Wohoo. Templates and Cache :)

Cache.php

<?php

class Cache {
  
  protected $_scope;
  
  public function __construct($scope = null, $lifetime = 3600) {    
    if (null === $scope) $scope = sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'mikeCache_' . md5(__FILE__) . DIRECTORY_SEPARATOR;
    if (!is_dir($scope)) mkdir($scope, 0777, true);
    
    $this->_scope = rtrim($scope, DIRECTORY_SEPARATOR);
    $this->_lifetime = $lifetime;
  }
  
  protected function _isValidKey($key) {
    if (false !== strpos($key, "\\") || false !== strpos($key, "/")) {
      throw new Exception('Who do you want to hack?');
      return false;
    }
    
    return true;
  }
  
  public function __set($key, $content) {
    if ($this->_isValidKey($key)) \file_put_contents($this->_scope . DIRECTORY_SEPARATOR . $key, serialize($content));
  }
  
  public function __get($key) {
    $filename = $this->_scope . DIRECTORY_SEPARATOR . $key;
    
    if (!$this->_isValidKey($key)) || !file_exists($filename) || filectime($filename) + $this->_lifetime < time()) return null;
    
    return unserialize(\file_get_contents($filename));
  }

}

example.php

<?php

// oh no a visitor... do I have to do something?
$cache = new Cache();

if (!$cache->welcome)
{ // yes i have to -.-
  $welcome = new View('welcome.phtml', ['name' => 'Tom']);
  $cache->welcome = $welcome;
}

$cache->welcome->dispatch();

View.php

<?php

class View extends \ArrayObject {
  
  protected $_fileName;
  
  public function __construct($fileName, $data = array())
  {
    if (!stream_resolve_include_path($fileName)) throw new \ArgumentException("File $fileName not found.");
    
    $this->_fileName = $fileName;
    parent::__construct((array) $data);
  }
  
  public function getFileName() {
    return $this->_fileName;
  }
  
  public function __toString() {
    ob_start();
    $this->dispatch();
    return ob_get_clean();
  }
  
  public function dispatch() {
    extract($this->getArrayCopy());
    include $this->getFileName();
  }
}