FileSystemWatcher+SignalRでうまくいかにゃいんですー。最初Hubでやってうまくいかなかったので、とりあえずPersistentConnectionにしたけれどやっぱりうまくいかにゃい。一発目は発行してくれるんだけど、二発目以降はうんともすんともになってもげー。FileSystemWatcher自体は正常に動いていて、Changedイベントでデータ取って、までは行くけど、それをSignalRでBroadcastする、そのBroadcastが無反応系。

HomeController.cs

namespace MvcApplication4.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            // 後ろから30件、末尾から読んでるわけじゃないので割と手抜き
            var initialData = System.IO.File.ReadLines(GlobalConfig.LogPath).Reverse().Take(30);

            return View(initialData);
        }
    }
}

Index.cshtml

@model IEnumerable<string>

<h1>@MvcApplication4.SignalR.Sample.GlobalConfig.LogPath</h1>

<h2>アプリケーションログ</h2>

<button onclick="location.reload();">再読み込み</button>

<p>↑新しい</p>

<div id="newLogArea"></div>

@foreach (var item in @Model)
{
    @item<br />
}

<script src="~/bundles/jquery"></script>
<script src="~/Scripts/jquery.signalR-1.1.0.js"></script>
<script src="~/signalr/hubs"></script>

<script>
    var logArea = $("#newLogArea");


    var connection = $.connection("/echo");

    connection.received(function (data) {
        alert(data);
    });

    connection.start().done(function(){
        alert("start");
    }).fail(function (x) {
        alert(x);
    });

</script>

LogWatchConnection.cs

namespace MvcApplication4.SignalR.Sample
{
    public static class GlobalConfig
    {
        public static readonly string LogPath = @"C:\Users\user-pc\Documents\visual studio 2012\Projects\MvcApplication4\MvcApplication4\bin\log.txt";
    }

    public class LogWatchConnection : PersistentConnection
    {
        StreamReader reader;


        protected override Task OnConnected(IRequest request, string connectionId)
        {
            InitializeWatcher();
            return base.OnConnected(request, connectionId);
        }

        protected override Task OnReconnected(IRequest request, string connectionId)
        {
            InitializeWatcher();
            return base.OnReconnected(request, connectionId);
        }

        void InitializeWatcher()
        {
            if (reader != null) return;

            var stream = new FileStream(GlobalConfig.LogPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
            stream.Seek(0, SeekOrigin.End); // set to end
            this.reader = new StreamReader(stream, Encoding.UTF8);

            var fsw = new FileSystemWatcher(Path.GetDirectoryName(GlobalConfig.LogPath), Path.GetFileName(GlobalConfig.LogPath));
            fsw.EnableRaisingEvents = true;
            fsw.Changed += fsw_Changed;
        }

        void fsw_Changed(object sender, FileSystemEventArgs e)
        {
            var str = reader.ReadToEnd();
            if (string.IsNullOrWhiteSpace(str)) return;

            Connection.Broadcast(str);
        }
    }
}

RouteConfig.cs

namespace MvcApplication4
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapConnection<LogWatchConnection>("echo", "/echo");

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
            );
        }
    }
}