Using PHP to compare accurate statistics on the number of people online

Using PHP to compare accurate statistics on the number of people online, note that here is the exact number of points, if you need accurate in time, you need to adjust the code in accordance with the actual time of validity. (He didn't write it, took it from someone else, put it in first and then studied it)

<?php
Author:www.scutephp.com
$filename = ' online.txt ';//Data file
$cookiename = ' Vgotcn_onlinecount ';//cookie name
$onlinetime =600;//Online effective time in seconds (i.e. 600 equals 10 minutes)

$online =file ($filename);
The PHP file () function reads the entire file into an array. Like File_get_contents (), the difference is that file () returns files as an array. Each cell in the array is the corresponding line in the file, including the newline character. Returns False if it fails
$nowtime =$_server[' Request_time '];
$nowonline =array ();
Get data that is still valid
foreach ($online as $line) {
$row =explode (' | ', $line);
$sesstime =trim ($row [1]);
if ($nowtime-$sesstime) <= $onlinetime) {//If it is still within the valid time, the data will continue to be saved or discarded no longer counted
$nowonline [$row [0]]= $sesstime;//Get the online list to an array, the session ID is the key name, the last communication time is the key value
}
}
/*
@ Create Visitor Communication status
Use cookies to communicate
The cookie will expire when the browser is closed, but if you do not close the browser, the cookie will remain in effect until the online time of the program setting expires
*/
if (Isset ($_cookie[$cookiename])) {//If a COOKIE is not first accessed, no number of people are added and the communication time is updated
$uid =$_cookie[$cookiename];
}else{//If no cookie is the first visit
$vid =0;//to initialize the visitor ID
do{//give the user a new ID
$vid + +;
$uid = ' U '. $vid;
}while (Array_key_exists ($uid, $nowonline));
Setcookie ($cookiename, $uid);
}
$nowonline [$uid]= $nowtime;//Update the current time state
Statistics now online people
$total _online=count ($nowonline);
Write Data
if ([email protected] ($filename, ' W ')) {
if (Flock ($FP, lock_ex)) {
Rewind ($FP);
foreach ($nowonline as $fuid = = $ftime) {
$fline = $fuid. ' | '. $ftime. " \ n ";
@fputs ($fp, $fline);
}
Flock ($FP, lock_un);
Fclose ($FP);
}
}
Echo ' document.write ('. $total _online. ');

Using PHP to compare accurate statistics on the number of people online