I have UsersController with method:
#RequestMapping(value={"/new"}, method=RequestMethod.GET)
public String showCreationForm(#ModelAttribute User user){
return "user_registration_form";
}
which displays registration form. I want to keep modularity (would be nice to use this controller in some other project) in my project so User is an interface and there is its implementation - UserImpl. The problem is that Spring cannot instatiate User interface. Is there a way to configure spring to use some default implementation of User?
You can provide an object to be populated with request data using #ModelAttribute-annotated method:
#ModelAttribute
public User createUser() {
return new UserImpl();
}
Create a simple class that implements the interface minimally. It is the same idea as an interface, but it is a class. It does not contain any of your logic or validation or anything else. It is just the simplest implementation of the interface, call it UserSimple, and it implements your interface. It is called a Data Transfer Object.
public class UserSimple implements User {
String name;
String address;
//getters and setters only
}
Add a converter that copies the real properties of the UserImpl into the UserSimple.
#Component
public class ImplToSimpleConverter
implements Converter<UserImpl, UserSimple> {
#Override
public UserSimple convert(UserImpl source) {
UserSimple target = new UserSimple();
BeanUtils.copyProperties(source, target);
return target;
}
}
Use UserSimple in the handler.
#RequestMapping(value={"/new"}, method=RequestMethod.GET)
public String showCreationForm(#ModelAttribute UserSimple user){
return "user_registration_form";
}
This allows you to keep the code generic. Adding a different converter is all you would have to do to use the same class in a different application.
Related
I have a question concerning the representation model processors of Spring HATEOAS. We are experimenting to process models before serializing them to the client. Our use case is to enrich the imageUrl field of UserModel objects at runtime, as we have to build the URL based on values from a config bean (AWS S3 bucket URL differs for DEV / PROD setup).
#Data
public class UserModel {
// ...
private String imageUrl;
}
Therefore, we create a UserProcessor to implement this:
public class UserProcessor implements RepresentationModelProcessor<EntityModel<UserModel>> {
private final ConfigAccessor configAccessor;
public UserProcessor(ConfigAccessor configAccessor) {
this.configAccessor = configAccessor;
}
#Override
public EntityModel<UserModel> process(EntityModel<UserModel> model) {
if (model.getContent() != null)
// do the enrichment and set "imageUrl" field
}
return model;
}
}
This works perfectly if we have a controller method like this:
#ResponseBody
#GetMapping("/me")
public EntityModel<UserModel> getCurrentUser(#AuthenticationPrincipal Principal principal) {
UserModel user = ... // get user model
return EntityModel.of(user);
}
However, we are struggling now with the enrichment whenever a UserModel is referenced in another model class, e.g., the BookModel:
#Data
public class BookModel {
private String isbn;
// ...
private EntityModel<UserModel> user; // or "private UserModel user;"
}
A controller method returning type EntityModel<BookModel> only applies the processor for its type, but not for types that are referenced. It seems the processors are not applied recursively.
Is this intentional or are we doing something wrong?
Thanks for any input and help,
Michael
I encountered the same issue and I resolved it by manually assembling resources, in your case that would be implementing RepresentationModelAssembler of the BookModel and then manually invoking the processor on the userModel object that is inside the book.
Make the outer resource a representation model
First consider the BookModel to extend RepresentationModel so that you can manually add links and assemble inner resources (which you would like for the EntityModel<UserModel> object)
#Data
public class BookModel extends RepresentationModel<BookModel> {...}
Write a model assembler
Now write the assembler that takes your book entity and transforms it into a representation model or a collection of these models. You will implement here what EntityModel.of(...) does for you automagically.
