Netty实现简单WebSocket服务器

本文参考《Netty权威指南》
├── WebSocketServerHandler.java
├── WebSocketServer.java
└── wsclient.html

package com.xh.netty.test11;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
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.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.stream.ChunkedWriteHandler;

/**
 * Created by root on 1/8/18.
 */
public class WebSocketServer {
    public void run(int port) {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            ChannelPipeline pipeline = socketChannel.pipeline();
                            pipeline.addLast("http-codec", new HttpServerCodec());
                            pipeline.addLast("aggregator", new HttpObjectAggregator(65536));
                            pipeline.addLast("http-chunked", new ChunkedWriteHandler());
                            pipeline.addLast("handler", new WebSocketServerHandler());
                        }
                    });
            Channel ch = b.bind(port).sync().channel();
            System.out.println("websocketserver start port at " + port);
            ch.closeFuture().sync();

        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        int port = 8080;
        if (args.length > 0) {
            port = Integer.valueOf(args[0]);

        }
        new WebSocketServer().run(port);

    }
}

package com.xh.netty.test11;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.util.CharsetUtil;

import java.util.Date;
import java.util.logging.Logger;

import static io.netty.handler.codec.http.HttpHeaderUtil.isKeepAlive;
import static io.netty.handler.codec.http.HttpHeaderUtil.setContentLength;

/**
 * Created by root on 1/8/18.
 */
public class WebSocketServerHandler extends SimpleChannelInboundHandler {
    private WebSocketServerHandshaker handshaker;

    @Override
    protected void messageReceived(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println(msg.toString());
        //http
        if (msg instanceof FullHttpRequest) {
            handleHttpRequest(ctx, (FullHttpRequest) msg);
        } else if (msg instanceof WebSocketFrame) {//websocket
            handleWebsocketFrame(ctx, (WebSocketFrame) msg);
        }
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }

    private void handleWebsocketFrame(ChannelHandlerContext ctx, WebSocketFrame msg) {
        //关闭链路指令
        if (msg instanceof CloseWebSocketFrame) {
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) msg.retain());
            return;
        }

        //PING 消息
        if (msg instanceof PingWebSocketFrame) {
            ctx.write(new PongWebSocketFrame(msg.content().retain()));
            return;
        }

        //非文本
        if (!(msg instanceof TextWebSocketFrame)) {
            throw new UnsupportedOperationException(String.format("%s frame type not support", msg.getClass().getName()));

        }

        //应答消息
        String requset = ((TextWebSocketFrame) msg).text();
        ctx.channel().write(new TextWebSocketFrame(requset + " >>>>Now is " + new Date().toString()));

    }

    private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest msg) {

        //HTTP 请异常
        if (!msg.decoderResult().isSuccess() || !"websocket".equals(msg.headers().get("Upgrade"))) {
            System.out.println(msg.decoderResult().isSuccess());
            System.out.println(msg.headers().get("Upgrade"));
            sendHttpResponse(ctx, msg, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST));
            return;
        }

        //握手
        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory("ws://localhost:8080/websocket", null, false);
        handshaker = wsFactory.newHandshaker(msg);
        if (handshaker == null) {
            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());

        } else {
            handshaker.handshake(ctx.channel(), msg);
        }
    }

    private void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest msg, FullHttpResponse resp) {

        //响应
        if (resp.status().code() != 200) {
            ByteBuf buf = Unpooled.copiedBuffer(resp.status().toString(), CharsetUtil.UTF_8);
            resp.content().writeBytes(buf);
            buf.release();
            setContentLength(resp, resp.content().readableBytes());
        }

        //非Keep-Alive,关闭链接
        ChannelFuture future = ctx.channel().writeAndFlush(resp);
        if (!isKeepAlive(resp) || resp.status().code() != 200) {
            future.addListener(ChannelFutureListener.CLOSE);
        }

    }

}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form onsubmit="return false;">
    <input type="text" name="msg" value="NETTY">
    <button onclick="send(this.form.msg.value)">send</button>
    <br>
    <textarea id="resText">

    </textarea>

</form>
</body>
<script>
    var socket;
    if (!window.WebSocket) {
        window.WebSocket = window.MozWebSocket;
    }
    if (window.WebSocket) {
        socket = new WebSocket("ws://127.0.0.1:8080/websocket");
        socket.onmessage = function (event) {
            var ta = document.getElementById("resText");
            ta.value = "";
            ta.value = event.data;

        };

        socket.onopen = function (event) {
            alert("浏览器支持WebSocket");
            var ta = document.getElementById("resText");
            ta.value = "";
            ta.value = "浏览器支持WebSocket";
        };

        socket.onclose = function (event) {
            var ta = document.getElementById("resText");
            ta.value = "";
            ta.value = "关闭WebSocket";
        }
    } else {

        alert("浏览器不支持WebSocket");
    }

    function send(msg) {
        if (!window.WebSocket) {
            return;

        }
        if (socket.readyState == WebSocket.OPEN) {
            socket.send(msg);
        } else {
            alert("建立连接失败")
        }
    }
</script>
</html>