A POC for HTTP/2 with Pippo

Http2Application.java

/*
 * Copyright (C) 2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package ro.pippo.demo.http2;

import org.eclipse.jetty.server.PushBuilder;
import org.eclipse.jetty.server.Request;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import ro.pippo.core.Application;
import ro.pippo.core.route.PublicResourceHandler;
import ro.pippo.core.route.RouteContext;
import ro.pippo.core.route.WebjarsResourceHandler;
import ro.pippo.demo.common.ContactService;
import ro.pippo.demo.common.InMemoryContactService;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author Decebal Suiu
 */
public class Http2Application extends Application {

    private ContactService contactService;

    @Override
    protected void onInit() {
        contactService = new InMemoryContactService();

        // add routes for static content
//        addPublicResourceRoute();
        addResourceRoute(new PublicResourceHandler().setVersioned(false)); // disable versioning
//        addWebjarsResourceRoute();
        addResourceRoute(new WebjarsResourceHandler().setVersioned(false)); // disable versioning

        getRouter().ignorePaths("/favicon.ico");

        // send 'Hello World' as response
        GET("/", routeContext -> routeContext.send("Hello World"));

        // send a page created from a template
//        GET("/contacts", this::sendContactsPage);
        GET("/contacts", this::sendContactsPage2);
    }

    /*
     * The "contacts.html" page contains below resources/assets:
     * 
     * - in "head" section
     * <link href="/webjars/bootstrap/css/bootstrap.min.css" rel="stylesheet">
     * <link href="/webjars/font-awesome/css/font-awesome.min.css" rel="stylesheet">
     * <link href="/public/css/style.css" rel="stylesheet">
     *     
     * - in "body" section
     * <script src="/webjars/jquery/jquery.min.js"></script>
     * <script src="/webjars/bootstrap/js/bootstrap.min.js"></script>
     */
    private void sendContactsPage(RouteContext routeContext) {
        // Jetty specific APIs (Jetty 9 is based on Servlet 3.1)
        PushBuilder pushBuilder = Request.getBaseRequest(routeContext.getRequest().getHttpServletRequest()).getPushBuilder();
        getPushResourcePaths().forEach(path -> pushBuilder.path(path).push());

        Map<String, Object> model = new HashMap<>();
        model.put("contacts", contactService.getContacts());
        routeContext.render("contacts", model);
    }

    private void sendContactsPage2(RouteContext routeContext) {
        Map<String, Object> model = new HashMap<>();
        model.put("contacts", contactService.getContacts());
        String html = routeContext.renderToString("contacts", model);

        // Jetty specific APIs (Jetty 9 is based on Servlet 3.1)
        PushBuilder pushBuilder = Request.getBaseRequest(routeContext.getRequest().getHttpServletRequest()).getPushBuilder();
        getPushResourcePaths(html).forEach(path -> pushBuilder.path(path).push());

        routeContext.send(html);
    }

    /*
     * Retrieve manually the resources paths that will be pushed.
     * In this case, the developer must supply this information, for each page.
     */
    private List<String> getPushResourcePaths() {
        List<String> paths = new ArrayList<>();

        paths.add("/webjars/bootstrap/css/bootstrap.min.css");
        paths.add("/webjars/font-awesome/css/font-awesome.min.css");
        paths.add("/public/css/style.css");
        paths.add("/webjars/jquery/jquery.min.js");
        paths.add("/webjars/bootstrap/js/bootstrap.min.js");

        return paths;
    }

    /*
     * Retrieve automatically (parsing the HTML page) the resources paths that will be pushed.
     */
    private List<String> getPushResourcePaths(String html) {
        List<String> paths = new ArrayList<>();

        Document doc = Jsoup.parse(html);
        Elements elements = doc.head().select("link[href]");
        for (Element element : elements) {
            paths.add(element.attr("href"));
        }

        elements = doc.body().select("script[src]");
        for (Element element : elements) {
            paths.add(element.attr("src"));
        }

        return paths;
    }

}