ajax轮询实现长连接

雷亮
2017-08-24 15:36:15
PHP
PHP

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="jquery-1.10.2.min.js"></script>
</head>
<body>
    <div id="msg"></div>
    <input id="btn" type="button" value="测试" />
    <script>
        $(function(){
            $("#btn").bind("click",{btn:$("#btn")},function(evdata){
                $.ajax({
                    type:"POST",
                    dataType:"json",
                    url:"data.php",
                    timeout:80000,  //ajax请求超时时间80秒
                    data:{time:"80"}, //40秒后无论结果服务器都返回数据
                    success:function(data,textStatus){
                        //从服务器得到数据，显示数据并继续查询
                        if(data.success=="1"){
                            $("#msg").append("<br>[有数据]"+data.text);
                            evdata.data.btn.click();
                        }
                        //未从服务器得到数据，继续查询
                        if(data.success=="0"){
                            $("#msg").append("<br>[无数据]");
                            evdata.data.btn.click();
                        }
                    },
                    //Ajax请求超时，继续查询
                    error:function(XMLHttpRequest,textStatus,errorThrown){
                        if(textStatus=="timeout"){
                            $("#msg").append("<br>[超时]");
                            evdata.data.btn.click();
                        }
                    }
                });
            });
        });
    </script>
</body>
</html>

data.php

<?php
if(empty($_POST['time']))exit();
set_time_limit(0);//无限请求超时时间
$i=0;
while (true){
    //sleep(1);
    usleep(500000);//0.5秒
    $i++;
    //若得到数据则马上返回数据给客服端，并结束本次请求
    $rand=rand(1,999);
    if($rand <= 15){
        $arr=array('success'=>"1",'name'=>'xiaocai','text'=>$rand);
        echo json_encode($arr);
        exit();
    }
    //服务器($_POST['time']*0.5)秒后告诉客服端无数据
    if($i==$_POST['time']){
        $arr=array('success'=>"0",'name'=>'xiaocai','text'=>$rand);
        echo json_encode($arr);
        exit();
    }
}

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