SSE:服务器发送事件,使用长链接进行通讯 基础学习

HTML5中新加了EventSounce对象,实现即时推送功能,可以从下面连接中学习,

 

http://www.kwstu.com/ArticleView/kwstu_201408290647460932

 

http://www.cnblogs.com/goody9807/p/4257192.html

 

http://www.cnblogs.com/winhu/p/3435262.html?utm_source=tuicool&utm_medium=referral

 

但最后发现,这种号称由服务器主动推送也不完全准确,比如:

 var es = new EventSource("/Home/GetDate");
    es.onopen = function (e) {
        document.getElementById("state").innerHTML=("正在连接....")
    }
    es.onmessage = function (e) {
        document.getElementById("state").innerHTML=("已连接")

        $("#msg").append(e.data);
    };

    es.addEventListener('myevent', function (e) {
        document.getElementById("state").innerHTML=("出错???? ");

        console.log(e.data);
    });
    $(function () {
        $("#btn").click(function () {
            $.post("/Home/Set", null, function (date) {
                alert(date);
            });
        });
    })
    script>head>
<body>
    <button id="btn">改变值button>
    <div>
        状态:<div id="state">div>
        消息:<div id="msg">div>
    div>

body>
     public string value { get; set; }
public void GetDate() { try { var data = GetData(); HttpContext.Response.ContentType = "text/event-stream"; HttpContext.Response.CacheControl = "no-cache"; HttpContext.Response.Write("data:" + data + "\n\n"); HttpContext.Response.Flush(); Thread.Sleep(1000); } catch (Exception) { } } private object GetData() { return this.value; } public ActionResult Set() { Random r = new Random(); this.value = r.Next(30)+""; return Content("ok"); }


上面实际运行时,每隔几秒客户端浏览器就会向服务器发出连接,就会把服务器value值返回到网页上,其实value值没有发生变化,一般不变的情况我们是不需要在网页中显示的,也就是不做处理,但每次隔几秒就连接服务器会不会消耗资源,带来浪费,这种好像也不是服务器主动推送数据吧,如果对GetDate函数做一改动,如下,增加while循环就成了长轮训了,长时间与客户端保持连接,但从客户端改变value值总是不成功,可能是能力不够,但到现在我也没想出好办法,HTML5的EventSource到底是如何使用还需要时间研究.....

 public void GetDate()
        {
            try
            {
                
                HttpContext.Response.ContentType = "text/event-stream";
                HttpContext.Response.CacheControl = "no-cache";

                while (true)
                {
                    var data = GetData();
                    HttpContext.Response.Write("data:" + data + "\n\n");
                    HttpContext.Response.Flush();
                    Thread.Sleep(1000);
                }
            }
            catch (Exception)
            {
            }
        }

 

转载于:https://www.cnblogs.com/lunawzh/p/4920152.html

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