1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.example.http.cors;
17
18 import io.netty.bootstrap.ServerBootstrap;
19 import io.netty.channel.EventLoopGroup;
20 import io.netty.channel.nio.NioEventLoopGroup;
21 import io.netty.channel.socket.nio.NioServerSocketChannel;
22 import io.netty.example.util.ServerUtil;
23 import io.netty.handler.logging.LogLevel;
24 import io.netty.handler.logging.LoggingHandler;
25 import io.netty.handler.ssl.SslContext;
26
27 /**
28 * This example server aims to demonstrate
29 * <a href="https://www.w3.org/TR/cors/">Cross Origin Resource Sharing</a> (CORS) in Netty.
30 * It does not have a client like most of the other examples, but instead has
31 * a html page that is loaded to try out CORS support in a web browser.
32 * <p>
33 *
34 * CORS is configured in {@link HttpCorsServerInitializer} and by updating the config you can
35 * try out various combinations, like using a specific origin instead of a
36 * wildcard origin ('*').
37 * <p>
38 *
39 * The file {@code src/main/resources/cors/cors.html} contains a very basic example client
40 * which can be used to try out different configurations. For example, you can add
41 * custom headers to force a CORS preflight request to make the request fail. Then
42 * to enable a successful request, configure the CorsHandler to allow that/those
43 * request headers.
44 *
45 * <h2>Testing CORS</h2>
46 * You can either load the file {@code src/main/resources/cors/cors.html} using a web server
47 * or load it from the file system using a web browser.
48 *
49 * <h3>Using a web server</h3>
50 * To test CORS support you can serve the file {@code src/main/resources/cors/cors.html}
51 * using a web server. You can then add a new host name to your systems hosts file, for
52 * example if you are on Linux you may update /etc/hosts to add an additional name
53 * for you local system:
54 * <pre>
55 * 127.0.0.1 localhost domain1.com
56 * </pre>
57 * Now, you should be able to access {@code http://domain1.com/cors.html} depending on how you
58 * have configured you local web server the exact url may differ.
59 *
60 * <h3>Using a web browser</h3>
61 * Open the file {@code src/main/resources/cors/cors.html} in a web browser. You should see
62 * loaded page and in the text area the following message:
63 * <pre>
64 * 'CORS is not working'
65 * </pre>
66 *
67 * If you inspect the headers being sent using your browser you'll see that the 'Origin'
68 * request header is {@code 'null'}. This is expected and happens when you load a file from the
69 * local file system. Netty can handle this by configuring the CorsHandler which is done
70 * in the {@link HttpCorsServerInitializer}.
71 *
72 */
73 public final class HttpCorsServer {
74
75 static final boolean SSL = System.getProperty("ssl") != null;
76 static final int PORT = Integer.parseInt(System.getProperty("port", SSL? "8443" : "8080"));
77
78 public static void main(String[] args) throws Exception {
79 // Configure SSL.
80 final SslContext sslCtx = ServerUtil.buildSslContext();
81
82 EventLoopGroup bossGroup = new NioEventLoopGroup(1);
83 EventLoopGroup workerGroup = new NioEventLoopGroup();
84 try {
85 ServerBootstrap b = new ServerBootstrap();
86 b.group(bossGroup, workerGroup)
87 .channel(NioServerSocketChannel.class)
88 .handler(new LoggingHandler(LogLevel.INFO))
89 .childHandler(new HttpCorsServerInitializer(sslCtx));
90
91 b.bind(PORT).sync().channel().closeFuture().sync();
92 } finally {
93 bossGroup.shutdownGracefully();
94 workerGroup.shutdownGracefully();
95 }
96 }
97 }