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基于netty的websocket服务

2017-08-21 21:59 357 查看
我们下面则将一些实际场景都添加进去,比如用户身份的验证,游客只能浏览不能发言,多房间(频道)的聊天。
该博客非常适合 Java 新手,非常适合作为学习 Java 的切入点,不需要考虑tomcat、spring、mybatis等。
唯一的知识点就是 maven 的基础使用。

├── WebSocketServer.java                启动服务器端口监听

├── WebSocketServerInitializer.java     初始化服务

├── WebSocketServerHandler.java         接管WebSocket数据连接

├── dto

│   └── Response.java                   返回给客户端数据对象

├── entity

│   └── Client.java                     每个连接到WebSocket服务的客户端对象

└── service

    ├── MessageService.java             完成发送消息

    └── RequestService.java             WebSocket初始化连接握手时的数据处理


功能设计概述


身份认证

客户端将用户 id 、进入的房间的 rid、用户 token 
json_encode
,例如
{id:1;rid:21;token:'43606811c7305ccc6abb2be116579bfd'}
。然后在 
base64
 处理,通过参数
request
传到服务器,然后在服务器做
id 和 token 的验证(我的做法是 token 存放在redis string 5秒的过期时间)


房间表

使用一个Map 
channelGroupMap
 来存放各个房间(频道),以客户端传握手时传过来的 base64 字符串中获取到定义的房间
ID,然后为该房间 ID 新建一个
ChannelGroup
ChannelGroup
 方便对该组内的所有客户端广播消息)


在 pom.xml 中引入netty 5

<dependencies>
<dependency>
<groupId>io.netty</groupId>
<artifactId>netty-all</artifactId>
<version>5.0.0.Alpha2</version>
</dependency>
<dependency>
<groupId>com.jcraft</groupId>
<artifactId>jzlib</artifactId>
<version>1.1.2</version>
</dependency>
<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20141113</version>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.10</version>
</dependency>
</dependencies>


创建服务器

这段代码需要理解吗?这是 netty 的套路,可以先记住 netty 的线程模型是一个 react 的一种变型,这里有两个nio线程组,一个是接受客户端的请求,一个是worker组专门处理客户端的请求。

可以简单的理解下面的代码就构建了一个nginx服务器。所以不用管。
package net.mengkang;

import io.netty.bootstrap.ServerBootstrap;

import io.netty.channel.Channel;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.nio.NioServerSocketChannel;

import io.netty.handler.logging.LogLevel;

import io.netty.handler.logging.LoggingHandler;

public final class WebSocketServer {

    private static final int PORT = 8083;

    public static void main(String[] args) throws Exception {

        EventLoopGroup bossGroup = new NioEventLoopGroup(1);

        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {

            ServerBootstrap b = new ServerBootstrap();

            b.group(bossGroup, workerGroup)

                    .channel(NioServerSocketChannel.class)

                    .handler(new LoggingHandler(LogLevel.INFO))

                    .childHandler(new WebSocketServerInitializer());

            Channel ch = b.bind(PORT).sync().channel();

            ch.closeFuture().sync();

        } finally {

            bossGroup.shutdownGracefully();

            workerGroup.shutdownGracefully();

        }

    }

}

package net.mengkang;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.ChannelPipeline;

import io.netty.channel.socket.SocketChannel;

import io.netty.handler.codec.http.HttpObjectAggregator;

import io.netty.handler.codec.http.HttpServerCodec;

import io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler;

public class WebSocketServerInitializer extends ChannelInitializer<SocketChannel> {

    @Override

    public void initChannel(SocketChannel ch) throws Exception {

        ChannelPipeline pipeline = ch.pipeline();

        pipeline.addLast(new HttpServerCodec());

        pipeline.addLast(new HttpObjectAggregator(65536));

        pipeline.addLast(new WebSocketServerCompressionHandler());

        pipeline.addLast(new WebSocketServerHandler());

    }

}


处理长连接

下面程序中最的处理在握手阶段
handleHttpRequest
,里面处理参数的判断,用户的认证,登录用户表的维护,直播房间表维护。详细的请大家对照代码来浏览。

握手完成之后的消息传递则在
handleWebSocketFrame
中处理。

整理的执行流程,大家可以对各个方法打断点予以调试,就会很清楚整个执行的脉络啦。

package net.mengkang;

import io.netty.buffer.ByteBuf;

import io.netty.buffer.Unpooled;

import io.netty.channel.*;

import io.netty.channel.group.ChannelGroup;

import io.netty.channel.group.DefaultChannelGroup;

import io.netty.handler.codec.http.*;

import io.netty.handler.codec.http.websocketx.*;

import io.netty.util.CharsetUtil;

import io.netty.util.concurrent.GlobalEventExecutor;

import net.mengkang.dto.Response;

import net.mengkang.entity.Client;

import net.mengkang.service.MessageService;

import net.mengkang.service.RequestService;

import org.json.JSONObject;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import static io.netty.handler.codec.http.HttpHeaderNames.HOST;

import static io.netty.handler.codec.http.HttpMethod.GET;

import static io.netty.handler.codec.http.HttpResponseStatus.*;

import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;

public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> {

    // websocket 服务的 uri

    private static final String WEBSOCKET_PATH = "/websocket";

    // 一个 ChannelGroup 代表一个直播频道

    private static Map<Integer, ChannelGroup> channelGroupMap = new ConcurrentHashMap <>();

    // 本次请求的 code

    private static final String HTTP_REQUEST_STRING = "request";

    private Client client = null;

    private WebSocketServerHandshaker handshaker;

    @Override

    public void messageReceived(ChannelHandlerContext ctx, Object msg) {

        if (msg instanceof FullHttpRequest) {

            handleHttpRequest(ctx, (FullHttpRequest) msg);

