DotNetty系列四：自定义协议，序列化类库MessagePack

在上一节基础上，实现自定义协议，使用MessagePack序列化。

1上引入：Nuget:  MessagePack，MessagePackAnalyzer

2..在类库项目，新建一个枚举（标识命令），一个消息接口，一个消息实现。

    public enum COMMAND{/// <summary>/// 心跳/// </summary>HeartBeat = 1000,/// <summary>/// 消息/// </summary>Message = 1,/// <summary>/// 上线通知/// </summary>OnlineNotify = 1001,/// <summary>/// 下线通知/// </summary>OfflineNotify = 1002,/// <summary>/// 空消息/// </summary>NULL = 0,}public interface IMessage{COMMAND Command { set; get; }string Content { get; set; }}[MessagePackObject] //messagepack必须public class Message : IMessage{[Key(0)]//排序public COMMAND Command { get; set; }[Key(1)]public string Content { get; set; }}

3.新建一个MessagePack序列化操作类。

public static class MessagePackHelper{public static byte[] SerializeToBinary<T>(T obj) => MessagePackSerializer.Serialize(obj);public static T DeserializeWithBinary<T>(byte[] data) => MessagePackSerializer.Deserialize<T>(data);public static string DeserializeJson(byte[] data) => MessagePackSerializer.ToJson(data);public static string DeserializeJson<T>(T data) => MessagePackSerializer.ToJson(data);public static byte[] SerializeJson(string data) => MessagePackSerializer.FromJson(data);public static T DeserializeToJson<T>(string data) => MessagePackSerializer.Deserialize<T>(SerializeJson(data));}

4.修改编码解码器

编码器：

    public class ServerMessagePackEncoder<T> : MessageToByteEncoder<T>{protected override void Encode(IChannelHandlerContext context, T message, IByteBuffer output){//序列化类byte[] messageBytes = MessagePackHelper.SerializeToBinary(message);IByteBuffer initialMessage = Unpooled.Buffer(messageBytes.Length);initialMessage.WriteBytes(messageBytes);output.WriteBytes(initialMessage);}}public class ClientMessagePackEncoder<T> : MessageToByteEncoder<T>{protected override void Encode(IChannelHandlerContext context, T message, IByteBuffer output){//序列化类byte[] messageBytes = MessagePackHelper.SerializeToBinary(message);IByteBuffer initialMessage = Unpooled.Buffer(messageBytes.Length);initialMessage.WriteBytes(messageBytes);output.WriteBytes(initialMessage);}}

解码器：

    public class CommonServerDecoder : ByteToMessageDecoder{protected override void Decode(IChannelHandlerContext context, IByteBuffer input, List<object> output){byte[] array = new byte[input.ReadableBytes];input.GetBytes(input.ReaderIndex, array, 0, input.ReadableBytes);input.Clear();var temp = MessagePackHelper.DeserializeWithBinary<Message>(array);output.Add(temp);}}public class CommonClientDecoder : ByteToMessageDecoder{protected override void Decode(IChannelHandlerContext context, IByteBuffer input, List<object> output){byte[] array = new byte[input.ReadableBytes];input.GetBytes(input.ReaderIndex, array, 0, input.ReadableBytes);input.Clear();var temp = MessagePackHelper.DeserializeWithBinary<Message>(array);output.Add(temp);}}

5.服务端里修改：

                        pipeline.AddLast(new ServerMessagePackEncoder<Message>());
                        pipeline.AddLast(new CommonServerDecoder());

客户端里修改：

                        pipeline.AddLast(new ClientMessagePackEncoder<Message>());
                        pipeline.AddLast(new CommonClientDecoder());

6.服务端接收和发送：

        public override void ChannelRead(IChannelHandlerContext context, object message){if (message is Message oo){switch(oo.Command){case COMMAND.Message:Console.WriteLine($"解码器方式，从客户端接收:{oo.Content}:{DateTime.Now}");Message ms = new Message { Command = COMMAND.Message, Content = "服务端从客户端接收到内容后返回，我是服务端" };context.WriteAndFlushAsync(ms);return;default:Console.WriteLine($"解码器方式，客户端心跳:{oo.Content}");Message hb = new Message { Command = COMMAND.Message, Content = "服务端接收到心跳连接" };context.WriteAndFlushAsync(hb);//写入输出流return;}}}
将服务端所有要发送的位置，改成上面的写法。

客户端接收和发送：

        public override void ChannelActive(IChannelHandlerContext context){Console.WriteLine("我是客户端.");Console.WriteLine($"连接至服务端{context}.");Message ms = new Message { Command = COMMAND.Message, Content = "客户端1。" };context.WriteAndFlushAsync(ms);}public override void ChannelRead(IChannelHandlerContext context, object message){if (message is Message oo){Console.WriteLine($"Decoder方式，从服务端接收:{oo.Content}");}}

这样就使用，自定义协议加MessagePack序列化，实现了上一节一样的效果。

附加：List方式接收

如果要实现List接收。就在解码器里将消息加入List。

            List<Message> tl = new List<Message> { temp, new Message { Command = COMMAND.Message, Content = "888" } };
            output.Add(tl);

接收的时候做下面的判断：

            if (message is List<Message> lo)
            {
                lo.ForEach(s => Console.WriteLine($"Decoder方式，从服务端接收:{s.Content}"));
            }

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