Unique Website Visitor Logger

js-hit.php

<?php
const TESTING = false;
const FILE_NAME = ".hits";
const DAYS = 10;
const PASSWORD = "YOUR PASSWORD HERE";

$user_agent = strip_tags($_SERVER['HTTP_USER_AGENT']);
$bots = ["bot", "slurp", "spider", "crawler"];
foreach ($bots as $bot) {
  if (stripos($user_agent, $bot) !== false) exit();
}

$today = date('j');
$log = "";

// Get the data
$data = [
  'today' => $today,
  'records' => []
];

if (is_file(FILE_NAME))
  $data = (array) json_decode(file_get_contents(FILE_NAME));
else
  for($n = 0; $n < DAYS; $n++)
    $data['records'][] = [];

if (isset($_POST["x"]) && $_POST["x"] == PASSWORD)
  exit(json_encode($data));

// Check for new day
if ($data['today'] != $today) {
  $data['today'] = $today;
  for($n = DAYS - 1; $n > 0 ; $n--)
    $data['records'][$n] = $data['records'][$n - 1];
  $data['records'][0] = [];
}

// Log hit
$ip = preg_replace('/[^.:0-9a-z]/', '', $_SERVER['REMOTE_ADDR']);
if (in_array($ip, $data['records'][0]))
  $log = "Existing $ip";
else {
  $data['records'][0][] = $ip;
  $log = "Added $ip";
  file_put_contents(FILE_NAME, json_encode($data));
}

if (TESTING) {
  echo $log;
  print_r($data);
}

The idea of this script is to be able to count the number of unique visitors to a website over the last 10 days independent of 3rd-party tracking tools that can identify sites within your network. It may serve as a tool to judge if a site is worth placing Ads on it etc.

This script is called from a JavaScript snippet that is inserted into the footer of a website template.
<script>(new Image()).src="/js-hit.php?hit"</script>

Or, to disguise the file name, add some PHP script at the beginning of the the index.php file:
if (array_key_exists('hit', $_GET)) { include("js-hit.php"); exit(); }
and the JavaScript snippet is:
<script>(new Image()).src="/?hit"</script>

Also, set up your server to hide the .hits file from browsers.
In NGINX config:
location = /.hits { deny all; return 404; }

To get the hit data, send a POST request with x=YOUR_PASSWORD to the script or get the .hits file via your script/console.

The script creates an array of unique IPv4 addresses for each day. So the visitor count may be deduced from the array sizes. Also, there is a primitive web bot filter applied to try to eliminate web bots that may use JavaScript from the results.

My idea is to create an automated reporting tool that gathers this data from my sites and creates a daily report for me that is saved to my PC.