How to use

Add this dependency to your Maven pom.xml:

<dependency>
    <groupId>tech.chrigu.hateoas</groupId>
    <artifactId>spring-hateoas-extensions</artifactId>
    <version>0.0.1</version>
</dependency>

Reactive Kotlin extensions/DSL

val link = linkTo<CustomerController> { findById("15") } withRel SELF

val customer = EntityModel.of(Customer("15", "John Doe"))
    .add(CustomerController::class) { entity ->
        linkTo { findById(entity.content!!.id) } withRel SELF
        linkTo { findProductsById(entity.content!!.id) } withRel REL_PRODUCTS
    }
// or
val customer = Mono.just(CustomerModel("15", "John Doe"))
    .add { linkTo<CustomerController> { findById(it.id) } withRel SELF }

With coroutines

val link = linkTo<CustomerController> { findById("15") } awaitRel SELF

Model Assembler

ReactiveEntityModelAssembler

The SimpleReactiveModelAssembler can be hard to use, because its addLinks() functions do not work with reactive types. Hence, if the linkTo() link builder method is used, the model assembler looks like this:

class ObjectModelAssembler : SimpleReactiveRepresentationModelAssembler<Object> {
    override fun toCollectionModel(entities: Flux<out Object>, exchange: ServerWebExchange): Mono<CollectionModel<EntityModel<Object>>> {
        return super.toCollectionModel(entities, exchange)
            .zipWith(getCollectionLink(exchange)) { model, link -> model.add(link) }
    }
// ...
}

With this module, this can be simplified to

class ObjectModelAssembler : ReactiveEntityModelAssembler<Object> {
    override fun getLinks(resources: CollectionModel<EntityModel<Object>>, exchange: ServerWebExchange) = Flux.concat(getCollectionLink(exchange))
// ...
}

ReactivePagedResourcesAssembler

If you need converting Spring Data's Page into PagedModels, you can register a bean of type ReactivePagedResourcesAssemblerArgumentResolver. This will enable controller methods like this:

    @GetMapping
    fun getContracts(
        pageable: Pageable,
        pagedResourcesAssembler: ReactivePagedResourcesAssembler<ContractBaseProperties>,
        exchange: ServerWebExchange
    ): Mono<PagedModel<EntityModel<ContractBaseProperties>>> {
        return contractService.getContracts(pageable)
            .flatMap { pagedResourcesAssembler.toModel(it, contractModelAssembler, exchange) }
    }

SimpleCoroutineRepresentationModelAssembler

This module contains a coroutine alternative for a RepresentationModelAssembler, the CoroutineRepresentationModelAssembler. Likewise, there is the SimpleCoroutineRepresentationModelAssembler alternative that can be used like this:

class ResourceAssemblerWithCustomLink : SimpleCoroutineRepresentationModelAssembler<Employee> {
    override suspend fun addLinks(resource: EntityModel<Employee>, exchange: ServerWebExchange): EntityModel<Employee> {
        return resource.add(Link.of("/employees").withRel("employees"))
    }
}

Release to Maven Central

To make mvn deploy work, your settings.xml should look as follows:

<?xml version="1.0" encoding="UTF-8"?>
<settings xmlns="https://maven.apache.org/SETTINGS/1.0.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="https://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
    <servers>
        <server>
            <id>central</id>
            <username>see https://central.sonatype.com/account</username>
            <password>see https://central.sonatype.com/account</password>
        </server>
    </servers>

    <profiles>
        <profile>
            <id>ossrh</id>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
            <properties>
                <gpg.executable>gpg</gpg.executable>
                <gpg.keyname>see gpg --list-keys and gpg --keyserver keyserver.ubuntu.com --send-keys [KEY_NAME]</gpg.keyname>
                <gpg.passphrase>see gpg --gen-key</gpg.passphrase>
            </properties>
        </profile>
    </profiles>
</settings>