PushServlet.java
/*
* JBoss, Home of Professional Open Source.
* Copyright 2021 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* 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 io.undertow.servlet.test.push;
import java.io.IOException;
import java.util.Base64;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.PushBuilder;
/**
* <p>Simple servlet that pushes resources for index.html and *.css. The idea
* is that double promises are not sent as they are forbidden by the spec.</p>
*
* @author rmartinc
*/
public class PushServlet extends HttpServlet {
// A simple blue pixel in PNG format
private static final String PNG_BASE64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==";
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
if (request.getServletPath().endsWith(".html") || request.getPathInfo().endsWith(".html")) {
PushBuilder pushBuilder = request.newPushBuilder();
if (pushBuilder != null) {
// pushing css and js in advance
pushBuilder.path("resources/one.css").push();
pushBuilder.path("resources/one.js").push();
}
try (ServletOutputStream out = response.getOutputStream()) {
out.println("<html>");
out.println(" <head>");
out.println(" <link type=\"text/css\" rel=\"stylesheet\" href=\"resources/one.css\" />");
out.println(" <script type=\"text/javascript\" src=\"resources/one.js\"></script>");
out.println(" </head>");
out.println(" <body>");
out.println(" <span class=\"border\">PUSH PROMISES</span>");
out.println(" </body>");
out.println("</html>");
}
} else if (request.getPathInfo().endsWith(".css")) {
PushBuilder pushBuilder = request.newPushBuilder();
if (pushBuilder != null) {
// pushing images in advance
pushBuilder.path("resources/one.png").push();
}
response.setContentType("text/css");
try (ServletOutputStream out = response.getOutputStream()) {
out.println("body, html {");
out.println(" height: 100%;");
out.println(" margin: 0;");
out.println(" background-image: url(\"one.png\");");
out.println(" background-repeat: repeat;");
out.println("}");
}
} else if (request.getPathInfo().endsWith(".js")) {
response.setContentType("application/javascript");
try (ServletOutputStream out = response.getOutputStream()) {
out.println("console.log('loading js file ' + location.pathname);");
}
} else if (request.getPathInfo().endsWith(".png")) {
byte[] bytes = Base64.getDecoder().decode(PNG_BASE64);
response.setContentType("image/png");
try (ServletOutputStream out = response.getOutputStream()) {
out.write(bytes);
}
} else {
throw new ServletException("Invalid request");
}
}
}