#Component
public class BookModelAssembler implements RepresentationModelAssembler<Book, BookModel> {
#Autowired
private UserProcessor userProcessor;
#Override
public BookModel toModel(Book entity) {
var bookModel = new BookModel(entity) // map fields from entity to model
// Transform the user entity to an entity model of user
var user = entity.getUser();
EntityModel<UserModel> userModel = EntityModel.of(user);
userModel = userProcessor.process(userModel);
bookModel.setUserModel(userModel);
return bookModel;
}
}
I might be going out on a limb but I suppose the reason for this is that the processors get invoked when an MVC endpoint returns a type that has a registered processor, which in the case of embedded types is not invoked. My reasoning is based on the docs for RepresentationModelProcessor, which states that processor processes representation models returned from Spring MVC controllers.
I have a not-a-common requirement where I am two different type of consumers for my microservices. One type of consumer is okay with the type-of-response that I am sending them, whereas the other consumer has a requirement where we have to follow their structure (its pretty strict on this).
Lets say I have a StudentController
#RestController
#RequestMapping("/student")
public class StudentController {
#GetMapping("/{name}")
public Student getStudent(#PathVariable String name) {
return Student.builder()
.name(name)
.subjects(List.of("Maths", "English"))
.dateJoined(LocalDate.now().toString())
.build();
}
}
This is alright as one my consumer is accepting my response, where my response looks like this:
{"name":"smit","subjects":["Maths","English"],"dateJoined":"2020-04-26"}
However, the another consumer says that you should sending me the SAME object in a another from something like below:
#RestController
#RequestMapping("/wrapper")
public class WrapperController {
#Autowired
private StudentController studentController;
#GetMapping("/{name}")
public WrapperResponse getStudent(#PathVariable String name){
return WrapperResponse.builder()
.responseTimeStamp(LocalDateTime.now().toString())
.data(studentController.getStudent(name))
.build();
}
}
The below is the output of the above controller.
{"data":{"name":"smit","subjects":["Maths","English"],"dateJoined":"2020-04-26"},"responseTimeStamp":"2020-04-26T01:11:32.986"}
Summary: WrapperController is internally calling StudentController and then wrapping the response in the custom "WrapperResponse" class and then sending that as a response.
Problem: As of now it does solve the problem but I have many such controllers and in my different microservices. So I do not want to rewrite the "WrapperController" for each controller and each microservice.
This is very much opinion-based, but here's how I would refactor this:
Create a Student service (StudentService) that creates the Student,
rather than doing that in the Controller.
Push the code for building a WrapperResponse into the WrapperResponse class itself - either as a static 'factory' method, or as constructor. Have the method take a Student as a parameter.
For each different kind of 'Wrapper' object that you want to supply, have your controller method call the StudentService to get the base Student class, and then construct the Wrapper object by passing the Student to the factory method or constructor of the Wrapper object.
So, your WrapperController might end up looking like this:
#RestController
#RequestMapping("/wrapper")
public class WrapperController {
#Autowired
private StudentService studentService;
#GetMapping("/{name}")
public WrapperResponse getStudent(#PathVariable String name){
return new WrapperResponse(studentService.getStudent(name));
}
}
I'm using springboot security with Okta for authentication. I'm currently trying to create an abstract class implementing OidcUser to encapsulate some methods. For instance:
public abstract class OktaUser implements OidcUser {
public UUID getUserId() {
return UUID.fromString(Objects.requireNonNull(this.getAttribute("user_id")));
}
}
I normaly inject OidcUser (Working)
#GetMapping
public User currentUser(#AuthenticationPrincipal OidcUser oidcUser) {
UUID id = UUID.fromString(Objects.requireNonNull(oidcUser.getAttribute("user_id")));
return userService.getUser(id);
}
But I want to do it like this (Not working)
#GetMapping
public User currentUser(#AuthenticationPrincipal OktaUser oktaUser) {
return userService.getUser(oktaUser.getMicaUserId());
}
However, oktaUser is always null. Is there a way to register OktaUser as AuthenticationPrincipal?
I finally found a solution from this post
With the ControllerAdvice, I was able to build and return my custom OidcUser.
