WebSocket Server in ASP.NET CORE
一：在StartUp.cs中定义WebSocket与拦截WebSocket请求
在app.UseEndpoints()之前增加：
var webSocketOptions = new WebSocketOptions()
{
KeepAliveInterval = TimeSpan.FromSeconds(120),
};
app.UseWebSockets(webSocketOptions);
app.Use(async (context, next) =>
{
if (context.Request.Path.StartsWithSegments("/ws"))
{
if (context.WebSockets.IsWebSocketRequest)
{
using (var webSocket = await context.WebSockets.AcceptWebSocketAsync())
{
await WebSocketRoute.Connect(Configuration, env, context, webSocket);
}
}
else
{
context.Response.StatusCode = (int)HttpStatusCode.Forbidden;
}
}
else
{
await next();
}
});上面的 WebSocketRoute.Connect() 方法是后面定义的WebSocket入口。
二、定义接口、WebSocket根类，WebSocket路由
定义接口 IWebSocket.cs：
public interface IWebSocket
{
public void Open();
public bool Authentication();
/// <summary>
/// 接收消息
/// </summary>
public void Message(string Message);
public void Close();
public Task Send(string Message);
}这是顶层接口，很简单，表示所有继承的类都必须定义这些方法。
下面是第一个根类WebSocketWrapper.cs：
public class WebSocketWrapper : IWebSocket
{
public IConfiguration configuration;
public IWebHostEnvironment env;
public HttpContext context;
public System.Net.WebSockets.WebSocket ws;
public long SessionId { get; set; }
public string ControllerName { get; set; }
private static async Task SendMessage(System.Net.WebSockets.WebSocket ws, string Message)
{
byte[] buffer = new byte[1024 * 4];
byte[] msg = System.Text.Encoding.UTF8.GetBytes(Message);
Array.Copy(msg, 0, buffer, 0, msg.Length);
await ws.SendAsync(new ArraySegment<byte>(buffer, 0, msg.Length), WebSocketMessageType.Text, true, CancellationToken.None);
}
public WebSocketWrapper(IConfiguration configuration, IWebHostEnvironment env, HttpContext context, System.Net.WebSockets.WebSocket ws)
{
this.configuration = configuration;
this.env = env;
this.context = context;
this.ws = ws;
}
public virtual void Open()
{
}
public virtual bool Authentication()
{
return true;
}
/// <summary>
/// 接收消息
/// </summary>
public virtual void Message(string Message)
{
}
public virtual void Close()
{
}
public virtual async Task Send(string Message)
{
await SendMessage(ws, Message);
}
}下面是WebSocket路由入口WebSocketRoute.cs，使用了反射：
public class WebSocketRoute
{
public class Connection
{
public long SessionId;
public string ControllerName;
public object Instance;
public DateTime Datecreated;
}
public static List<Connection> Connections = new List<Connection>();
public static async Task Connect(IConfiguration configuration, IWebHostEnvironment env, HttpContext context, System.Net.WebSockets.WebSocket ws)
{
string ControllerName = context.Request.Path.ToString().Substring(3).TrimStart('/');
string TypeName = ControllerName + "WebSocket";
Assembly assembly = Assembly.GetExecutingAssembly();
object instance = assembly.CreateInstance(TypeName, true, BindingFlags.Default, null, new object[] { configuration, env, context, ws }, System.Globalization.CultureInfo.CurrentCulture, null);
Type wsType = Type.GetType(TypeName);
#region 身份认证
MethodInfo miAuth = wsType.GetMethod("Authentication");
if (miAuth != null)
{
bool Status = miAuth.Invoke(instance, new object[0]).ToString().ToBoolean();
if (!Status)
{
await ws.CloseAsync(new WebSocketCloseStatus() { }, "", CancellationToken.None);
return;
}
}
#endregion
long SessionId;
#region 生成sessionid
string SessionIdFile = Path.Combine(env.ContentRootPath, "SessionIds.txt");
long Timestamp = new DateTimeOffset(DateTime.UtcNow).ToUnixTimeSeconds();
byte[] TimeBytes = BitConverter.GetBytes(Timestamp);
if (!File.Exists(SessionIdFile))
{
SessionId = 1000000;
byte[] SidBytes = BitConverter.GetBytes(SessionId);
using (FileStream fs = new FileStream(SessionIdFile, FileMode.Append, FileAccess.Write))
{
fs.Write(TimeBytes, 0, TimeBytes.Length);
fs.Write(SidBytes, 0, SidBytes.Length);
}
}
else
{
using (FileStream fs = new FileStream(SessionIdFile, FileMode.Open, FileAccess.ReadWrite))
{
fs.Position = fs.Length - 8;
byte[] buf = new byte[8];
fs.Read(buf, 0, buf.Length);
SessionId = BitConverter.ToInt64(buf, 0) + 1;
byte[] SidBytes = BitConverter.GetBytes(SessionId);
fs.Write(TimeBytes, 0, TimeBytes.Length);
