<?php
// Connect to Redis
$redis = new Redis();
$redis->connect('127.0.0.1', 6379);

// Get the client IP
$clientIp = $_SERVER['REMOTE_ADDR'];

// Normalize IPv6 addresses to /64 (for IPv6, split by ':' and join the first 4 parts)
if (strpos($clientIp, ':') !== false) {
    $parts = explode(':', $clientIp);
    // Ensure we have at least 4 parts; adjust if needed based on your IPv6 formatting
    $clientIp = implode(':', array_slice($parts, 0, 4));
}

$limit = 100;         // Maximum allowed requests
$timeWindow = 60;     // Time window in seconds

$key = "rate_limit:{$clientIp}";

// Atomically increment the counter
$count = $redis->incr($key);
if ($count == 1) {
    // Set the expiration for the first hit in the window
    $redis->expire($key, $timeWindow);
}

// Check if the limit has been exceeded
if ($count > $limit) {
    header("HTTP/1.1 429 Too Many Requests");
    echo "Too many requests. Please try again later.";
    exit;
}

// Proceed with the rest of your application logic...
?>