一.应用场景: 在项目中有一个地方需要定时查询数据库是否有数据，如果有则显示在界面上。

二.可以使用ajax定时查询来做：

var inter = window.setInterval(refreshData,30000);   //每三十秒调用一次
function refreshData() {

        $.ajax({

            cache: false,

            type: "POST",

            url: "@(Url.Action("TJInfoData", "TJInfo"))",

            success: function (data) {

                if (data.code == "200") {

                    //alert(data.msg.Name);

                    //更新数据

                }

                else {

                    //alert(data.msg);

                    //无数据时，界面要清数据

                    //基本信息

                    $("#Lsh").text("");

                }

            },

            error: function(xhr, ajaxOptions, thrownError) {

                alert(thrownError);

            }

        });

    }

三.ajax定时查询虽然简单明了，但是听说了signalr 后决定试下。

1. 添加包，nuget 搜索SignaR 安装即可。

2. 在前端页面添加js：

<!--Reference the SignalR library. -->

<script src="~/Scripts/jquery.signalR-2.2.2.js"></script>

<!--Reference the autogenerated SignalR hub script. -->

<script src="~/signalr/hubs"></script>

<!--Reference the StockTicker script. -->

<script src="~/Scripts/TJDataQueryScript.js"></script>

其中 TJDataQueryScript.js 为利用signaR 进行通信的方法。

3. 首先创建路由：

using Microsoft.Owin;

using Owin;

[assembly: OwinStartup(typeof(OfficialAgentWeb.SignalRHub.Startup))]

namespace OfficialAgentWeb.SignalRHub

{

    public class Startup

    {

        public void Configuration(IAppBuilder app)

        {

            // Any connection or hub wire up and configuration should go here

            app.MapSignalR();

        }

    }

}

再创建连接器：

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using Data.Domain;

using Data.Infrastructure;

using Data.Log4Net;

using Data.Services;

using Microsoft.AspNet.SignalR;

using Microsoft.AspNet.SignalR.Hubs;

namespace OfficialAgentWeb.SignalRHub

{

    [HubName("TJDataHubMini")]

    public class TJDataHub : Hub

    {

        private readonly TJDataQuery _tjdata;

        public TJDataHub() : this(TJDataQuery.Instance) { }

        public TJDataHub(TJDataQuery stockTicker)

        {

            _tjdata = stockTicker;

        }

        public override Task OnConnected()

        {

            var AdminId = Context.QueryString["AdminId"];

            var YewuIsSuper = Context.QueryString["YewuIsSuper"];

            WriteLog.Info("OnConnected: ConnectionId=" + Context.ConnectionId + ",AdminId="+ AdminId + ",YewuIsSuper=" + YewuIsSuper);

            if (!_tjdata.ConnectIdAdminIdDic.ContainsKey(Context.ConnectionId))

            {

                _tjdata.ConnectIdAdminIdDic.Add(Context.ConnectionId, AdminId);

            }

            if (!_tjdata.ConnectIdIsSuperDic.ContainsKey(Context.ConnectionId))

            {

                _tjdata.ConnectIdIsSuperDic.Add(Context.ConnectionId, YewuIsSuper);

            }

            //

            int adminIdInt = 0;

            int.TryParse(AdminId, out adminIdInt);

            bool YewuIsSuperBool = YewuIsSuper.ToLower().Equals("true") ? true : false;

            var signalRConnectIdService = EngineContext.Current.Resolve<ISignalRConnectIdService>();

            signalRConnectIdService.Insert(new M_SignalRConnectId { ConnectId = Context.ConnectionId, AdminId = adminIdInt, YewuIsSuper = YewuIsSuperBool, IsDeleted = false, IsActive = false });

            return base.OnConnected();

        }

        public override Task OnDisconnected(bool stopCalled)

        {

            var AdminId = Context.QueryString["AdminId"];

            var YewuIsSuper = Context.QueryString["YewuIsSuper"];

            WriteLog.Info("OnDisconnected: ConnectionId=" + Context.ConnectionId + ",AdminId="+ AdminId + ", YewuIsSuper=" + YewuIsSuper);

            if (_tjdata.ConnectIdAdminIdDic.ContainsKey(Context.ConnectionId))

            {

                _tjdata.ConnectIdAdminIdDic.Remove(Context.ConnectionId);

