Inject parameter into spring-data dynamic query-build methods

Question

I want to know if it's possible to inject some functionality into the dynamically generated CrudRepository query methods to provide an additional filterBy criteria for all methods in a repository.

The short version, I want

    Page<Collection> findByName(@Param("name") String name);

to work as if it were named

    Page<Collection> findByNameAndGroup(@Param("name") String name);

where I add the AndGroup criteria into the generated code for the repo's methods at impl creation time. I don't want to have to add this everywhere, as it will be on all methods, and the parameter is known already.

My initial thought was to extend the repo class, and add some new methods that called the generated ones with the added parameter, but then I realized that the repo is defined only as an interface, so one cannot extend it, and adding any impl would impact the spring-data impl generation. At least, I think that's how it works..

Detail:

I have a MongoRepository that has a lot of API methods generated using the spring-data query-builder syntax. (http://docs.spring.io/spring-data/mongodb/docs/current/reference/html/#repositories.query-methods.query-creation)

Main repo class:

@RepositoryRestResource
public interface CollectionRepository extends MongoRepository<Collection, String> {

    Page<Collection> findByName(@Param("name") String name);
    Page<Collection> findByNameRegex(@Param("name") String name);
    // lots more findBy methods here...
}

The repo objects, collections, are just an object with a name and a group Id:

@Document
public class Collection {
    private String name;
    private String group;
}

My authenticated user objects are:

@Document
public class Collection {
    private String username;
    private String password;
    private String group;
}

The user's group needs to filter what collections a user can see, in all cases.

Every one of the above findBy...() needs to become a findBy...AndGroup(), which is possible because the group is an element in the collection.

The easy way is to simply add the new parameter to every one of the methods, ie:

@RepositoryRestResource
public interface CollectionRepository extends MongoRepository<Collection, String> {

    Page<Collection> findByNameAndGroup(@Param("name") String name);
    Page<Collection> findByNameRegexAndGroup(@Param("name") String name);
    // lots more methods here...
}

This also makes the client needlessly pass in a parameter that is already known from the user's context.

If I wasn't using spring-data and I had to actually write code for the controllers I'd call a method from all API handlers that read the user's group:

  User user = (User)SecurityContextHolder.getContext().getAuthentication().getPrincipal();
  String group = user.getGroup();

and added it to calling method's filterBy criteria.

Is it possible to wire this functionality into the spring-data infrastructure such that the generated find...() methods for this interface add the "...ByGoup" criteria to all methods, and pass in a method to use to extract this group parameter?

To say it another way, can I alter the repository instance to affect all the generated methods to extract the user's group using a provided method, add this ByGroup filter to the initial criteria that spring generates based on the method name?

Could one use aspectJ to wire in a a pre/post method handler to do this?

Answer 1

Currently there's no direct support for that. Spring Data JPA already has support to use SpEL expressions in manual query definitions so that e.g. Spring Security specific functions can be used to in JPQL queries. This is shown in this example project but requires manual definition of the queries.

We're currently working on a mechanism to provide means to augment all queries executed by Spring Data. Be sure to follow DATACMNS-293 for the fundamental infrastructure as well as DATAJPA-307 for an example implementation of soft-deletes on top of that.

For DATACMNS-293 we already provide feature branch builds so that you could try to build your own QueryAugmentor. AnnotationBasedQueryAugmentor is probably type you want to look into.