = ExternalBackend::getRemoteUserInformation();
         if ($name === null) {
             return '';
         }

modules/setup/application/forms/AuthenticationPage.php

@@ -32,14 +32,8 @@ class AuthenticationPage extends Form
     public function createElements(array $formData)
     {
         if (isset($formData['type']) && $formData['type'] === 'external') {
-            $hasRemoteUser = false;
+            list($username, $_) = ExternalBackend::getRemoteUserInformation();
-            foreach (ExternalBackend::$remoteUserEnvvars as $envvar) {
+            if ($username === null) {
-                if (ExternalBackend::getRemoteUser($envvar) !== null) {
-                    $hasRemoteUser = true;
-                    break;
-                }
-            }
-            if (! $hasRemoteUser) {
                 $this->info(
                     $this->translate(
                         'You\'re currently not authenticated using any of the web server\'s authentication '