            }

            if (_tjdata.ConnectIdIsSuperDic.ContainsKey(Context.ConnectionId))

            {

                _tjdata.ConnectIdIsSuperDic.Remove(Context.ConnectionId);

            }

            //

            int adminIdInt = 0;

            int.TryParse(AdminId, out adminIdInt);

            var signalRConnectIdService = EngineContext.Current.Resolve<ISignalRConnectIdService>();

            var cidQ = signalRConnectIdService.GetByConnectId(Context.ConnectionId);

            if (cidQ != null)

            {

                var cidL = cidQ.ToList();

                if (!(cidL == null || cidL.Count<1))

                {

                    cidL.ForEach(p => p.IsDeleted = true);

                    signalRConnectIdService.Update(cidL);

                }

            }

            return base.OnDisconnected(stopCalled);

        }

        public override Task OnReconnected()

        {

            var AdminId = Context.QueryString["AdminId"];

            var YewuIsSuper = Context.QueryString["YewuIsSuper"];

            WriteLog.Info("OnReconnected: ConnectionId=" + Context.ConnectionId + ",AdminId=" + AdminId + ",YewuIsSuper=" + YewuIsSuper);

            if (!_tjdata.ConnectIdAdminIdDic.ContainsKey(Context.ConnectionId))

            {

                _tjdata.ConnectIdAdminIdDic.Add(Context.ConnectionId, AdminId);

            }

            if (!_tjdata.ConnectIdIsSuperDic.ContainsKey(Context.ConnectionId))

            {

                _tjdata.ConnectIdIsSuperDic.Add(Context.ConnectionId, YewuIsSuper);

            }

            //

            int adminIdInt = 0;

            int.TryParse(AdminId, out adminIdInt);

            bool YewuIsSuperBool = YewuIsSuper.ToLower().Equals("true") ? true : false;

            var signalRConnectIdService = EngineContext.Current.Resolve<ISignalRConnectIdService>();

            signalRConnectIdService.Insert(new M_SignalRConnectId { ConnectId = Context.ConnectionId, AdminId = adminIdInt, YewuIsSuper = YewuIsSuperBool, IsDeleted = false, IsActive = false });

            return base.OnReconnected();

        }

        public IEnumerable<TJDataForTimer> GetAllStocks()

        {

            return null;

        }

        [HubMethodName("NewContosoChatMessage")]

        public void NewContosoChatMessage(string cid)

        {

            WriteLog.Info("TJDataQuery--IsAlive--cid=" + cid);

        }

    }

}

创建一个单例来定时发布数据 给客户端：

using Bll.Admin;

using Data.Domain;

using Data.Infrastructure;

using Data.Log4Net;

using Data.Services;

using Microsoft.AspNet.SignalR;

using Microsoft.AspNet.SignalR.Hubs;

using OfficialAgentWeb.Controllers;

using System;

using System.Collections.Concurrent;

using System.Collections.Generic;

using System.Linq;

using System.Threading;

using System.Web;

using System.Web.SessionState;

namespace OfficialAgentWeb.SignalRHub

{

    public class TJDataQuery

    {

        // Singleton instance

        private readonly static Lazy<TJDataQuery> _instance = new Lazy<TJDataQuery>(() => new TJDataQuery(GlobalHost.ConnectionManager.GetHubContext<TJDataHub>().Clients));

        private readonly ConcurrentDictionary<string, TJDataForTimer> _stocks = new ConcurrentDictionary<string, TJDataForTimer>();

        private readonly object _updateStockPricesLock = new object();

        //stock can go up or down by a percentage of this factor on each change

        private readonly double _rangePercent = .002;

        private readonly TimeSpan _updateInterval = TimeSpan.FromSeconds(30); //TimeSpan.FromMilliseconds(250);

        private readonly Random _updateOrNotRandom = new Random();

        //private readonly Timer _timer;

        public Timer _timer { get; set; }

        private volatile bool _updatingStockPrices = false;

        private TJDataQuery(IHubConnectionContext<dynamic> clients)

        {

            Clients = clients;

            ConnectIdAdminIdDic = new Dictionary<string, string>();

            ConnectIdIsSuperDic = new Dictionary<string, string>();

            _stocks.Clear();

            _timer = new Timer(UpdateStockPrices, null, _updateInterval, _updateInterval);