        } else if (msg instanceof WebSocketFrame) {

            handleWebSocketFrame(ctx, (WebSocketFrame) msg);

        }

    }

    @Override

    public void channelReadComplete(ChannelHandlerContext ctx) {

        ctx.flush();

    }

    private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) {

        // Handle a bad request.

        if (!req.decoderResult().isSuccess()) {

            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST));

            return;

        }

        // Allow only GET methods.

        if (req.method() != GET) {

            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN));

            return;

        }

        if ("/favicon.ico".equals(req.uri()) || ("/".equals(req.uri()))) {

            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND));

            return;

        }

        QueryStringDecoder queryStringDecoder = new QueryStringDecoder(req.uri());

        Map<String, List<String>> parameters = queryStringDecoder.parameters();

        if (parameters.size() == 0 || !parameters.containsKey(HTTP_REQUEST_STRING)) {

            System.err.printf(HTTP_REQUEST_STRING + "参数不可缺省");

            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND));

            return;

        }

        client = RequestService.clientRegister(parameters.get(HTTP_REQUEST_STRING).get(0));

        if (client.getRoomId() == 0) {

            System.err.printf("房间号不可缺省");

            sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND));

            return;

        }

        // 房间列表中如果不存在则为该频道,则新增一个频道 ChannelGroup

        if (!channelGroupMap.containsKey(client.getRoomId())) {

            channelGroupMap.put(client.getRoomId(), new DefaultChannelGroup(GlobalEventExecutor.INSTANCE));

        }

        // 确定有房间号,才将客户端加入到频道中

        channelGroupMap.get(client.getRoomId()).add(ctx.channel());

        // Handshake

        WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(getWebSocketLocation(req), null, true);

        handshaker = wsFactory.newHandshaker(req);

        if (handshaker == null) {

            WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel());

        } else {

            ChannelFuture channelFuture = handshaker.handshake(ctx.channel(), req);

            // 握手成功之后,业务逻辑

            if (channelFuture.isSuccess()) {

                if (client.getId() == 0) {

                    System.out.println(ctx.channel() + " 游客");

                    return;

                }

            }

        }

    }

    private void broadcast(ChannelHandlerContext ctx, WebSocketFrame frame) {

        if (client.getId() == 0) {

            Response response = new Response(1001, "没登录不能聊天哦");

            String msg = new JSONObject(response).toString();

            ctx.channel().write(new TextWebSocketFrame(msg));

            return;

        }

        String request = ((TextWebSocketFrame) frame).text();

        System.out.println(" 收到 " + ctx.channel() + request);

        Response response = MessageService.sendMessage(client, request);

        String msg = new JSONObject(response).toString();

        if (channelGroupMap.containsKey(client.getRoomId())) {

            channelGroupMap.get(client.getRoomId()).writeAndFlush(new TextWebSocketFrame(msg));

        }

    }

    private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) {

        if (frame instanceof CloseWebSocketFrame) {

            handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain());

            return;

        }

        if (frame instanceof PingWebSocketFrame) {

            ctx.channel().write(new PongWebSocketFrame(frame.content().retain()));

            return;

        }

        if (!(frame instanceof TextWebSocketFrame)) {

            throw new UnsupportedOperationException(String.format("%s frame types not supported", frame.getClass().getName()));

        }

        broadcast(ctx, frame);

    }

    private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) {

        if (res.status().code() != 200) {

            ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(), CharsetUtil.UTF_8);

            res.content().writeBytes(buf);

            buf.release();

            HttpHeaderUtil.setContentLength(res, res.content().readableBytes());

        }

        ChannelFuture f = ctx.channel().writeAndFlush(res);

        if (!HttpHeaderUtil.isKeepAlive(req) || res.status().code() != 200) {

            f.addListener(ChannelFutureListener.CLOSE);

        }

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {

        cause.printStackTrace();

        ctx.close();

    }

    @Override

    public void handlerAdded(ChannelHandlerContext ctx) throws Exception {

        Channel incoming = ctx.channel();

        System.out.println("收到" + incoming.remoteAddress() + " 握手请求");

    }

    @Override

    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {

        if (client != null && channelGroupMap.containsKey(client.getRoomId())) {

            channelGroupMap.get(client.getRoomId()).remove(ctx.channel());

        }

    }

    private static String getWebSocketLocation(FullHttpRequest req) {

        String location = req.headers().get(HOST) + WEBSOCKET_PATH;

        return "ws://" + location;

    }

}

服务器端就写完啦,还有一些客户端对象的构想验证什么的就不一一细说了,都很简单,都在代码里。下面是客户端。

<html>

<head><title></title></head>

<body>

<script type="text/javascript">

var socket;

if (!window.WebSocket) {

  window.WebSocket = window.MozWebSocket;

}

if (window.WebSocket) {

  socket = new WebSocket("ws://localhost:8083/websocket/?request=e2lkOjE7cmlkOjI2O3Rva2VuOiI0MzYwNjgxMWM3MzA1Y2NjNmFiYjJiZTExNjU3OWJmZCJ9");

  socket.onmessage = function(event) {

      console.log(event.data);

  };

  socket.onopen = function(event) {

    console.log("websocket 打开了");

  };

  socket.onclose = function(event) {

    console.log("websocket 关闭了");

  };

}

function send(message) {

  if (!window.WebSocket) { return; }

  if (socket.readyState == WebSocket.OPEN) {

    socket.send(message);

  } else {

    alert("The socket is not open.");

  }

}

</script>

<form onsubmit="return false;">

  <input type="text" name="message" value="Hello, World!"/>

  <input type="button" value="Send Web Socket Data" onclick="send(this.form.message.value)" />

</form>

</body>

</html>
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