Asp net SignalR 实现服务端消息推送到Web端.docx

A SignalR 实现服务端消息推送到Web端
          之前的文章介绍过A SignalR,  ASP .NET SignalR是一个ASP .NET 下的类库，可以在ASP .NET 的Web项目中实现实时通信.  今天我们来实现服务端消息推送到Web端,   首先回顾一下它抽象层次图是这样的:

实际上 A SignalR 2 实现 服务端消息推送到Web端, 更加简单. 为了获取更好的可伸缩性, 我们引入消息队列, 看如下基本流程图:

消息队列MQ监听, 在Web site 服务端一收到消息,马上通过Signalr 推送广播到客户端.  创建ASP.NET MVC WEB APP,  从NuGet 安装SignalR 2.12
Install-Package Microsoft.AspNet.SignalR
具体实现代码,是这样的,我们增加一个空的Hub:
public class FeedHub : Hub
{
public void Init()
{
}
}

是简单的消息模型, 标题与正文属性: 
[Serializable]
public class PushMessageModel
{
public int Id { get; set; }
public string MSG_TITLE { get; set; }
public string MSG_CONTENT { get; set; }
}
服务端推送具体类,记录日志, 创建消息队列实例,监听, 等待收取消息. 这里我们使用的是AcitveMQ的.net客户端. ActiveMQListenAdapter是一个封装过的对象. 
public class MQHubsConfig
{
private static ILogger log = new Logger("MQHubsConfig");

/// <summary>
/// Registers the mq listen and hubs.
/// </summary>
public static void RegisterMQListenAndHubs()
{
var activemq = Megadotnet.MessageMQ.Adapter.ActiveMQListenAdapter<PushMessageModel>.Instance(MQConfig.MQIpAddress, MQConfig.QueueDestination);
activemq.MQListener += m =>
{
log.InfoFormat("从MQ收到消息{0}", m.MSG_CONTENT);
GlobalHost.ConnectionManager.GetHubContext<FeedHub>().Clients.All.receive(m);
};

activemq.ReceviceListener<PushMessageModel>();
}
}

上面有一句关键代码GlobalHost.ConnectionManager.GetHubContext<FeedHub>().Clients.All.receive(m);  这里使用了GetHubContext方法后,直接来广播消息.
需要在MVCApplication下加载:
public class MvcApplication : System.Web.HttpApplication
{
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
MQHubsConfig.RegisterMQListenAndHubs();
}
}

同时需要增加一个Starup.cs, 用于Owin
[assembly: OwinStartup(typeof(RealTimeApp.Startup))]
namespace RealTimeApp
{
public class Startup
{
public void Configuration(IAppBuilder app)
{
// Any connection or hub wire up and configuration should go here
app.MapSignalR();
}
}
}
接下来是客户端App.js:
function App() {
var init = function () {
Feed();
$.connection.hub.logging = true;
$.connection.hub.start()
.done(function() {
console.log("Connected!");
$(document).trigger("Connected");
})
.fail(function() { console.log("Could not Connect!"); });
};

init();
};
Feed.js 具体与SignalR.js通信, 创建名为receive的function, 与服务端对应
function Feed() {
var chat = undefined;

var init = function () {

// Reference the auto-generated proxy for the hub.
chat = $.connection.feedHub;
// Create a function that the hub can call back to display messages.
chat.client.receive = function (item) {
var selector = "ul.feed-list li[data-id=" + item.Id + "]";
if (!($(selector).length > 0)) {
$("ul.feed-list").prepend($(".feed-template").render(item));
$("ul.feed-list li:gt(3)").remove();
}

$.messager.show({
title: 'Tips',
msg: item.MSG_CONTENT,
showType: 'show'
});

};

// Start the connection.
$.connection.hub.start().done(function () {
chat.server.init();
});

};

init();
};
        上面的javascript代码与服务端有通信, 具体看如下图:

        在Index.cshtml,  我们需要引用SignalR客户端JS, 放置hubs, 这里我们使用了jsrender,  easyui.js 来呈现推送的消息.
@model dynamic

@section Scripts {
<link href="/Content/themes/default/window.css" rel="stylesheet" />
<link href="~/Content/themes/default/progressbar.css" rel="stylesheet" />
<link href="~/Content/themes/default/linkbutton.css" rel="stylesheet" />
<script src="~/Scripts/jquery.signalR-2.1.2.min.js"></script>
<!--Reference the autogenerated SignalR hub script. -->
<script src="~/signalr/hubs"></script>