        }

        public static TJDataQuery Instance

        {

            get

            {

                return _instance.Value;

            }

        }

        private IHubConnectionContext<dynamic> Clients

        {

            get;

            set;

        }

        //ConnectId 和 AdminId 的字典

        public Dictionary<string, string> ConnectIdAdminIdDic

        {

            get;

            set;

        }

        //ConnectId 和 IsSuperDic 的字典

        public Dictionary<string, string> ConnectIdIsSuperDic

        {

            get;

            set;

        }

        public IEnumerable<TJDataForTimer> GetAllStocks()

        {

            //return _stocks.Values;

            return null;

        }

        private void UpdateStockPrices(object state)

        {

            lock (_updateStockPricesLock)

            {

                if (!_updatingStockPrices)

                {

                    _updatingStockPrices = true;

                    //from database

                    var signalRConnectIdService = EngineContext.Current.Resolve<ISignalRConnectIdService>();

                    var cidQ = signalRConnectIdService.GetAllConnect();

                    if (cidQ != null)

                    {

                        var cidL = cidQ.ToList();

                        if (!(cidL == null || cidL.Count < 1))

                        {

                            //根据adminid查数据，然后分发推送到客户端。

                            Dictionary<int, List<string>> adminIdDic = new Dictionary<int, List<string>>();

                            foreach (var p in cidL)

                            {

                                if (!adminIdDic.ContainsKey(p.AdminId))

                                    adminIdDic.Add(p.AdminId, new List<string> { p.ConnectId });

                                else

                                    adminIdDic[p.AdminId].Add(p.ConnectId);

                            }

                            //

                            foreach (var a in adminIdDic)

                            {

                                var ayewu = false;

                                var cidL1 = cidL.Where(x => x.AdminId == a.Key).ToList();

                                if (!(cidL1 == null || cidL1.Count < 1))

                                {

                                    ayewu = cidL1[0].YewuIsSuper;

                                }

                                var m = GetTJDataQuery(a.Key, ayewu);

                                //分发

                                foreach (var connectid in a.Value)

                                {

                                    WriteLog.Info("BroadcastStockPrice begin: AdminId=" + a.Key + ",connectid="+ connectid);

                                    BroadcastStockPrice(m, connectid);

                                }

                            }

                        }

                    }

                    //

                    Clients.All.IsAlive();

                    //foreach (var a in ConnectIdAdminIdDic)

                    //{

                    //    var m = GetTJDataQuery(a.Value, a.Key);

                    //    WriteLog.Info("BroadcastStockPrice begin: AdminId=" + a.Value);

                    //    BroadcastStockPrice(m, a.Key);

                    //}

                    _updatingStockPrices = false;

                }

            }

        }

        private void BroadcastStockPrice(TJDataForTimer stock, string connectId)

        {

            if (stock == null || (!stock.code.Equals("200")))

            {

                WriteLog.Info("updateStockPrice begin: connectId=" + connectId + ", 推送空的内容");

            }

            else

            {

                WriteLog.Info("updateStockPrice begin: connectId=" + connectId + ", 推送了：" + (stock.msg == null ? "" : stock.msg.Name));

            }

            Clients.Client(connectId).updateStockPrice(stock);

            //Clients.All.updateStockPrice(stock);

        }

        private TJDataForTimer GetTJDataQuery(int AdminId, bool YewuIsSuperBool)

        {

            TJDataForTimer value = new TJDataForTimer();

            B_TJInfo b = new B_TJInfo();

            //int intAdmin = 0;

            //int.TryParse(AdminId, out intAdmin);

            //审核数量，待审核：0      今天已审核：0      今天审核通过：0      今天审核不通过：0

            if (AdminId<1)

            {

                WriteLog.Info("GetTJDataQuery AdminId <0: AdminId=" + AdminId);

                return null;

            }

            count_sh count_Sh = b.GetCountSh(AdminId, YewuIsSuperBool);

            if (count_Sh == null)

            {

            }

            //

            M_TJInfo m = b.GetNewSingle(AdminId, YewuIsSuperBool);

            if (m == null)

            {

                WriteLog.Info("GetTJDataQuery GetNewSingle is null");

                //return null;

                value.code = "401";

                value.msgCountsh = count_Sh;

                return value;

