.NET Core3.1 Dotnetty实战第一章

// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

namespace Echo.Server
{
    using System;
    using System.Text;
    using DotNetty.Buffers;
    using DotNetty.Transport.Channels;

    /// <summary>
    /// 该类为Server的Channel具体、定义实现
    /// </summary>
    public class EchoServerHandler : ChannelHandlerAdapter
    {
        /*
         * Channel的生命周期
         * 1.ChannelRegistered 先注册
         * 2.ChannelActive 再被激活
         * 3.ChannelRead 客户端与服务端建立连接之后的会话（数据交互）
         * 4.ChannelReadComplete 读取客户端发送的消息完成之后
         * error. ExceptionCaught 如果在会话过程当中出现dotnetty框架内部异常都会通过Caught方法返回给开发者
         * 5.ChannelInactive 使当前频道处于未激活状态
         * 6.ChannelUnregistered 取消注册
         */

        /// <summary>
        /// 频道注册
        /// </summary>
        /// <param name="context"></param>
        public override void ChannelRegistered(IChannelHandlerContext context)
        {
            base.ChannelRegistered(context);
        }

        /// <summary>
        /// socket client 连接到服务端的时候channel被激活的回调函数
        /// </summary>
        /// <param name="context"></param>
        public override void ChannelActive(IChannelHandlerContext context)
        {
            //一般可用来记录连接对象信息
            base.ChannelActive(context);
        }

        /// <summary>
        /// socket接收消息方法具体的实现
        /// </summary>
        /// <param name="context">当前频道的句柄，可使用发送和接收方法</param>
        /// <param name="message">接收到的客户端发送的内容</param>
        public override void ChannelRead(IChannelHandlerContext context, object message)
        {
            var buffer = message as IByteBuffer;
            if (buffer != null)
            {
                Console.WriteLine("Received from client: " + buffer.ToString(Encoding.UTF8));
            }
            context.WriteAsync(message);//这里官方的例子是直接讲客户端发送的内容原样返回给客户端，WriteAsync（）是讲要发送的内容写入到数据流的缓存中。如果不想进入数据流可以直接调用WirteAndFlusAsync（）写好了直接发送
        }

        /// <summary>
        /// 该次会话读取完成后回调函数
        /// </summary>
        /// <param name="context"></param>
        public override void ChannelReadComplete(IChannelHandlerContext context) => context.Flush();//将WriteAsync写入的数据流缓存发送出去

        /// <summary>
        /// 异常捕获
        /// </summary>
        /// <param name="context"></param>
        /// <param name="exception"></param>
        public override void ExceptionCaught(IChannelHandlerContext context, Exception exception)
        {
            Console.WriteLine("Exception: " + exception);
            context.CloseAsync();
        }

        /// <summary>
        /// 当前频道未激活状态
        /// </summary>
        /// <param name="context"></param>
        public override void ChannelInactive(IChannelHandlerContext context)
        {
            base.ChannelInactive(context);
        }

        /// <summary>
        /// 取消注册当前频道，可理解为销毁当前频道
        /// </summary>
        /// <param name="context"></param>
        public override void ChannelUnregistered(IChannelHandlerContext context)
        {
            base.ChannelUnregistered(context);
        }
    }
}

// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

namespace Echo.Client
{
    using System;
    using System.IO;
    using System.Net;
    using System.Net.Security;
    using System.Security.Cryptography.X509Certificates;
    using System.Threading.Tasks;
    using DotNetty.Codecs;
    using DotNetty.Handlers.Logging;
    using DotNetty.Handlers.Tls;
    using DotNetty.Transport.Bootstrapping;
    using DotNetty.Transport.Channels;
    using DotNetty.Transport.Channels.Sockets;
    using Examples.Common;

    class Program
    {
        static async Task RunClientAsync()
        {
            ExampleHelper.SetConsoleLogger();

            var group = new MultithreadEventLoopGroup();//客户端与服务端不同的是，只需要一个主工作组进行工作协调即可不需要创建子线程组

            X509Certificate2 cert = null;
            string targetHost = null;
            if (ClientSettings.IsSsl)
            {
                cert = new X509Certificate2(Path.Combine(ExampleHelper.ProcessDirectory, "dotnetty.com.pfx"), "password");
                targetHost = cert.GetNameInfo(X509NameType.DnsName, false);
            }
            try
            {
                var bootstrap = new Bootstrap();
                bootstrap
                    .Group(group)
                    .Channel<TcpSocketChannel>()
                    .Option(ChannelOption.TcpNodelay, true)//设置为true的话不允许延迟直接发出，因为dotnetty内部实现中会将消息积累到一定的字节之后才发出。
                    .Handler(new ActionChannelInitializer<ISocketChannel>(channel =>
                    {
                        IChannelPipeline pipeline = channel.Pipeline;

                        if (cert != null)
                        {
                            pipeline.AddLast("tls", new TlsHandler(stream => new SslStream(stream, true, (sender, certificate, chain, errors) => true), new ClientTlsSettings(targetHost)));
                        }
                        pipeline.AddLast(new LoggingHandler());//donetty框架内部日志
                        pipeline.AddLast("framing-enc", new LengthFieldPrepender(2));
                        pipeline.AddLast("framing-dec", new LengthFieldBasedFrameDecoder(ushort.MaxValue, 0, 2, 0, 2));

                        pipeline.AddLast("echo", new EchoClientHandler());//client的channel的处理类实现
                    }));

                IChannel clientChannel = await bootstrap.ConnectAsync(new IPEndPoint(ClientSettings.Host, ClientSettings.Port));//设置服务端的端口号和ip地址

                Console.ReadLine();

                await clientChannel.CloseAsync();
            }
            finally
            {
                await group.ShutdownGracefullyAsync(TimeSpan.FromMilliseconds(100), TimeSpan.FromSeconds(1));
            }
        }

        static void Main() => RunClientAsync().Wait();
    }
}