<script src="~/Scripts/jsrender.js"></script>
<script src="~/Scripts/jquery.easyui.min-1.4.1.js"></script>

@Scripts.Render("~/Scripts/project.js")

<script type="text/javascript">
$(document).ready(function () {
var app = new App();
});

</script>
}

<div class="row-fluid">

<div class="span8">
<div class="widget">
<div class="widget-header">
<h2>Feed</h2>
</div>
<div class="widget-content">
<ul class="span12 feed-list"></ul>
</div>
</div>
</div>
</div>

<script class="chat-template" type="text/x-jquery-tmpl">
<li>
<p>{{>Message}}</p>
</li>
</script>

<script class="feed-template" type="text/x-jquery-tmpl">
<li data-id="{{>Id}}">
<div class="row-fluid">

<div class="span8">
<h3>{{>MSG_CONTENT}}</h3>
</div>
</div>
</li>
</script>
上代码服务端引用js的Script.Render, 需要在BundleConfig.cs中加入以下代码:
bundles.Add(new ScriptBundle("~/Scripts/project.js")
.IncludeDirectory("~/Scripts/Project", "*.js", false));
同时我们构建一个WebAPI来发送需要推送的消息, 片断代码:
/// <summary>
/// SendMessage
/// </summary>
/// <param name="messagemodel">The messagemodel.</param>
/// <returns></returns>
[HttpPost]
public IHttpActionResult SendMessage(PushMessageModel messagemodel)
{
return SendToServer(messagemodel);

}

/// <summary>
/// Sends to server.
/// </summary>
/// <param name="messagemodel">The messagemodel.</param>
/// <returns></returns>
private IHttpActionResult SendToServer(PushMessageModel messagemodel)
{

if (ModelState.IsValid)
{
if (messageRepository.SendMessage(messagemodel))
{
log.Debug("发送成功！");
return Ok();
}
else
{
log.ErrorFormat("发送失败！{0}", messagemodel);
return Content(HttpStatusCode.ExpectationFailed, new Exception("send message error"));
}
}
else
{
log.ErrorFormat("参数验证失败！{0}", messagemodel);
return Content(HttpStatusCode.BadRequest, ModelState);
}

}

发送消息到ActiveMQ的关键代码:
public class MessageRepository:IMessageRepository
{
private static ILogger log = new Logger("MessageRepository");

/// <summary>
/// 发送消息
/// </summary>
/// <param name="messagemodel"></param>
/// <returns></returns>
public bool SendMessage(PushMessageModel messagemodel)
{
var activemq = new ActiveMQAdapter<PushMessageModel>(MQConfig.MQIpAddress, MQConfig.QueueDestination);
return activemq.SendMessage<PushMessageModel>(messagemodel)>0;
}
}

如果您需要运行DEMO程序,需要构建基于ActiveMQ的消息队列,   运行效果是这样的, 我们在一个静态html中, 发送一个ajax到webapi服务端,  发送后

另一个website网站收到后, 列表更新, 并在右下角弹出框

IE的控制台输出:
HTML1300: Navigation occurred. 
File: Index 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: Client subscribed to hub 'feedhub'. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: Negotiating with '/signalr/negotiate?clientProtocol=1.4&connectionData=%5B%7B%22name%22%3A%22feedhub%22%7D%5D'. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: This browser doesn't support SSE. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: Binding to iframe's load event. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: Iframe transport started. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: foreverFrame transport selected. Initiating start request. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: The start request succeeded. Transitioning to the connected state. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: Now monitoring keep alive with a warning timeout of 13333.333333333332 and a connection lost timeout of 20000. 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: Invoking feedhub.Init 
Connected! 
[11:05:25 GMT+0800 (China Standard Time)] SignalR: Invoked feedhub.Init 
[11:07:12 GMT+0800 (China Standard Time)] SignalR: Triggering client hub event 'receive' on hub 'FeedHub'. 
[11:07:18 GMT+0800 (China Standard Time)] SignalR: Triggering client hub event 'receive' on hub 'FeedHub'. 
[11:07:32 GMT+0800 (China Standard Time)] SignalR: Triggering client hub event 'receive' on hub 'FeedHub'. 
[11:07:51 GMT+0800 (China Standard Time)] SignalR: Triggering client hub event 'receive' on hub 'FeedHub'. 
[11:09:25 GMT+0800 (China Standard Time)] SignalR: Triggering client hub event 'receive' on hub 'FeedHub'.
上面粗体是 最后我们发的第5条信息控制台的输出.