__unserialize() Method

The __unserialize() magic method is called when a script tries to construct an object from an associative array of key/value pairs.

<?php

    class X {
        private $html;
        private $url;

        public function __construct($url) {
            $this->url = $url;
        }

        public function __serialize() {
            return ['url' => $url];
        }

        public function __unserialize($arg) {
            $this->url = $arg['url'];
            $this->html = file_get_contents($this->url);
        }

    }

?>

Documentation

Related : Unserialization, Serialization, __serialize() Method, Insecure Deserialization, Serialization