Spring Data Rest Validation Confusion - spring-boot

Question

Looking for some help with Spring data rest validation regarding proper handling of validation errors:
I'm so confused with the docs regarding spring-data-rest validation here: http://docs.spring.io/spring-data/rest/docs/current/reference/html/#validation
I am trying to properly deal with validation for a POST call that tries to save a new Company entity
I got this entity:
#Entity
public class Company implements Serializable {
#Id
#GeneratedValue
private Long id;
#NotNull
private String name;
private String address;
private String city;
private String country;
private String email;
private String phoneNumber;
#OneToMany(cascade = CascadeType.ALL, mappedBy = "company")
private Set<Owner> owners = new HashSet<>();
public Company() {
super();
}
...
and this RestResource dao
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.rest.core.annotation.RestResource;
import com.domain.Company;
#RestResource
public interface CompanyDao extends PagingAndSortingRepository<Company, Long> {
}
POST Request to api/Companies:
{
"address" : "One Microsoft Way",
"city" : "Redmond",
"country" : "USA",
"email" : "info#microsoft.com",
"phoneNumber" : "[phone]"
}
When I issue a POST with a null name , I get the following rest response with httpcode 500
{"timestamp":1455131008472,"status":500,"error":"Internal Server Error","exception":"javax.validation.ConstraintViolationException","message":"Validation failed for classes [com.domain.Company] during persist time for groups [javax.validation.groups.Default, ]\nList of constraint violations:[\n\tConstraintViolationImpl{interpolatedMessage='may not be null', propertyPath=name, rootBeanClass=class com.domain.Company, messageTemplate='{javax.validation.constraints.NotNull.message}'}\n]","path":"/api/companies/"}
I tried creating the following bean, but it never seems to do anything:
#Component(value="beforeCreateCompanyValidator")
public class BeforeCreateCompanyValidator implements Validator{
#Override
public boolean supports(Class<?> clazz) {
return Company.class.isAssignableFrom(clazz);
}
#Override
public void validate(Object arg0, Errors arg1) {
System.out.println("xxxxxxxx");
}
}
and even if it did work, how would it help me in developing a better error response with a proper http code and understandable json response ?
so confused
using 1.3.2.RELEASE
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.3.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

Answer 1

#Mathias
it seems the following is enough for jsr 303 annotations to be checked and for it to auto return a http code of 400 with nice messages (I dont even need BeforeCreateCompanyValidator or BeforeSaveCompanyValidator classes):
#Configuration
public class RestValidationConfiguration extends RepositoryRestConfigurerAdapter{
#Bean
#Primary
/**
* Create a validator to use in bean validation - primary to be able to autowire without qualifier
*/
Validator validator() {
return new LocalValidatorFactoryBean();
}
#Override
public void configureValidatingRepositoryEventListener(ValidatingRepositoryEventListener validatingListener) {
Validator validator = validator();
//bean validation always before save and create
validatingListener.addValidator("beforeCreate", validator);
validatingListener.addValidator("beforeSave", validator);
}
}
400 response:
{
"errors": [{
"entity": "Company",
"message": "may not be null",
"invalidValue": "null",
"property": "name"
}, {
"entity": "Company",
"message": "may not be null",
"invalidValue": "null",
"property": "address"
}]
}

Answer 2

I think your problem is that the bean validation is happening too late - it is done on the JPA level before persist. I found that - unlike spring mvc - spring-data-rest is not doing bean validation when a controller method is invoked. You will need some extra configuration for this.
You want spring-data-rest to validate your bean - this will give you nice error messages responses and a proper http return code.
I configured my validation in spring-data-rest like this:
#Configuration
public class MySpringDataRestValidationConfiguration extends RepositoryRestConfigurerAdapter {
#Bean
#Primary
/**
* Create a validator to use in bean validation - primary to be able to autowire without qualifier
*/
Validator validator() {
return new LocalValidatorFactoryBean();
}
#Bean
//the bean name starting with beforeCreate will result into registering the validator before insert
public BeforeCreateCompanyValidator beforeCreateCompanyValidator() {
return new BeforeCreateCompanyValidator();
}
#Override
public void configureValidatingRepositoryEventListener(ValidatingRepositoryEventListener validatingListener) {
Validator validator = validator();
//bean validation always before save and create
validatingListener.addValidator("beforeCreate", validator);
validatingListener.addValidator("beforeSave", validator);
}
}
When bean validation and/or my custom validator find errors I receive a 400 - bad request with a payload like this:
Status = 400
Error message = null
Headers = {Content-Type=[application/hal+json]}
Content type = application/hal+json
Body = {
"errors" : [ {
"entity" : "siteWithAdminUser",
"message" : "may not be null",
"invalidValue" : "null",
"property" : "adminUser"
} ]
}

Answer 3

The answers by #Mathias and #1977 is enough for regular Spring Data REST calls. However in cases when you need to write custom #RepositoryRestControllers using #RequestBody and #Valid JSR-303 annotations didn't work for me.
So, as an addition to the answer, in case of custom #RepositoryRestControllers with #RequestBody and #Valid annotation I've added the following #ControllerAdvice:
/**
* Workaround class for making JSR-303 annotation validation work for controller method parameters.
* Check the issue DATAREST-593
*/
#ControllerAdvice
public class RequestBodyValidationProcessor extends RequestBodyAdviceAdapter {
private final Validator validator;
public RequestBodyValidationProcessor(#Autowired #Qualifier("mvcValidator") final Validator validator) {
this.validator = validator;
}
#Override
public boolean supports(final MethodParameter methodParameter, final Type targetType, final Class<? extends
HttpMessageConverter<?>> converterType) {
final Annotation[] parameterAnnotations = methodParameter.getParameterAnnotations();
for (final Annotation annotation : parameterAnnotations) {
if (annotation.annotationType().equals(Valid.class)) {
return true;
}
}
return false;
}
#Override
public Object afterBodyRead(final Object body, final HttpInputMessage inputMessage, final MethodParameter
parameter, final Type targetType, final Class<? extends HttpMessageConverter<?>> converterType) {
final Object obj = super.afterBodyRead(body, inputMessage, parameter, targetType, converterType);
final BindingResult bindingResult = new BeanPropertyBindingResult(obj, obj.getClass().getCanonicalName());
validator.validate(obj, bindingResult);
if (bindingResult.hasErrors()) {
throw new RuntimeBindException(bindingResult);
}
return obj;
}
}