Jquery+php实现comet

最新推荐文章于 2024-05-19 09:49:05 发布

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本文介绍了一个基于Comet技术实现的简单示例，通过客户端与服务器的长轮询交互，实现消息的实时推送功能。该示例使用了jQuery进行Ajax请求，并以PHP作为服务器端语言。

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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
<title>Comet demo</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript" src="jquery.min.js"></script>
<script>
var timestamp = 0;
var url = './test.php';
var error = false;
function connect(){
      $.ajax({
         data : {'timestamp' : timestamp},
         url : url,
         type : 'get',
         timeout : 0,
         success : function(response){
            var data = eval('('+response+')');
            error = false;
            timestamp = data.timestamp;
            $("#content").append('<div>' + data.msg +'</div>');
         },
         error : function(){
            error = true;
            setTimeout(function(){ connect();}, 5000);
         },
         complete : function(){
            if (error)
                  // if a connection problem occurs, try to reconnect each 5 seconds
                  setTimeout(function(){connect();}, 5000);
            else
                  connect();
         }
      })
}
function send(msg){
      $.ajax({
         data : {'msg' : msg},
         type : 'get',
         url : url
      })
}
    function getLocalTime(nS) {
        return new Date(parseInt(nS) * 1000).toLocaleString().replace(/:\d{1,2}$/,' ');
   }
$(document).ready(function(){
      connect();
})
</script>
  </head>
  <body>

  <div id="content">
  </div>

  <p>
<form action="" method="get" onsubmit="send($('#word').val());$('#word').val('');return false;">
   <input type="text" name="word" id="word" value="" />
   <input type="submit" name="submit" value="Send" />
</form>
  </p>

  </body>

</html>

test.php

<?php
$filename = dirname(__FILE__).'/data.txt';

// store new message in the file
$msg = isset($_GET['msg']) ? $_GET['msg'] : '';
if ($msg != '')
{
file_put_contents($filename,$msg);
die();
}

// infinite loop until the data file is not modified
$lastmodif = isset($_GET['timestamp']) ? $_GET['timestamp'] : 0;
$currentmodif = filemtime($filename);
while ($currentmodif <= $lastmodif) // check if the data file has been modified
{
usleep(10000); // sleep 10ms to unload the CPU
clearstatcache();
$currentmodif = filemtime($filename);
}

// return a json array
$response = array();
$response['msg'] = file_get_contents($filename);
$response['timestamp'] = $currentmodif;
echo json_encode($response);
flush();
?>