            }

            //TJInfoDetail

            List<M_TJInfoDetail> detailList = b.GetDetail(m.Id);

            if (detailList == null || detailList.Count < 1)

            {

            }

            //MachineCheck

            List<M_MachineCheck> machineList = b.GetMachine(m.OperateNo);

            if (machineList == null || machineList.Count < 1)

            {

            }

            value.code = "200";

            value.msg = m;

            value.msgDetail = detailList;

            value.msgMachine = machineList[0];

            value.msgCountsh = count_Sh;

            return value;

            //return Json(new { code = "200", msg = m, msgDetail = detailList, msgMachine = machineList[0], msgCountsh = count_Sh });

        }

    }

}

4. 运行时碰到的问题：

A. 客户端可以传递参数给服务器：

$.connection.hub.qs = { 'AdminId': $("#AdminIdHid").val(), 'YewuIsSuper': $("#YewuIsSuperHid").val()};

在服务端比如在OnConnected()里 使用 var AdminId = Context.QueryString["AdminId"]; 获取值。

B. 每次连接都会调用OnConnected()方法，失去连接会调用OnDisconnected 方法，由于超时等原因暂时连不上，然后又连上的调用OnReconnected重连，但是重连后connectId会变。

在OnConnected() 方法里把connectId 保存到数据库里。

在OnDisconnected 方法里 更新该connectId为失去连接。

但是在测试过程中，反复刷新该页面，也有可能出现某次OnDisconnected 没有调用的情况。

所有就会出现数据库里发现有3个connectId 在连接， 但是其实可能只有1个客户端在连接。

暂时想到的解决方法是：

服务端启动一个定时器每30分钟调用一次，调用客户端的方法，而客户端的方法是传递connectId到服务端的另外一个方法里。在服务器的该方法里可以根据connectId设置该客户端为活动状态。

服务器端创建一个任务Task，定时跑，查询连接表，如果发现该connectId 不是活动状态，则更新此数据。

代码：

Clients.All.IsAlive();

服务端调用客户端的IsAlive 方法。

然后客户端：

var ticker = $.connection.TJDataHubMini;

ticker.client.IsAlive = function () {

        var clinetConectId = $.connection.hub.id+'';

        console.log('clinetConectId=' + clinetConectId);

        ticker.server.NewContosoChatMessage(clinetConectId).done(function () {

            console.log('IsAliveService done');

        });

    }

客户端得到 ConectId 后调用服务端的 NewContosoChatMessage 的方法。

[HubMethodName("NewContosoChatMessage")]

        public void NewContosoChatMessage(string cid)

        {

            WriteLog.Info("TJDataQuery--IsAlive--cid=" + cid);

        }

可以在 此 NewContosoChatMessage 方法里更新数据表。

服务端创建任务参见另外一篇文章。

最新文章

  1. HTML2
  2. Cannot change version of project facet Dynamic Web Module to 3.0
  3. UCOS-2 消息邮箱与队列
  4. python 调用内部类的两种方法
  5. 批量修改数据sql
  6. mvc5 + ef6 + autofac搭建项目（repository+uow）（二）
  7. Codeforces 527D Clique Problem
  8. nignx开启expires后相关资源不显示的问题
  9. Tomcat 配置篇
  10. iOS 开发的几种手势
  11. iOS基础 - 多线程线程
  12. CollapsingToolbarLayout学习笔记
  13. [转载] NodeJS无所不能：细数十个令人惊讶的NodeJS开源项目
  14. uCos-II中任务的同步与通信
  15. python全栈开发笔记---------函数
  16. vsCode---中文化
  17. uniGUI中Cookies使用中文汉字的方法（使用EncodeString函数编码）
  18. Selenium自动化Page模式（Python)
  19. springcloud配置详解
  20. linux tftp 服务

热门文章

  1. Flutter 下载篇 - 贰 | 当下载器遇上切换网络库
  2. chm文档生成-&gt;Sandcastle使用帮助
  3. Python elasticsearch 报错及解决方法
  4. 周练3（php反序列化）
  5. scrapy 爬取酷狗热门歌手音乐
  6. C - Functions again CodeForces - 789C (dp、思维)
  7. NFS服务器搭建与autofs自动挂载
  8. windows与linux下的路径区别
  9. element-ui upload自定义formdata上传文件和参数
  10. react native SectionList组件实现多选