一:Helios是什么
Helios是一套高性能的Socket通信中间件，使用C#编写。Helios的开发受到Netty的启发，使用非阻塞的事件驱动模型架构来实现高并发高吞吐量。Helios为我们大大的简化了Socket编程，它已经为我们处理好了高并**况下的解包，粘包，buffer管理等等。
GitHub：https://github.com/helios-io/helios/
二:Helios的特点
1.Powerful APIs
Takes the complexity out of socket programming with intelligent I/O, concurrency, buffer management, and pipelining APIs.
使用socket编程不再复杂。提供智能的I/O，并发，buffer管理，管道形式的API。
2.Event-Driven
Helios is Reactive - it uses a event-driven architecture to simplify development and build responsive systems that scale.
Helios是反应式的，它使用事件驱动的架构来简化开发和构建易伸缩的系统。
3.Performant
Performance is a cross-cutting concern we factor in at every level in the design of the framework in order to eliminate overhead for your apps and clients.
这个系统在开发和设计的时候都充分考虑到了性能，构建你的app和client的时候请消除这方面的顾虑。
4.Battle-Tested
Helios powers the clustering and remoting capbilities built into Akka.NET and more.
Akka.net的集群，远程功能构建在Helios之上。
三:一个基于Helios的聊天室示例
要用来演示Socket通信那么最好的示例无非就是聊天程序了。
整个解决方案包含3个项目：
1.HeliosChat.Common
这个项目里是一些公共的类型，新建完之后使用nuget添加helios的库
Message 类：所有发送的消息都是通过Message包装的，每一个消息都有一个Command跟Content来构成。
public class Message { public Command Command { get; set; } public string Content { get; set; } } Command枚举：用来描述消息的命令
public enum Command { Join, Send, } MessageConverter静态类：这个类用来转换Message对象为Byte[]，或者把Byte[]转换成Message对象。Message对象在通过Helios传输的时候需要先转成Byte[]，所以我们需要自己定义包的格式。我们用Byte[]的前四位来存放Command，Content转成Byte后从第5位开始存放。
public class MessageConverter { public static Message ToMessage(NetworkData data) { try { var commandData = data.Buffer.Take(4).ToArray(); var contentData = data.Buffer.Skip(4).Take(data.Buffer.Length - 4).ToArray(); var command = BitConverter.ToInt32(commandData,0); var content = Encoding.UTF8.GetString(contentData); return new Message() { Command = (Command)command, Content = content }; } catch (Exception exc) { Console.WriteLine("Cant convert NetworkData to Message : {0}", exc.Message); } return null; } public static byte[] ToBytes(Message message) { try { var commandBytes = BitConverter.GetBytes((int)message.Command); var messageBytes = Encoding.UTF8.GetBytes(message.Content); var bytes = new byte[commandBytes.Length + messageBytes.Length]; commandBytes.CopyTo(bytes, 0); messageBytes.CopyTo(bytes, commandBytes.Length); return bytes; } catch (Exception exc) { Console.WriteLine("Cant convert message to bytes : {0}", exc.Message); } return null; } } 2.HeliosChat.Server
不用说也知道，这是聊天室的服务端，负责连接用户及转发消息。
internal class Program { private static readonly ConcurrentDictionary<string, IConnection> Clients = new ConcurrentDictionary<string, IConnection>(); private static void Main(string[] args) { var host = IPAddress.Any; var port = 9991; Console.Title = "Server"; Console.WriteLine("Starting server on {0}:{1}", host, port); var serverFactory = new ServerBootstrap() .SetTransport(TransportType.Tcp) .Build(); var server = serverFactory.NewReactor(NodeBuilder.BuildNode().Host(host).WithPort(port)); server.OnConnection += (address, connection) => { Console.WriteLine("Connected: {0}", address); connection.BeginReceive(Receive); }; server.OnDisconnection += (reason, address) => Console.WriteLine("Disconnected: {0}; Reason: {1}", address.RemoteHost, reason.Type); server.Start(); Console.WriteLine("Running, press any key to exit"); Console.ReadKey(); } /// <summary> /// 处理接受到的消息 /// </summary> /// <param name="data"></param> /// <param name="channel"></param> public static void Receive(NetworkData data, IConnection channel) { var message = MessageConverter.ToMessage(data); switch (message.Command) { case Command.Join: