Make configuration of custom user-group backends possible

refs #2840

application/forms/Config/UserGroup/UserGroupBackendForm.php

@@ -27,6 +27,13 @@ class UserGroupBackendForm extends ConfigForm
      */
     protected $backendToLoad;
 
+    /**
+     * Known custom backends
+     *
+     * @var array
+     */
+    protected $customBackends;
+
     /**
      * Create a user group backend by using the given form's values and return its inspection results
      *
@@ -51,6 +58,7 @@ class UserGroupBackendForm extends ConfigForm
     {
         $this->setName('form_config_usergroupbackend');
         $this->setSubmitLabel($this->translate('Save Changes'));
+        $this->customBackends = UserGroupBackend::getCustomBackendConfigForms();
     }
 
     /**
@@ -71,6 +79,10 @@ class UserGroupBackendForm extends ConfigForm
             case 'msldap':
                 return new LdapUserGroupBackendForm();
             default:
+                if (isset($this->customBackends[$type])) {
+                    return new $this->customBackends[$type]();
+                }
+
                 throw new InvalidArgumentException(
                     sprintf($this->translate('Invalid backend type "%s" provided'), $type)
                 );
@@ -174,13 +186,15 @@ class UserGroupBackendForm extends ConfigForm
      */
     public function createElements(array $formData)
     {
-        // TODO(jom): We did not think about how to configure custom group backends yet!
         $backendTypes = array(
             'db'        => $this->translate('Database'),
             'ldap'      => 'LDAP',
             'msldap'    => 'ActiveDirectory'
         );
 
+        $customBackendTypes = array_keys($this->customBackends);
+        $backendTypes += array_combine($customBackendTypes, $customBackendTypes);
+
         $backendType = isset($formData['type']) ? $formData['type'] : null;
         if ($backendType === null) {
             $backendType = key($backendTypes);

library/Icinga/Authentication/UserGroup/UserGroupBackend.php

@@ -68,6 +68,22 @@ class UserGroupBackend
         }
     }
 
+    /**
+     * Get config forms of all custom user group backends
+     */
+    public static function getCustomBackendConfigForms()
+    {
+        $customBackendConfigForms = [];
+        static::registerCustomUserGroupBackends();
+        foreach (self::$customBackends as $customBackendType => $customBackendClass) {
+            if (method_exists($customBackendClass, 'getConfigurationFormClass')) {
+                $customBackendConfigForms[$customBackendType] = $customBackendClass::getConfigurationFormClass();
+            }
+        }
+
+        return $customBackendConfigForms;
+    }
+
     /**
      * Return the class for the given custom user group backend
      *

library/Icinga/Authentication/UserGroup/UserGroupBackendInterface.php

@@ -43,4 +43,14 @@ interface UserGroupBackendInterface
      * @return  null|string     The name of the backend or null in case this information is not available
      */
     public function getUserBackendName($username);
+
+    /**
+     * Return this backend's configuration form class path
+     *
+     * This is not part of the interface to not break existing implementations.
+     * If you need a custom backend form, implement this method.
+     *
+     * @return string
+     */
+    //public static function getConfigurationFormClass();
 }