Registering Thymeleaf Templateengine in Jersey

Question

I'm trying to combine the Thymeleaf template engine with a Jersey REST Server.

I already found this example of a ThymeleafViewProcessor (https://github.com/bufferings/jersey-thymeleaf) but I don't understand how to bind the processor to the jersey server.

@Provider
public class ThymeleafViewProcessor implements ViewProcessor<String> {
  @Context
  ServletContext servletContext;

  @Context
  ThreadLocal<HttpServletRequest> requestInvoker;

  @Context
  ThreadLocal<HttpServletResponse> responseInvoker;

  TemplateEngine templateEngine;

  public ThymeleafViewProcessor() {
    TemplateResolver templateResolver = new ServletContextTemplateResolver();
    templateResolver.setPrefix("/WEB-INF/templates/");
    templateResolver.setSuffix(".html");
    templateResolver.setTemplateMode("HTML5");
    templateResolver.setCacheTTLMs(3600000L);

    templateEngine = new TemplateEngine();
    templateEngine.setTemplateResolver(templateResolver);
  }

  @Override
  public String resolve(final String path) {
    return path;
  }

  @Override
  public void writeTo(final String resolvedPath, final Viewable viewable,
      final OutputStream out) throws IOException {
    // Commit the status and headers to the HttpServletResponse
    out.flush();

    WebContext context = new WebContext(requestInvoker.get(),
        responseInvoker.get(), servletContext, requestInvoker.get().getLocale());
    Map<String, Object> variables = new HashMap<>();
    variables.put("it", viewable.getModel());
    context.setVariables(variables);
    templateEngine.process(viewable.getTemplateName(), context, responseInvoker
        .get().getWriter());
  }

Here is my start up class:

public class App {

  /**
   * Starts the lightweight HTTP server serving the JAX-RS application.
   *
   * @return new instance of the lightweight HTTP server
   * @throws IOException
   */
  static HttpServer startServer() throws IOException {
    // create a new server listening at port 8080
    HttpServer server = HttpServer.create(new InetSocketAddress(getBaseURI().getPort()), 0);

    // create a handler wrapping the JAX-RS application
    HttpHandler handler = RuntimeDelegate.getInstance().createEndpoint(new JaxRsApplication(), HttpHandler.class);

    // map JAX-RS handler to the server root
    server.createContext(getBaseURI().getPath(), handler);

    // start the server
    server.start();

    return server;
  }

  @SuppressWarnings("ResultOfMethodCallIgnored")
  public static void main(String[] args) throws IOException {
    System.out.println("\"Hello World\" Jersey Example Application");

    HttpServer server = startServer();

    System.out.println("Application started.\n"
        + "Try accessing " + getBaseURI() + "hello in the browser.\n"
        + "Hit enter to stop the application...");
    System.in.read();
    server.stop(0);
  }

  private static int getPort(int defaultPort) {
    final String port = System.getProperty("jersey.config.test.container.port");
    if (null != port) {
      try {
        return Integer.parseInt(port);
      } catch (NumberFormatException e) {
        System.out.println("Value of jersey.config.test.container.port property"
            + " is not a valid positive integer [" + port + "]."
            + " Reverting to default [" + defaultPort + "].");
      }
    }
    return defaultPort;
  }

  /**
   * Gets base {@link URI}.
   *
   * @return base {@link URI}.
   */
  public static URI getBaseURI() {
    return UriBuilder.fromUri("http://localhost/").port(getPort(8080)).build();
  }
}

HelloResource:

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

  @GET
  @Path("/{n}")
  @Produces(MediaType.TEXT_HTML)
  public Viewable sayHello(@PathParam("n") String name) {
    return new Viewable("sample", "Hello " + name + "!");
  }

  @GET
  @Produces(MediaType.TEXT_HTML)
  public Viewable sayHello() {
    return new Viewable("sample",
        new SampleModel("Good morning", "my friends"));
  }

  public static class SampleModel {
    public String greeting;
    public String name;

    public SampleModel(String greeting, String name) {
      this.greeting = greeting;
      this.name = name;
    }
  }
}

What do I have to do now to bind the ViewProcessor to Jersey. I don't find any examples in the web and other solutions (freemarker) seem to work differently.

Answer 1

I solved it by binding the view processor as eager singleton:

public class TemplateModule extends AbstractModule {
    @Override
    protected void configure() {
        // bind thymeleaf processor as eager singleton
        bind(ThymeleafViewProcessor.class).asEagerSingleton();
    }
}

Then add it to your injector. This should work.