C# 使用Pipelines处理Socket数据包

写在前面

在上一篇中对Pipelines进行简单的了解，同时也留下了未解的问题，如何将Pipelines类库运用到Socket通讯过程中来解决粘包和分包。链接地址如下：初识System.IO.Pipelines https://rjcql.blog.csdn.net/article/details/135211047

这一篇做了一个完整的demo，使用Pipelines接收和处理来自多个客户端发出的消息；相对于以往在报文包头放包体长度再结合结束符来判断的方式，确实要简洁了许多。

代码实现

服务端实现

using System.Net.Sockets;
using System.Net;
using System.Text;

class Program
{
    static async Task Main()
    {
        SocketServerForPiplines();
    }

    static async void SocketServerForPiplines()
    {
        Console.WriteLine("Socket Server");

        // 创建服务端Socket对象
        var serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        serverSocket.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9090));
        serverSocket.ReceiveTimeout = 1000;
        serverSocket.SendTimeout = 1000;
        serverSocket.Listen(1000);
        Console.WriteLine("服务端启动监听");

        while (true)
        {
            var clientSocket = serverSocket.Accept();

            Console.WriteLine("有客户端连上了");

            var handler = new PiplinesHandler(clientSocket);
            await handler.StartReceiveAsync();
        }

        Console.ReadLine();
    }
}

PiplinesHandler 类：

using System;
using System.Buffers;
using System.Collections.Generic;
using System.IO.Pipelines;
using System.Linq;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace PipelinesTester
{
    public class PiplinesHandler
    {
        private const int _minimumBufferSize = 512;
        private Socket _socket;
        private Pipe _pipe;

        public PiplinesHandler(Socket socket)
        {
            _socket = socket;
            var options = new PipeOptions(pauseWriterThreshold: 4096, resumeWriterThreshold: 1024);
            _pipe = new Pipe(options);
        }

        public async Task StartReceiveAsync()
        {
            Task receiveTask = ReceiveMessageAsync();
            Task processTask = ProcessMessageAsync();

            await Task.WhenAll(receiveTask, processTask);
        }


        private async Task ReceiveMessageAsync()
        {
            PipeWriter writer = _pipe.Writer;

            while (true)
            {
                try
                {
                    //从writer申请缓冲区
                    Memory<byte> memory = writer.GetMemory(_minimumBufferSize);
                    //从socket读取数据，直接写入到缓冲区中，即直接写入了PipeWriter中        
                    int bytesRead = await _socket.ReceiveAsync(memory, SocketFlags.None);
                    if (bytesRead == 0)
                    {
                        break;
                    }
                    //前移写标志位
                    writer.Advance(bytesRead);
                    //通知Reader，可以读取了
                    var result = await writer.FlushAsync();

                    if (result.IsCompleted)
                        break;
                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                    break;
                }

            }

            await writer.CompleteAsync();

            try
            {
                _socket.Shutdown(SocketShutdown.Both);
                _socket.Close();
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }
        }

        private async Task ProcessMessageAsync()
        {
            PipeReader _pipeReader = _pipe.Reader;

            while (true)
            {
                //读取消息
                var result = await _pipeReader.ReadAsync();
                var buffer = result.Buffer;
                //查找结束符            
                SequencePosition? position = buffer.PositionOf((byte)'\n');

                if (position == null)
                {
                    continue;
                }

                // 处理消息
                var line = buffer.Slice(0, position.Value);
                string msg = Encoding.UTF8.GetString(line);
                Console.WriteLine(msg);

                // 前移PipeReader
                buffer = buffer.Slice(buffer.GetPosition(1, position.Value));
                _pipeReader.AdvanceTo(buffer.Start, buffer.End);

                // Stop reading if there's no more data coming.
                if (result.IsCompleted)
                {
                    break;
                }
            }

            await _pipeReader.CompleteAsync();
        }
    }
}

客户端实现

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

class Program
{
    static void Main(string[] args)
    {
        TcpClientTest();
    }

    static void TcpClientTest()
    {
        Console.WriteLine("TcpClient");

        var msg = $"这是来自客户端的消息{DateTime.Now.ToString("yyyy-MM-dd:HH:mm:ss")}\n";
        var client = new TcpClient("127.0.0.1", 9090);
        var sendStream = client.GetStream();
        var sendBytes = Encoding.Default.GetBytes(msg);
        sendStream.Write(sendBytes, 0, sendBytes.Length);
        sendStream.Flush();
        sendStream.Close();//关闭网络流  
        client.Close();//关闭客户端  

        Console.WriteLine(msg);

        Console.ReadLine();
    }
}

调用示例