SignalR 的应用

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。