<?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;
?>