Automatically updating a hosts file for dynamic dns

update.php

<?php

if(!isset($_SERVER['HTTPS']) || $_SERVER['HTTPS'] == ""){
    $redirect = "https://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI'];
    header("Location: $redirect");
}

class Host {
    private $ip;
    private $hosts;

    public function __construct($ip = '', $hostname = null) {
        $this->ip = $ip;
        $this->hosts = array();
        if($hostname) $this->hosts[] = $hostname;
    }
    
    public function setIP($ip) {
    	$this->ip = $ip;
    }

    public function getHosts() {
        return $this->hosts;
    }
    
    public static function fromLine($line) {
        $line = trim($line);

        if(empty($line) || false !== strpos($line, '#')) return false;
        
        $host = new Host();
        
        $columns = preg_split('/\h+/', $line);
        $host->ip = array_shift($columns);
        $host->hosts = array_filter($columns, function($element) {
            return trim($element) != "";
        });

        return $host;
    }

    public static function fromFile($file) {
        $hosts = array();

        $handle = @fopen($file, "r");
        if ($handle) {
            while (($buffer = fgets($handle, 4096)) !== false) {
                if(false !== $host = Host::fromLine($buffer)) $hosts[] = $host;
            }
            if (!feof($handle)) {
                throw new Exception("Error: unexpected fgets() fail");
            }
            fclose($handle);
        }
        return $hosts;
    }

    public function __toString() {
        if(!is_array($this->hosts)) die(print_r($this,1));
        return $this->ip . "\t" . implode(' ', $this->hosts);
    }
        
    public static function toString($hosts) {
        $fileContent = "";

        foreach($hosts as $host) {
            $fileContent .= "$host\n";
        }
                
        return $fileContent;
    }
    
    public static function toFile($file, $hosts) {
        file_put_contents($file, Host::toString($hosts));
    }
    
    public static function array_search($hosts, $hostname) {
        foreach($hosts as $index => $host) {
            if(false !== array_search($hostname, $host->getHosts())) {
                return $index;
            }
        }
        return false;
    }
}

function getRealIpAddr() {
  if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
    $ip=$_SERVER['HTTP_CLIENT_IP'];
  } elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
    $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
  } else {
    $ip=$_SERVER['REMOTE_ADDR'];
  }
  return $ip;
}

$hosts = Host::fromFile('/etc/hosts');

$hostname = $_POST['hostname'];
$ip = getRealIpAddr();

if(!$hostname) throw new Exception("Bad request");

$index = Host::array_search($hosts, $hostname);
if(false !== $index) {
    $host = $hosts[$index];
    $host->setIP($ip);
    system('/home/pablo/dnsmasq_restart');
}

Host::toFile('/etc/hosts', $hosts);