Lazy_PDO.php

<?php

class Lazy_PDO
{
  private $pdo;
  private $dsn, $username, $password, $options;
  
  public function __construct($dsn, $username, $password, $options) {
    $this->dsn = $dsn;
    $this->username = $username;
    $this->password = $password;
    $this->options = $options;
  }
  
  public function openConnection() {
    $this->pdo = new PDO($dsn, $username, $password, $options);
  }
  
  public function closeConnection() {
    unset($this->pdo);
  }
  
  public function __call($func, $args) {
    if ( is_null($this->pdo) ) {
      $this->openConnection();
    }
    
    return call_user_func_array([parent::class, $func], $args);
  }
}