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php实现实时通信一般有两种方式:socket或comet。socket是比较好的解决方案,问题在于不是所有的浏览器都兼容,服务器端实现起来也稍微有点麻烦。
<?php // NovComet.php class NovComet { const COMET_OK = 0; const COMET_CHANGED = 1; private $_tries; private $_var; private $_sleep; private $_ids = array(); private $_callback = null; public function __construct($tries = 20, $sleep = 2) { $this->_tries = $tries; $this->_sleep = $sleep; } public function setVar($key, $value) { $this->_vars[$key] = $value; } public function setTries($tries) { $this->_tries = $tries; } public function setSleepTime($sleep) { $this->_sleep = $sleep; } public function setCallbackCheck($callback) { $this->_callback = $callback; } const DEFAULT_COMET_PATH = "/dev/shm/%s.comet"; public function run() { if (is_null($this->_callback)) { $defaultCometPAth = self::DEFAULT_COMET_PATH; $callback = function($id) use ($defaultCometPAth) { $cometFile = sprintf($defaultCometPAth, $id); return (is_file($cometFile)) ? filemtime($cometFile) : 0; }; } else { $callback = $this->_callback; } for ($i = 0; $i < $this->_tries; $i++) { foreach ($this->_vars as $id => $timestamp) { if ((integer) $timestamp == 0) { $timestamp = time(); } $fileTimestamp = $callback($id); if ($fileTimestamp > $timestamp) { $out[$id] = $fileTimestamp; } clearstatcache(); } if (count($out) > 0) { return json_encode(array(‘s‘ => self::COMET_CHANGED, ‘k‘ => $out)); } sleep($this->_sleep); } return json_encode(array(‘s‘ => self::COMET_OK)); } public function publish($id) { return json_encode(touch(sprintf(self::DEFAULT_COMET_PATH, $id))); } } <?php // comet.php include(‘NovComet.php‘); $comet = new NovComet(); $publish = filter_input(INPUT_GET, ‘publish‘, FILTER_SANITIZE_STRING); if ($publish != ‘‘) { echo $comet->publish($publish); } else { foreach (filter_var_array($_GET[‘subscribed‘], FILTER_SANITIZE_NUMBER_INT) as $key => $value) { $comet->setVar($key, $value); } echo $comet->run(); } function send(msg){ $.ajax({ data : {‘msg‘ : msg}, type : ‘post‘, url : ‘{:U(‘Live/SendMsg‘)}‘, success : function(response){ //alert(response);; } }) } $(document).ready(function(){ connect(); $("#btn").click(function(){ var msg = $(‘#msg‘).val(); send(msg); msg.html(‘‘); }); }) public function SendMsg(){ $filename = ‘./Uploads/live/‘.‘data.json‘; if ($_POST[‘msg‘]!=‘‘) { file_put_contents($filename,$_POST[‘msg‘]); $this->ajaxReturn($_POST,‘OK‘,100); die(); }else{ $this->ajaxReturn($_POST,‘on‘,0); die(); } } <!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-1.8.2.min.js"></script> <script type="text/javascript" src="./json2.js"></script> <script> var timestamp = 0; var url = ‘backend.php‘; var error = false; // 通过ajax建立和php端处理函数的连接(通过递归调用建立长时间的连接) function connect(){ $.ajax({ data : {‘timestamp‘ : timestamp}, url : url, type : ‘get‘, timeout : 0, success : function(response){ var data = JSON.parse(response); error = false; timestamp = data.timestamp; if (data.msg != undefined && data.msg != "") { $("#content").append("<div>" + data.msg + "</div>"); } }, error : function(){ error = true; setTimeout(function(){ connect();}, 5000); }, complete : function(){ if (error) // 请求有错误时,延迟5s再连接 setTimeout(function(){connect();}, 5000); else connect(); } }) } // 发送信息 function send(msg){ $.ajax({ data : {‘msg‘ : msg}, type : ‘get‘, url : url }) } // 创建长时间的连接 $(document).ready(function(){ connect(); }) </script> </head> <body> <div id="content"></div> <form action="" method="get" onsubmit="send($(‘#word‘).val());$(‘#word‘).val(‘‘);return false;"> <input type="text" name="word" id="word" value="" /> <input type="submit" name="submit" value="Send" /> </form> </body> </html> <?php // 设置请求运行时间不限制，解决因为超过服务器运行时间而结束请求 ini_set("max_execution_time", "0"); $filename = dirname(__FILE__).‘/data.txt‘; $msg = isset($_GET[‘msg‘]) ? $_GET[‘msg‘] : ‘‘; // 判断页面提交过来的修改内容是否为空，不为空则将内容写入文件，并中断流程 if ($msg != ‘‘) { file_put_contents($filename,$msg); exit; } /* 获取文件上次修改时间戳 和 当前获取到的最近一次文件修改时间戳 * 文件上次修改时间戳 初始 默认值为0 * 最近一次文件修改时间戳 通过 函数 filemtime()获取 */ $lastmodif = isset($_GET[‘timestamp‘]) ? $_GET[‘timestamp‘] : 0; clearstatcache(); // 清除文件状态缓存 $currentmodif = filemtime($filename); /* 如果当前返回的文件修改unix时间戳小于或等于上次的修改时间， * 表明文件没有更新不需要推送消息 * 如果当前返回的文件修改unix时间戳大于上次的修改时间 * 表明文件有更新需要输出修改的内容作为推送消息 */ while ($currentmodif <= $lastmodif) { usleep(10000); // 休眠10ms释放cpu的占用 clearstatcache(); // 清除文件状态缓存 $currentmodif = filemtime($filename); } // 推送信息处理(需要推送说明文件有更改，推送信息包含本次修改时间、内容) $response = array(); $response[‘msg‘] = file_get_contents($filename); $response[‘timestamp‘] = $currentmodif; echo json_encode($response); flush(); ?>
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原文地址：http://www.cnblogs.com/520fyl/p/5396310.html
