Lazy Request

lazy_request.php

<?php

abstract class Lazy implements \ArrayAccess {
    private $input;
    private $cache = array();

    public function __construct($input) {
        static $inputs = array(
            INPUT_POST, INPUT_GET, INPUT_COOKIE,
            INPUT_ENV, INPUT_SERVER, INPUT_SESSION
        );

        if (!in_array($input, $inputs)) {
            throw new \InvalidArgumentException('Invalid input');
        }

        $this->input = $input;
    }

    public function offsetExists($offset) {
        if (array_key_exists($offset, $this->cache)) {
            return true;
        }

        return filter_has_var($this->input, $this->transformName($offset));
    }

    public function offsetGet($offset) {
        if (array_key_exists($offset, $this->cache)) {
            return $this->cache[$offset];
        }

        $value = filter_input($this->input, $this->transformName($offset));

        if (false === $value) {
            throw new \LogicException('Error');
        }

        return $this->cache[$offset] = $this->transformValue($offset, $value);
    }

    public function offsetSet($offset, $value) {}

    public function offsetUnset($offset) {}

    protected function transformName($name) { return $name; }
    protected function transformValue($name, $value) { return $value; }
}

class Query extends Lazy {
    public function __construct() {
        parent::__construct(INPUT_GET);
    }
}

class Form extends Lazy {
    public function __construct() {
        parent::__construct(INPUT_POST);
    }
}

class Headers extends Lazy {
    static $headers = array(
        'Accept' => 'Header',
        'Accept-Charset' => 'Header',
        'Accept-Language' => 'Header',
        'Accept-Encoding' => 'Header',

        'Connection' => 'Header',
        'Cookie' => 'Header',

        'Host' => 'Header',
        'Referer' => 'Header',
        'User-Agent' => 'Header',

        'Content-Type' => 'Header',
        'Content-Length' => 'Header',
    );

    public function __construct() {
        parent::__construct(INPUT_SERVER);
    }

    protected function transformName($name) {
        if (!array_key_exists($name, self::$headers)) {
            throw new \InvalidArgumentException('Invalid header');
        }

        if (strpos($name, 'Content-') === 0) {
            $key = substr($name, 8);
            $key = 'CONTENT_' . strtoupper($key);
        } else {
            $key = 'HTTP_' . strtoupper(strtr($name, '-', '_'));
        }

        return $key;
    }

    protected function transformValue($name, $value) {
        if (!array_key_exists($name, self::$headers)) {
            throw new \InvalidArgumentException('Invalid header');
        }

        $class = self::$headers[$name];
        $instance = new $class($name, $value);

        return $instance;
    }
}

class Header {
    public $name;
    public $value;

    public function __construct($name, $value) {
        $this->name = $name;
        $this->value = $value;
    }
}

class Request {
    protected $query;
    protected $form;
    protected $headers;

    public function __construct(Query $query, Form $form, Headers $headers) {
        $this->query = $query;
        $this->form = $form;
        $this->headers = $headers;
    }

    public function __get($key) {
        return $this->$key;
    }
}