rest-validation

Implement getValidationRuleFor<Verb>() on your Endpoint class returning a ParamRuleCollection with one ParamRule per parameter. Wrap each ParamRule in requiredParamRule or notRequiredParamRule from the ValidationDecorator so absent fields behave correctly.

Use Rules::ENTITY_UNIQUE_PROPERTY with the entity class and property name. For updates, pass an EntityUniquePropertyOption with setIgnoreValues(['id' => $id]) so the current row is excluded from the uniqueness check.

The requiredParamRule decorator treats an empty string as present by default. Pass true as the excludeEmptyString argument so empty strings are treated as missing and fail validation.

ParamRuleCollection is strict by default, so any request parameter without a matching ParamRule is rejected with a 422. Either add a validation rule for that parameter or remove it from the request.

Extend OrangeHRM\Core\Api\V2\Validator\Rules\AbstractRule and implement validate($input): bool, returning false rather than throwing on mismatch. Register the class as a constant in Rules.php, and use EntityManagerHelperTrait if the rule needs database access.