lib/LDAP: Add fetchByDn for a base scope retrieval on an entry

refs #11485

library/Icinga/Protocol/Ldap/LdapConnection.php

@@ -6,6 +6,7 @@ namespace Icinga\Protocol\Ldap;
 use Exception;
 use LogicException;
 use ArrayIterator;
+use stdClass;
 use Icinga\Application\Config;
 use Icinga\Application\Logger;
 use Icinga\Data\ConfigObject;
@@ -549,6 +550,23 @@ class LdapConnection implements Selectable, Inspectable
         return $pairs;
     }
 
+    /**
+     * Fetch an LDAP entry by its DN
+     *
+     * @param  string        $dn
+     * @param  array|null    $fields
+     *
+     * @return StdClass|bool
+     */
+    public function fetchByDn($dn, array $fields = null)
+    {
+        return $this->select()
+            ->from('*', $fields)
+            ->setBase($dn)
+            ->setScope('base')
+            ->fetchRow();
+    }
+
     /**
      * Test the given LDAP credentials by establishing a connection and attempting a LDAP bind
      *