GreetingResource

GreetingResource.java

import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeUnit;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;

import org.eclipse.microprofile.config.inject.ConfigProperty;

@Path("/hello")
public class GreetingResource {

    @ConfigProperty(name = "my.knative.service")
    URI service;

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response hello() {
        return Response.accepted(doPost(service)).status(javax.ws.rs.core.Response.Status.OK).build();
    }

    private String doPost(URI uri) {
        if (null == uri) {
            throw new RuntimeException("URI is null");
        }
        OkHttpClient okClient = new OkHttpClient.Builder()
                .connectTimeout(15, TimeUnit.SECONDS)
                .writeTimeout(15, TimeUnit.SECONDS)
                .readTimeout(60, TimeUnit.SECONDS)
                .build();

        StringBuilder url = new StringBuilder(uri.getScheme())
                .append("://")
                .append(uri.getHost());

        if (uri.getPort() != -1) {
            url.append(":");
            url.append(uri.getPort());
        }

        String payload = "{\"workflowdata\" : {\"name\": \"John\", \"language\": \"Spanish\"}}";
        url.append("/jsongreet");

        System.out.println("Calling url -- " + url + " with payload -> " + payload);
        Request request = new Request.Builder()
                .url(url.toString())
                .addHeader("charset", StandardCharsets.UTF_8.name())
                .post(RequestBody.create(okhttp3.MediaType.parse("application/json; charset=utf-8"), payload))
                .build();

        try (okhttp3.Response response = okClient.newCall(request).execute()) {
            return response.body().string();
        } catch (final Exception e) {
            e.printStackTrace();
        }
        return "no response body to return";
    }
}