Unique Hit Counter

<?php
// Before using:
// Create a directory to store hits and set its permissions to 777
// To use:
/* <?php include "include.unique_hit_counter.php"; ?> */

// File path for storing hits data
$file_path = '/files/';
// Build filename
$counter_file = getcwd().$file_path.md5($_SERVER['SCRIPT_NAME']).".txt";
// Get data to be stored
$user_ip = $_SERVER['REMOTE_ADDR'];
$ctime = time();
// Build storage variables
$ip_array  = array();
$count = 0;
// If data file exists extract hits
if(file_exists($counter_file)) {
    $content = file_get_contents($counter_file);
    $info = unserialize($content);
    
    $count = count($info);
    
    foreach($info as $entry) {
        list($ip, $time) = $entry;
        $ip_array[] = $ip;
    } 
}
// Verify that the visitor is new
$unique = !in_array($user_ip, $ip_array);
// If the visitor is unique, add their hit to the data file
if($unique) {
    $ip_array[] = $user_ip;
    $info[] = array($user_ip, $ctime);
    
    $count++;

    $file = fopen($counter_file, 'w');
    fwrite($file, serialize($info));
    fclose($file);
}
// Echo the hit count
echo $count;
?>

// This line will output the number of unique hits
include "include.unique_hit_counter.php";