php实现统计网站在线人数的方法

<?php function getIpAddress() { // 取得当前用户的IP地址 if (getenv('HTTP_CLIENT_IP')) { $ip = getenv('HTTP_CLIENT_IP'); } elseif (getenv('HTTP_X_FORWARDED_FOR')) { $ip = getenv('HTTP_X_FORWARDED_FOR'); } elseif (getenv('REMOTE_ADDR')) { $ip = getenv('REMOTE_ADDR'); } else { $ip = $_SERVER['REMOE_ADDR']; } return $ip; } function writeover($filename,$data,$method = 'w',$chmod = 0){ $handle = fopen($filename, $method); !handle && die("文件打开失败"); flock($handle, LOCK_EX); fwrite($handle, $data); flock($handle, LOCK_UN); fclose($handle); $chmod && @chmod($filename, 0777); } function count_online_num($time, $ip) { $fileCount = './count.txt'; $count = 0; $gap = 900; //15分钟不刷新页面就 if (!file_exists($fileCount)) { $str = $time . "\t" . $ip . "\r\n"; writeover($fileCount, $str, 'w', 1); $count = 1; } else { $arr = file($fileCount); $flag = 0; foreach($arr as $key => $val) { $val= trim($val); if ($val != "") { list($when, $seti) = explode("\t", $val); if ($seti ==$ip) { $arr[$key] = $time . "\t" . $seti; $flag = 1; } else { $currentTime = time(); if ($currentTime - $when > 900) { unset($arr[$key]); }else{ $arr[$key]=$val; } } } } if ($flag == 0) { array_push($arr, $time . "\t" . $ip); } $count = count($arr); $str = implode("\r\n", $arr); $str.="\r\n"; writeover($fileCount, $str, 'w', 0); unset($arr); } return $count; } $time = time(); $ip = getIpAddress(); $online_num = count_online_num($time,$ip); echo $online_num; ?>