+ @PostMapping
+ public ResponseEntity<Void> getVorgang(
+ ServletUriComponentsBuilder builder,
+ @RequestBody String username) {
+ String cleaned = username.trim().toLowerCase();
+ User user = new User(cleaned, LocalDateTime.now(), false);
+ repository.save(user);
+ // TODO: Not-Unique Fehler auslösen
+ UriComponents uri =
+ builder
+ .fromCurrentRequest()
+ .path("{username}")
+ .buildAndExpand(cleaned);
+ return ResponseEntity.created(uri.toUri()).build();