fs.Write(SidBytes, 0, SidBytes.Length);
}
}
#endregion
PropertyInfo Sid = wsType.GetProperty("SessionId");
if(Sid != null)
{
Sid.SetValue(instance, SessionId);
}
PropertyInfo Name = wsType.GetProperty("ControllerName");
if (Name != null)
{
Name.SetValue(instance, ControllerName);
}
Connections.Add(new Connection() { SessionId = SessionId, ControllerName = ControllerName, Instance = instance, Datecreated = DateTime.Now });
Console.WriteLine("Sid={0}, Name={1}", Sid.GetValue(instance).ToString(), ControllerName);
#region 绑定Open事件
MethodInfo onOpen = wsType.GetMethod("Open");
if (onOpen != null)
{
onOpen.Invoke(instance, new object[0]);
}
#endregion
var buffer = new byte[1024 * 4];
WebSocketReceiveResult result = await ws.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
while (!result.CloseStatus.HasValue)
{
#region 绑定Message接收消息事件
MethodInfo onMessage = wsType.GetMethod("Message");
if (onMessage != null)
{
string Txt = System.Text.Encoding.UTF8.GetString(buffer, 0, result.Count);
onMessage.Invoke(instance, new object[] { Txt });
}
#endregion
//await ws.SendAsync(new ArraySegment<byte>(buffer, 0, result.Count), result.MessageType, result.EndOfMessage, CancellationToken.None);
result = await ws.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
}
#region 绑定Close事件
Connection conn = Connections.Where(n => n.SessionId == SessionId).First();
Connections.Remove(conn);
await ws.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
MethodInfo onClose = wsType.GetMethod("Close");
if (onClose != null)
{
onClose.Invoke(instance, new object[0]);
}
#endregion
}
}下面是业务层定义WebSocket控制器，约定如下：
1、控制器文件名必须是 XXXWebSocket.cs，XXX是控制器的名称，类名也必须是 XXXWebSocket，此类必须继承自WebSocketWrapper。
2、按接口IWebSocket的定义，派生类必须定义5个方法：Open, Authentication, Message, Close, Send。身份验证在Authentication方法中实现。不同的控制器有不同的身份验证方法。如果未定义Authentication方法，表示不进行身份验证。
测试 TestWebSocket.cs：
public class TestWebSocket : WebSocketWrapper
{
public int UserId;
public TestWebSocket(IConfiguration configuration, IWebHostEnvironment env, HttpContext context, System.Net.WebSockets.WebSocket ws) :base(configuration, env, context, ws)
{
}
public override void Open()
{
Console.WriteLine("建立连接=" + this.SessionId);
}
public override bool Authentication()
{
int Uid = context.Request.Query["userid"][0].ToInt32();
Console.WriteLine("认证参数=" + Uid.ToString());
this.UserId = Uid;
bool Result = UserId > 0;
return Result;
}
/// <summary>
/// 接收消息
/// </summary>
public override void Message(string Message)
{
Console.WriteLine("收到消息="+Message+"(Sid:"+this.SessionId + ")");
}
public override void Close()
{
Console.WriteLine("关闭连接=" + this.SessionId);
}
public override async Task Send(string Message)
{
///业务逻辑写在这里
await base.Send(Message);
}
}由于在WebSocketRoute中缓存了所有的WebSocket连接，因此找到指定的连接，并向该连接发送消息是可行了。在 ASP.NET CORE的控制器中访问缓存中的连接，就能实现 HTTP2WebSocket了：
public async Task Http2WebSocket()
{
string Name = Request.Query["name"]; //WebSocket 控制器名称
int UserId = Request.Query["userid"][0].ToInt32(); //该控制器下的指定身份
string Msg = Request.Query["msg"]; //需要向浏览器发送的消息
IEnumerable<ApiCore.WebSocketRoute.Connection> conns = ApiCore.WebSocketRoute.Connections.Where(n => n.ControllerName == Name);
List<TestWebSocket> items = new List<TestWebSocket>();
foreach (ApiCore.WebSocketRoute.Connection item in conns)
{
TestWebSocket t = (TestWebSocket)item.Instance;
if (t.UserId != UserId) continue;
items.Add(t);
}
List<Task> listOfTasks = new List<Task>();
foreach (TestWebSocket item in items)
{
listOfTasks.Add(item.Send(Msg));
}
await Task.WhenAll(listOfTasks);
}浏览器中这样连接：
var ws;
function WebSocketTest(uid) {
if (!"WebSocket" in window) {
alert("您的浏览器不支持 WebSocket!");
return;
}
if (ws != undefined) return;
ws = new WebSocket("ws://www.myserver.com:5001/ws/Test?userid=" + uid);
ws.onopen = function () {
$("#logs").append("已连接<br/>");
};
ws.onmessage = function (evt) {
var msg = evt.data;
$("#logs").append("接收到:" + msg + "<br />");
};
ws.onclose = function () {
// 关闭 websocket
$("#logs").append("已断开<br />");
ws = undefined;
};
}
2021-06-21
ASP.NET CORE
蔡大卫，广东揭阳人氏，现居深圳，从事互联网行业，专注程序编码工作20年。目前正在创业。
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