Validate required params in views

[efgpinto]

A view with:

  @GetMapping("/wrapped/by_city")
  @Query("""
    SELECT * AS customers, next_page_token() AS token
        FROM customers_by_city
      WHERE address.city = ANY(:cities)
      OFFSET page_token_offset(:pagetoken)
      LIMIT 2
    """)
  public CustomersResponse getCustomers(@RequestParam List<String> cities, @RequestParam String pagetoken) {
    return null;
  }

When called without providing a required param, returns:

✗ curl -i "localhost:9000/wrapped/by_city?cities=Testcity"           
HTTP/1.1 500 Internal Server Error
Access-Control-Allow-Origin: *
Server: akka-http/10.6.0
Date: Thu, 01 Feb 2024 10:00:42 GMT
Content-Type: text/plain; charset=UTF-8
Content-Length: 61

Cannot invoke "Object.getClass()" because "<local14>" is null% 

On the other side, an action with:

  @GetMapping("/actionwrapped/by_city")
  public Effect<CustomersResponse> getCustomers(@RequestParam List<String> cities, @RequestParam String pagetoken) {
    return effects().forward(componentClient.forView().call(CustomersResponseByCity::getCustomers).params(cities, pagetoken));
  }

When called without a required param:

✗ curl -i "localhost:9000/actionwrapped/by_city?cities=Testcity"           
HTTP/1.1 400 Bad Request
Access-Control-Allow-Origin: *
Server: akka-http/10.6.0
Date: Thu, 01 Feb 2024 10:00:58 GMT
Content-Type: text/plain; charset=UTF-8
Content-Length: 48

Required request parameter is missing: pagetoken% 

We want to make it such that the required param is also validated when calling the view directly.