C#中一个高性能异步Socket封装库的实现思路分享

在实现高性能异步Socket封装库时，我们可以采用以下步骤：

步骤一：创建Socket

在使用Socket进行网络通信之前，我们需要创建一个Socket实例。可以使用以下代码创建一个Socket：

Socket socket = new Socket(SocketType.Stream, ProtocolType.Tcp);

步骤二：连接服务器

如果需要与服务器进行通信，可以使用Connect方法连接服务器。以下是示例代码：

IPAddress ipAddress = IPAddress.Parse("127.0.0.1");
IPEndPoint remoteEP = new IPEndPoint(ipAddress, 11000);

socket.Connect(remoteEP);

步骤三：发送数据

发送数据可以使用Socket的Send方法。以下是示例代码：

byte[] bytesToSend = Encoding.ASCII.GetBytes("Hello World!");

int bytesSent = socket.Send(bytesToSend);

步骤四：接收数据

接收数据需要使用Socket的Receive方法。以下是示例代码：

byte[] bytesReceived = new byte[1024];

int bytes = socket.Receive(bytesReceived);
string dataReceived = Encoding.ASCII.GetString(bytesReceived, 0, bytes);

步骤五：关闭Socket

在使用Socket完成通信后，需要使用Close方法关闭Socket。以下是示例代码：

socket.Shutdown(SocketShutdown.Both);
socket.Close();

步骤六：异步Socket

为了实现高性能异步Socket封装库，我们需要使用异步Socket。以下是示例代码：

public static async Task<int> Send(Socket socket, byte[] data)
{
    return await Task.Factory.FromAsync<int>(socket.BeginSend(data, 0, data.Length, SocketFlags.None, null, socket),
                                             socket.EndSend);
}

public static async Task<string> Receive(Socket socket)
{
    byte[] buffer = new byte[1024];
    int bytesReceived = await Task.Factory.FromAsync<int>(socket.BeginReceive(buffer, 0, buffer.Length, SocketFlags.None, null, socket),
                                                          socket.EndReceive);

    return Encoding.ASCII.GetString(buffer, 0, bytesReceived);
}

以上异步方法示例使用了Task.Factory.FromAsync方法将BeginXXX和EndXXX方法封装为一个异步方法，以便于利用async/await语法糖简化异步操作。

示例一：基于异步Socket的Echo服务器

我们可以基于异步Socket实现一个Echo服务器，以下是示例代码：

public class EchoServer
{
    private Socket _listener;

    public EchoServer()
    {
        _listener = new Socket(SocketType.Stream, ProtocolType.Tcp);
        _listener.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 11000));
        _listener.Listen(100);
    }

    public async Task Start()
    {
        while (true)
        {
            Socket socket = await Task.Factory.FromAsync<Socket>(_listener.BeginAccept, _listener.EndAccept, null);
            Console.WriteLine("Client connected: {0}", socket.RemoteEndPoint);

            Task.Factory.StartNew(async () => await HandleClient(socket), TaskCreationOptions.LongRunning);
        }
    }

    private async Task HandleClient(Socket socket)
    {
        try
        {
            while (true)
            {
                string dataReceived = await SocketExtensions.Receive(socket);
                Console.WriteLine("Received: {0}", dataReceived);

                int bytesSent = await SocketExtensions.Send(socket, Encoding.ASCII.GetBytes(dataReceived));
                Console.WriteLine("Sent: {0} bytes", bytesSent);
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error: {0}", ex.Message);
        }
        finally
        {
            socket.Shutdown(SocketShutdown.Both);
            socket.Close();
            Console.WriteLine("Client disconnected: {0}", socket.RemoteEndPoint);
        }
    }
}

以上示例代码实现了基于异步Socket的Echo服务器。当客户端连接到服务器后，服务器会接收来自客户端的数据，并将接收到的数据原样发送回客户端。

示例二：基于异步Socket的文件上传服务器

我们还可以基于异步Socket实现一个文件上传服务器，以下是示例代码：

public class FileUploadServer
{
    private Socket _listener;

    public FileUploadServer()
    {
        _listener = new Socket(SocketType.Stream, ProtocolType.Tcp);
        _listener.Bind(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 11000));
        _listener.Listen(100);
    }

    public async Task Start()
    {
        while (true)
        {
            Socket socket = await Task.Factory.FromAsync<Socket>(_listener.BeginAccept, _listener.EndAccept, null);
            Console.WriteLine("Client connected: {0}", socket.RemoteEndPoint);

            Task.Factory.StartNew(async () => await HandleClient(socket), TaskCreationOptions.LongRunning);
        }
    }

    private async Task HandleClient(Socket socket)
    {
        try
        {
            byte[] fileLengthBuffer = new byte[sizeof(long)];
            await SocketExtensions.Receive(socket, fileLengthBuffer);

            long fileLength = BitConverter.ToInt64(fileLengthBuffer, 0);

            byte[] fileNameBytes = new byte[fileLength];
            await SocketExtensions.Receive(socket, fileNameBytes);

            string fileName = Encoding.UTF8.GetString(fileNameBytes);

            Console.WriteLine("File name: {0}", fileName);

            using (FileStream fileStream = new FileStream(fileName, FileMode.Create, FileAccess.Write))
            {
                byte[] buffer = new byte[1024];
                int bytesReceived;

                while ((bytesReceived = await SocketExtensions.Receive(socket, buffer)) > 0)
                {
                    await fileStream.WriteAsync(buffer, 0, bytesReceived);
                }
            }

            Console.WriteLine("File uploaded: {0}", fileName);
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error: {0}", ex.Message);
        }
        finally
        {
            socket.Shutdown(SocketShutdown.Both);
            socket.Close();
            Console.WriteLine("Client disconnected: {0}", socket.RemoteEndPoint);
        }
    }
}

以上示例代码实现了基于异步Socket的文件上传服务器。客户端可以使用以下代码上传文件：

public static async Task UploadFile(string ipAddress, int port, string filePath)
{
    using (Socket socket = new Socket(SocketType.Stream, ProtocolType.Tcp))
    {
        await socket.ConnectAsync(IPAddress.Parse(ipAddress), port);
        Console.WriteLine("Connected to server");

        FileInfo fileInfo = new FileInfo(filePath);

        byte[] fileLengthBuffer = BitConverter.GetBytes(fileInfo.Name.Length);
        await SocketExtensions.Send(socket, fileLengthBuffer);

        byte[] fileNameBytes = Encoding.UTF8.GetBytes(fileInfo.Name);
        await SocketExtensions.Send(socket, fileNameBytes);

        using (FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
        {
            byte[] buffer = new byte[1024];
            int bytesSent;

            while ((bytesSent = await fileStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
            {
                await SocketExtensions.Send(socket, buffer.Take(bytesSent).ToArray());
            }
        }

        Console.WriteLine("File uploaded");
    }
}

以上示例代码实现了客户端上传文件至基于异步Socket的服务器。