#ModelAttribute
public OktaUser oktaUser(#AuthenticationPrincipal OidcUser oidcUser) {
return oidcUser == null
? null
: new OktaUser(oidcUser.getAuthorities(), oidcUser.getIdToken(), oidcUser.getUserInfo());
}
And i can inject it like that
#GetMapping
public void getAll(#ModelAttribute OktaUser oktaUser) {
}
Take a look at the Spring Security guide:
https://docs.spring.io/spring-security/site/docs/5.2.0.RELEASE/reference/htmlsingle/#mvc-authentication-principal
It walks through exactly this. You can even define your annotation like #MicaUser which would resolve your custom implementation.
I have created a custom controller which needs to convert entities to resources. I have annotated my repositories with #RepositoryRestResource annotation. I want to know if there is a way I can invoke the default functionality of spring Data REST from my custom controller which serializes the entities to resources with links to other entities embedded in them.
I don't want to return entities from my handler method but Resources.
Thanks.
Very simple, using objects Resource or Resources. For example - in this controller we add custom method which return list of all user roles which are enums:
#RepositoryRestController
#RequestMapping("/users/roles")
public class RoleController {
#GetMapping
public ResponseEntity<?> getAllRoles() {
List<Resource<User.Role>> content = new ArrayList<>();
content.addAll(Arrays.asList(
new Resource<>(User.Role.ROLE1),
new Resource<>(User.Role.ROLE2)));
return ResponseEntity.ok(new Resources<>(content));
}
}
To add links to resource you have to use object RepositoryEntityLinks, for example:
#RequiredArgsConstructor
#RepositoryRestController
#RequestMapping("/products")
public class ProductController {
#NonNull private final ProductRepo repo;
#NonNull private final RepositoryEntityLinks links;
#GetMapping("/{id}/dto")
public ResponseEntity<?> getDto(#PathVariable("id") Integer productId) {
ProductProjection dto = repo.getDto(productId);
return ResponseEntity.ok(toResource(dto));
}
private ResourceSupport toResource(ProductProjection projection) {
ProductDto dto = new ProductDto(projection.getProduct(), projection.getName());
Link productLink = links.linkForSingleResource(projection.getProduct()).withRel("product");
Link selfLink = links.linkForSingleResource(projection.getProduct()).slash("/dto").withSelfRel();
return new Resource<>(dto, productLink, selfLink);
}
}
For more example see my 'how-to' and sample project.
I am working on a Spring MVC application and I have the following problem.
I have this RegistrazioneInfo class that contains some information inserted into a form by the user:
public class RegistrazioneInfo {
#NotNull
#Size(min=16, max=16)
private String codiceFiscale;
String gRecaptchaResponse;
public String getCodiceFiscale() {
return codiceFiscale;
}
public void setCodiceFiscale(String codiceFiscale) {
this.codiceFiscale = codiceFiscale;
}
public String getgRecaptchaResponse() {
return gRecaptchaResponse;
}
public void setgRecaptchaResponse(String gRecaptchaResponse) {
this.gRecaptchaResponse = gRecaptchaResponse;
}
}
Then I have this controller class:
#Controller
public class RegistrazioneController extends BaseController {
private RegistrazioneInfo registrazioneInfo;
...............................................
...............................................
...............................................
}
that contains some methods handling request towards some resources.
Ok, my problem is that I want to use an instance of the previous RegistrazioneInfo class as session attribute by the use of the #SessionAttributes Spring annotation as shown here: http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/mvc.html#mvc-ann-sessionattrib
My problem is, in the previous example do something like this:
#SessionAttributes("pet")
public class EditPetForm {
// ...
}
So what exactly is pet? I think that it is something like an id that identify the object that have to be used as a session attribute or something like this. How can I say to put an instance of my RegistrazioneInfo as session attribute?
#SessionAttributes is declared in a Controller Class (#Controller), so on the class level.
Pet is an Bean Object that persist in HttpSession
From the documentation:
This will typically list the names of model attributes which should be transparently stored in the session or some conversational storage, serving as form-backing beans. Declared at the type level, applying to the model attributes that the annotated handler class operates on.
(emphasis is mine)
Also note that, as indicated in the documentation, you should not use that for "non temporary" elements.