SignalR+NetCore 简单笔记

    public class ChatHub : Hub
    {
        private static Dictionary<string, string> AllUserDic = new Dictionary<string, string>();
        public async Task SendMessage(string user, string reUser, string message)
        {
            //与包含自己的所有客户端通讯（收到消息）
            //await Clients.All.SendAsync("ReceiveMessage", user, message);
            //与除自己之外的其它客户端通讯（收到消息）
            //await Clients.Others.SendAsync("ReceiveMessage", user, message);
            //仅与自己通讯（收消息）
            //await Clients.Caller.SendAsync("ReceiveMessage", user, message);
            //if (AllUserDic.ContainsKey(user))
            //    AllUserDic[user] = Context.ConnectionId;
            //else
            //    AllUserDic.Add(user, Context.ConnectionId);

           
            
            if (string.IsNullOrEmpty(reUser))
                await Clients.Others.SendAsync("ReceiveMessage", user, reUser, message);
            else
            {
                var re = Clients.User(reUser);
                if (re == null)
                    await Clients.Caller.SendAsync("ReceiveMessage", user, reUser, "消息发送失败");
                else
                    await Clients.User(reUser).SendAsync("ReceiveMessage", user, reUser, message);
            }
        }
　　}

    /// <summary>
    /// 登陆用户基本信息
    /// </summary>
    public class UserInfo : IUserIdProvider
    {
        public string GetUserId(HubConnectionContext connection)
        {
            //这里可以重写用户ID，重写后可以直接在Hub的派生类中（ChatHub）直接指定用户ID 推送消息
            //var requestContext = connection.GetHttpContext();
            //requestContext.Request.Session
            //requestContext.Request.QueryString["xxx"]
            //requestContext.Request.Cookies[""]
            
            //此处模拟一个用户ID，
            return Guid.NewGuid().ToString();
        }
    }

    public class ChatHub : Hub
    {
        /// <summary>
        /// 发送消息
        /// </summary>
        /// <param name="user">消息发送人（这个只是用来展示 是谁发的而已）</param>
        /// <param name="reUserId">收消息的人员Id 这里这个ID，就是上面 GetUserId里面重写的值</param>
        /// <param name="message">消息内容</param>
        /// <returns></returns>
        public async Task SendMessage(string user, string reUserId, string message)
        {
            //其实user不用传，可以从 Context.User.Claims 或 Context.GetHttpContext() 里面拿到user的所有信息
            //此时传入user 只是用来偷懒，因为demo没有做登陆之类的

　　　　　　　//如果 没传收消息的人，就发给所有除自己之外的 所有在线的人，反之仅发给指定人
            if (string.IsNullOrEmpty(reUserId))
                await Clients.Others.SendAsync("ReceiveMessage", user, reUserId, message);
            else
                await Clients.User(reUserId).SendAsync("ReceiveMessage", user, reUserId, message);
        }
　　　　
        public override Task OnConnectedAsync()
        {
            var connectionId = Context.ConnectionId;
            var identityName = Context.User.Identity.Name;
     
            return base.OnConnectedAsync();
        }
        public override Task OnDisconnectedAsync(Exception exception)
        {
            return base.OnDisconnectedAsync(exception);
        }
    }

//void ConfigureServices(IServiceCollection services)j里面加
            services.AddSingleton<IUserIdProvider,UserInfo>();
            services.AddSignalR();

//void Configure(IApplicationBuilder app, IHostingEnvironment env)里面不变
            app.UseSignalR(routes =>
            {
                routes.MapHub<ChatHub>("/chatHub");
            });