SpringWebFlux Request Validation

Giriş

Eğer WebFlux kullanmıyorsak, ResponseEntityExceptionHandler yazısına bakabiliriz.

Örnek

Elimizde şöyle bir kod olsun

public class FormatNameRequest {

  @NotNull(message = "Title cannot be null")
  private String title;

  @NotNull
  @Size(message = "First name must be between 2 and 25 characters", min = 2, max = 25)
  private String firstName;

  private String middleName;

  @NotBlank(message = "Last name cannot be empty")
  private String lastName;
    ...
}

Şöyle yaparız. Burada @Valid anotasyonundan sonra, post edilen parametre Mono<...> şeklinde kodlanıyor

@RestController
public class ValidationDemoController {

  @PostMapping("/format")
  public Mono<ResponseEntity<FormattedNameResponse>> format(@Valid @RequestBody
    Mono<FormatNameRequest> request) {
    return request
      .map(res -> ResponseEntity.status(HttpStatus.OK).body(alo
FormattedNameResponseMapper.fromFormatNameRequest(res)))
      .onErrorResume(WebExchangeBindException.class,
        ex -> Mono.just(ResponseEntity.status(HttpStatus.BAD_REQUEST)
                  .body(FormattedNameResponseMapper.fromWebExchangeBindException(ex))));
    }
}

public class FormattedNameResponseMapper {

  public static FormattedNameResponse fromWebExchangeBindException(
    WebExchangeBindException ex) {
    FormattedNameResponse res = new FormattedNameResponse();
    List<Error> errors = ex.getFieldErrors().stream()
      .map(fieldError -> new Error(fieldError.getField(), fieldError.getDefaultMessage()))
      .collect(Collectors.toList());
    res.setErrors(errors);
    return res;
  }
  
  public static FormattedNameResponse fromFormatNameRequest(FormatNameRequest req) {
    String s = String.format("%s %s %s %s", req.getTitle(), req.getFirstName(),
    req.getMiddleName(), req.getLastName());
    FormattedNameResponse res = new FormattedNameResponse();
    res.setFormattedName(s);
    return res;
  }
}

Test için şöyle yaparız

Request
POST http://host:port/format
Content-Type: application/json
{
    "title":"Mr",
    "firstName":"Jhon",
    "middleName": "Martin",
    "lastName": "Smith"
}

Succesful Response
200 OK
Content-Type: application/json
{
    "formattedName": "Mr Jhon Martin Smith"
}

Error Response
400 Bad Request
Content-Type: application/json
{
    "errors": [
        {
            "code": "erroCode1",
            "message": "errorMessage1"
        },
        {
            "code": "erroCode2",
            "message": "errorMessage2"
        },
        {
            "code": "erroCode3",
            "message": "errorMessage13"
        }
    ]
}