netty 实现https服务器

0 概述

netty 通过JDK的SSLEngine，以SslHandler的方式提供对SSL/TLS 安全传输的支持，极大的简化了开发工作。本文主要讲述如何使用netty实现简单的https服务器。

1 SSL单向认证

所谓的单向认证，即客户端只验证服务端的合法性，服务端不会验证客户端。
单向认证过程的总结如下：
1.SSL客户端（浏览器）向服务端传送客户端 SSL协议的版本号、支持的加密算法种类、产生的随机数，以及其他可选信息。
2.服务端返回握手应答，向客户端传送确认SSL协议的版本号、加密算法种类、随机数以及其他信息。
3.服务端向客户端发送自己的证书，这个证书其实就是公钥，只是包含了很多信息，如证书的颁发机构，过期时间等等
4.客户端对服务端的证书进行认证，服务端的合法性校验包括：证书是否过期、发行服务器证书CA是否可靠、发行者证书的公钥能否解开服务器证书的“发行者数字签名”等
5.客户端随机产生一个用于后续通信的对称密钥，然后用服务端的公钥加密传输给服务端，通知服务端客户端的握手结束。
6.服务端解密获取客户端的对称密钥，同时通知客户端服务端的握手结束。
7.SSL的握手部分结束，SSL安全通道建立，客户端和服务端开始使用相同的对称密钥对数据进行加密，然后通过socket进行传输。

2 具体实现

利用JDK的keytool 工具，生成服务端私钥和证书仓库。
执行如下命令：
keytool -genkey -keysize 2048 -validity 365 -keyalg RSA -dname “CN=localhost” -keypass hsc123 -storepass hsc123 -keystore local.jks

import io.netty.bootstrap.ServerBootstrap;import io.netty.channel.ChannelFuture;import io.netty.channel.ChannelInitializer;import io.netty.channel.ChannelOption;import io.netty.channel.EventLoopGroup;import io.netty.channel.nio.NioEventLoopGroup;import io.netty.channel.socket.SocketChannel;import io.netty.channel.socket.nio.NioServerSocketChannel;import io.netty.handler.codec.http.HttpServerCodec;import io.netty.handler.ssl.SslHandler;import javax.net.ssl.SSLContext;import javax.net.ssl.SSLEngine;/** * Created by apple on 17/10/21. */public class HttpsServer {    public static void start(final int port) throws Exception {        EventLoopGroup boss = new NioEventLoopGroup();        EventLoopGroup worker = new NioEventLoopGroup();        ServerBootstrap serverBootstrap = new ServerBootstrap();        try {            serverBootstrap.channel(NioServerSocketChannel.class)                    .option(ChannelOption.SO_BACKLOG, 1024)                    .group(boss, worker)                    .childHandler(new ChannelInitializer<SocketChannel>() {                        @Override                        protected void initChannel(SocketChannel ch) throws Exception {                            SSLEngine sslEngine = SSLContextFactory.getSslContext().createSSLEngine();                            sslEngine.setUseClientMode(false);                            ch.pipeline().addLast(new SslHandler(sslEngine));                            ch.pipeline().addLast("http-decoder", new HttpServerCodec());                            ch.pipeline().addLast(new HttpsSeverHandler());                        }                    });            ChannelFuture future = serverBootstrap.bind(port).sync();            future.channel().closeFuture().sync();        } finally {            boss.shutdownGracefully();            worker.shutdownGracefully();        }    }    public static void main(String[] args) throws Exception {        start(7000);    }}

import javax.net.ssl.KeyManagerFactory;import javax.net.ssl.SSLContext;import java.io.FileInputStream;import java.security.KeyStore;import java.security.KeyStoreException;/** * Created by apple on 17/10/21. */public class SSLContextFactory {    public static SSLContext getSslContext() throws Exception {        char[] passArray = "hsc123".toCharArray();        SSLContext sslContext = SSLContext.getInstance("TLSv1");        KeyStore ks = KeyStore.getInstance("JKS");        //加载keytool 生成的文件        FileInputStream inputStream = new FileInputStream("/Users/apple/local.jks");        ks.load(inputStream, passArray);        KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());        kmf.init(ks, passArray);        sslContext.init(kmf.getKeyManagers(), null, null);        inputStream.close();        return sslContext;    }

import io.netty.channel.ChannelFutureListener;import io.netty.channel.ChannelHandlerContext;import io.netty.channel.ChannelInboundHandlerAdapter;import io.netty.handler.codec.http.*;/** * Created by apple on 17/10/21. */public class HttpsSeverHandler extends ChannelInboundHandlerAdapter {    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {        if (msg instanceof HttpRequest) {            HttpRequest request = (HttpRequest) msg;            boolean keepaLive = HttpUtil.isKeepAlive(request);            System.out.println("method" + request.method());            System.out.println("uri" + request.uri());            FullHttpResponse httpResponse = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);            httpResponse.content().writeBytes("https".getBytes());            httpResponse.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html;charset=UTF-8");            httpResponse.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, httpResponse.content().readableBytes());            if (keepaLive) {                httpResponse.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);                ctx.writeAndFlush(httpResponse);            } else {                ctx.writeAndFlush(httpResponse).addListener(ChannelFutureListener.CLOSE);            }        }    }}

3 测试

启动服务 输入https://127.0.0.1:7000

参考文献
[1] Netty 权威指南（第二版），李林峰著