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一般需求推送服务时,都会去第三方拿推送组件,如”极光“,”百度“,”小米"什么的,自己用.net实现推送服务端需要面对很多问题,比如C10K,但是企业内部使用往往用不了10K的链接,有个1K,2K就足够,这个时候完全可以自己实现一个推送服务,这样手机应用就不用走外网了。
使用.net实现推送服务有几个选择
1.是使用WCF 基于TCP的回调-针对.net To .net 端,经过7*24小时测试,2K左右的链接能稳定hold住,参考:http://www.cnblogs.com/wdfrog/p/3924718.html
2.自己使用TcpListener或Socket实现一个长连击服务器,由于推送的信息都很短(长信息只推送信息编号),这样在一个MTU里面就可以完成传输,整体上实现起来也不麻烦 ,最近也做了个,大概加一起就400百来行代码,2K链接已经(实际只要hold住98个用户就好了)稳定运行了6天了。
3.使用Comet Request, 首先Comet Request 采用Asp.net + IIS,整整网页就好了,另外由于IIS应用程序池会定期回收,程序写的烂点也不影响,每天都给你一个新的开始,还有Comet 的实现网上代码很多,还有开源的SignalR可以用.
采用Comet方式的实现
1.服务端,使用IHttpAsyncHandler来Hold住请求,需要根据cookie或QueryString中带的UserId来区分不同的用户
using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace MangoPush.WebComet.Core { public class PushAsyncHandle : IHttpAsyncHandler { public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData) { var ar = new PushAsyncResult(context, cb, extraData); CometRequestMgr.Instance.Add(ar); return ar; } public void EndProcessRequest(IAsyncResult result) { } public bool IsReusable { get { return true; } } public void ProcessRequest(HttpContext context) { throw new NotImplementedException(); } } }
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Threading; namespace MangoPush.WebComet.Core { public class PushAsyncResult:IAsyncResult { private static int GId = 0; private bool m_IsCompleted = false; private AsyncCallback Callback = null; public HttpContext Context; private Object _AsyncState; public DateTime AddTime{get;private set;} public int Id { get; set; } public PushAsyncResult(HttpContext context, AsyncCallback callback, object asyncState) { Context = context; Callback = callback; _AsyncState = asyncState; AddTime = DateTime.Now; Interlocked.Increment(ref GId); int userId = int.TryParse(Context.Request["UserId"], out userId) ? userId : 0; Id = userId; if (userId == 0) { Release(JUtil.ToJson(new {Code=-1,Msg="未提供UserId" })); } } public void Release(string msg) { try { try { Context.Response.Write(msg); } catch { } if (Callback != null) { Callback(this); } } catch { } finally { m_IsCompleted = true; } } public object AsyncState { get { return _AsyncState; } } public System.Threading.WaitHandle AsyncWaitHandle { get { return null; } } public bool CompletedSynchronously { get { return false; } } public bool IsCompleted { get { return m_IsCompleted; } } } }
using System; using System.Collections.Generic; using System.Collections.Concurrent; using System.Linq; using System.Web; namespace MangoPush.WebComet.Core { public class CometRequestMgr { public static readonly CometRequestMgr Instance = new CometRequestMgr(); private ConcurrentDictionary<int, PushAsyncResult> Queue = new ConcurrentDictionary<int, PushAsyncResult>(); private CometRequestMgr() { var timer = new System.Timers.Timer(); timer.Interval = 1000 * 30; timer.AutoReset = false; timer.Elapsed += (s, e) => { try { var list = Queue.Select(ent => ent.Value).ToList(); #region 清理完成链接 foreach (var it in list) { if (it.IsCompleted) { try { PushAsyncResult c = null; Queue.TryRemove(it.Id,out c); } catch (Exception ex) { continue; } } } #endregion } catch (Exception ex) { } finally { timer.Start(); } }; timer.Start(); } public void Add(PushAsyncResult ar) { Queue[ar.Id] = ar; } public void BroadCastMsg(string msg) { msg +="," + DateTime.Now.ToString(); foreach (var c in Queue) { try { c.Value.Release(JUtil.ToJson( new {Code=0,Msg= msg})); } catch { } finally { PushAsyncResult outIt=null; Queue.TryRemove(c.Key,out outIt); } } } } }
2.网页端,使用ajax方式发起访问,特别注意的是需要设置timeout,这样如果断线或者服务端挂了重启,可以自动修复
$(function () { function long_polling() { var _url = ‘/pushService.act?userId=‘ + $("#userId").val(); console.log(_url); var ajaxRequest = $.ajax({ url: _url, //请求的URL timeout: 1000 * 60 * 3, //超时时间设置,单位毫秒 type: ‘get‘, //请求方式,get或post data: {}, //请求所传参数,json格式 dataType: ‘json‘, //返回的数据格式 success: function (data) { //请求成功的回调函数 console.log(data); if (data.Code == 0) { $(‘#msg‘).append(data.Msg + "<br/>"); } }, complete: function (XMLHttpRequest, status) { //请求完成后最终执行参数 if (status == ‘timeout‘) {//超时,status还有success,error等值的情况 ajaxRequest.abort(); console.log("超时"); } if ($("#btn").val() == "停止") { long_polling(); } } }); } $("#btn").click(function () { if ($("#btn").val() == "启动") { long_polling(); $("#btn").val("停止"); } else { $("#btn").val("启动"); } }); $("#btnCls").click(function () { $("#msg").text(""); }); });
3.Winform端,采用WebClient发起请求,并且使用AutoResetEvent控制超时重连(相当于心跳包)
private void Do() { try { while (Enable) { Console.WriteLine("发起请求!"); var url = @"http://192.168.9.6:9866/pushService.act?userId=18"; using (var wc = new WebClient()) { wc.Encoding = Encoding.UTF8; #region 回调处理 wc.DownloadStringCompleted += (s, e) => { if (e.Error != null) { Console.WriteLine(e.Error); } else if (e.Cancelled) { Console.WriteLine("Be Cancelled!"); } else { Console.WriteLine(e.Result); } autoReset.Set(); }; #endregion var uri = new Uri(url); wc.DownloadStringAsync(uri); var isOK= autoReset.WaitOne(1000 * 60 * 5); if (!isOK) { wc.CancelAsync(); } } } } catch (Exception ex) { Console.WriteLine("错误" + ex.Message); } finally { if (Enable) { ThreadPool.QueueUserWorkItem(o => { Do(); }, null); } } }
4.Android端
1.类似WinForm端,目前采用AsyncHttpClient,写法跟Js差不多,需要设置timeout
2.由于android会回收进程,需要AlarmManager,定期检查推送服务是否还存活
3.android系统重启,开关网络,调整时间,需要订阅相应广播,调整AlermManager,触发平率。
总结:
整个能支持10K,100K,2000K链接的,挺不容易,但是一般中小企业使用1K,2K甚至0.1K足矣,3,4百行代码就完事,至少可以让员工不用连3G,4G了,NND,提速降价,也不知道降那去了。
最后整2个图片
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原文地址:http://www.cnblogs.com/wdfrog/p/4600166.html