MicroProfile Rest Client adds the capability to invoke remote microservices using a JAX-RS like interface to declare the operations.

To use the rest client in your project, declare the following dependency:

<dependency>
    <groupId>io.helidon.microprofile.rest-client</groupId>
    <artifactId>helidon-microprofile-rest-client</artifactId>
</dependency>

MicroProfile Rest Client can be created using a builder obtained from RestClientBuilder.newBuilder(). The builder provides methods to configure details for the client and to define the desired rest client interface.

Example:

SomeResource someResource = RestClientBuilder.newBuilder()
                                 .baseUri(URI.create("http://localhost:8080/baseUri"))
                                 .build(SomeResource.class);

someResource.someMethod(apiModel);

A rest client interface can be annotated with @RegisterRestClient to automatically register it with CDI. The RegisterRestClient annotation has a property baseUri that can be used to define the base endpoint of this client. This value can be overridden using configuration.

Example:

@RegisterRestClient(baseUri="http://localhost:8080/baseUri")
public interface SomeResource {

// ...

}

Once a rest client interface is annotated, it can be injected into any CDI bean.

Example:

@Inject
@RestClient
SomeResource client;

// ...

client.sampleMethod();

Rest client implementation allows you to configure its parameters by builder, annotations, and configuration.

You can configure new providers, base URI/URL and other options of the client. See specification for full details: https://download.eclipse.org/microprofile/microprofile-rest-client-1.2.1/microprofile-rest-client-1.2.1.html

To be able to run and test this example, please head to the Helidon examples/quickstarts and start the helidon-quickstart-mp. Then create project with the dependency on the Helidon rest client implementation and create the following rest client interface:

Rest client interface

@Path("/greet")
interface GreetRestClient {

     @GET
     JsonObject getDefaultMessage();

     @Path("/{name}")
     @GET
     JsonObject getMessage(@PathParam("name") String name);

}

Then create runnable method the same way as it is described in Creating new client - Interface,but with baseUri http://localhost:8080/greet and the above interface.

By calling GreetRestClient.getDefaultMessage() you reach the endpoint of Helidon quickstart.