JoinGroup(message.Content, channel); break; case Command.Send: Broadcast(message.Content); break; } } public static void JoinGroup(string clientName, IConnection channel) { if (Clients.TryAdd(clientName, channel)) { Broadcast(string.Format("{0} join group successful .", clientName)); } else { var errMsg = new Message() { Command = Command.Send, Content = "client name is used." }; SendMessage(channel, errMsg); } } /// <summary> /// 广播消息 /// </summary> /// <param name="clientMessage"></param> public static void Broadcast(string clientMessage) { Console.WriteLine(clientMessage); var clientName = clientMessage.Split(':')[0]; var message = new Message { Command = Command.Send, Content = clientMessage }; foreach (var client in Clients) { if (client.Key != clientName) { SendMessage(client.Value, message); } } } public static void SendMessage(IConnection connection, Message message) { var messageBytes = MessageConverter.ToBytes(message); connection.Send(new NetworkData { Buffer = messageBytes, Length = messageBytes.Length }); } } 3.HeliosChat.Client
聊天服务的客户端
internal class Program { public static IConnection Client; public static string ClientName; private static void Main(string[] args) { var host = IPAddress.Loopback; var port = 9991; var connectionFactory = new ClientBootstrap() .SetTransport(TransportType.Tcp).Build(); //New一个Client Client = connectionFactory.NewConnection(Node.Empty(), NodeBuilder.BuildNode().Host(host).WithPort(port)); Client.OnConnection += (address, connection) => { Console.WriteLine("Connect server successful."); connection.BeginReceive(Received); }; Client.OnDisconnection += (address, reason) => Console.WriteLine("Disconnected."); Console.WriteLine("Input ClientName "); ClientName = Console.ReadLine(); Console.Title = string.Format("Client {0}", ClientName); //建立连接 Client.Open(); //加入聊天组 Join(); //等待输入 WaitInput(); } public static void WaitInput() { while (true) { var input = Console.ReadLine(); if (!string.IsNullOrEmpty(input)) { var message = MakeSendMessage(input); SendMessage(Client, message); } } } /// <summary> /// Jion chat group /// </summary> public static void Join() { var message = MakeJoinMessage(); SendMessage(Client,message); } /// <summary> /// 处理接受到的消息 /// </summary> /// <param name="data"></param> /// <param name="responseChannel"></param> public static void Received(NetworkData data, IConnection responseChannel) { var message = MessageConverter.ToMessage(data); if (message.Command == Command.Send) { Console.WriteLine(message.Content); } } /// <summary> /// 构造聊天消息 /// </summary> /// <param name="input"></param> /// <returns></returns> public static Message MakeSendMessage(string input) { return new Message { Command = Command.Send, Content = string.Format("{0}:{1}", ClientName, input) }; } /// <summary> /// 构造加入组的消息 /// </summary> /// <returns></returns> public static Message MakeJoinMessage() { var message = new Message(); message.Command = Command.Join; message.Content = ClientName; return message; } public static void SendMessage(IConnection connection, Message message) { var messageBytes = MessageConverter.ToBytes(message); connection.Send(new NetworkData { Buffer = messageBytes, Length = messageBytes.Length }); } } 4.运行结果
这样一个简单的聊天室程序就完成了。
四：Helios 2.0
helios 1.0的异步编程模型是基于APM的，从helios 2.0开始会改成SocketAsyncEventArgs方式来实现异步。SocketAsyncEventArgs底层封装了IOCP，IOCP是Windows server上Socket通讯性能最高的技术，使用了IOCP的helios 2.0势必具有更高的性能，所以对于helios 2.0还是非常期待的。
示例下载：http://files.cnblogs.com/files/kklldog/HeliosChat.7z
原标题：.NET开源高性能Socket通信中间件Helios介绍及演示
关键词：.NET
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