<?php
/**
 * A concrete HTTP request class to make HTTP requests more abstract
 *
 * @author		Roland Haeder <webmaster@ship-simu.org>
 * @version		0.3.0
 * @copyright	Copyright(c) 2007, 2008 Roland Haeder, this is free software
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.mxchange.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
class HttpRequest extends BaseFrameworkSystem implements Requestable {
	/**
	 * Array for the request data
	 */
	private $requestData = array();

	/**
	 * Protected constructor
	 *
	 * @return	void
	 */
	protected function __construct () {
		// Call parent constructor
		parent::__construct(__CLASS__);

		// Set part description
		$this->setObjectDescription("HTTP-Anfrage");

		// Create unique ID number
		$this->createUniqueID();

		// Clean up a little
		$this->removeNumberFormaters();
		$this->removeSystemArray();
	}

	/**
	 * Creates an instance of this class and prepares it a little
	 *
	 * @return	$httpInstance	An instance of this class
	 */
	public final static function createHttpRequest () {
		// Create an instance
		$httpInstance = new HttpRequest();

		// Prepare the HTTP request data for usage
		$httpInstance->prepareRequestData();

		// Return the prepared instance
		return $httpInstance;
	}

	/**
	 * Prepares the HTTP request data for usage by currently copying
	 * $_REQUEST into a private attribute. Later on we can add more
	 * things for initialization here.
	 *
	 * @return	void
	 */
	public function prepareRequestData () {
		// Copy the $_REQUEST array
		$this->requestData = $_REQUEST;
	}

	/**
	 * Checks wether a request element is set
	 * @param	$element	Name of the request element we want to check
	 * @return	$isSet		Wether the request element is set
	 * @throws	MissingArrayElementsException	Thrown if a request element is not set
	 */
	public function isRequestElementSet ($element) {
		// Is this element found?
		if (!isset($this->requestData[$element])) {
			// Then throw an exception
			throw new MissingArrayElementsException(array($this, 'requestData', $element), self::EXCEPTION_MISSING_ELEMENT);
		}

		// All clear
		return true;
	}

	/**
	 * Getter for request element or 'null' if the element was not found
	 *
	 * @param	$element	Name of the request element we want to check
	 * @return	$value		Value of the found request element or 'null' if the
	 *						element was not found
	 */
	public function getRequestElement ($element) {
		// Initialize value
		$value = null;

		try {
			if ($this->isRequestElementSet($element)) {
				$value = $this->requestData[$element];
			}
		} catch (MissingArrayElementsException $e) {
			// Do nothing here
		}

		// Return the element's value
		return $value;
	}

	/**
	 * Wrapper method for array_key() function for the request data array
	 *
	 * @return	$array	An array containing all array keys to return
	 */
	public function getParameterNames () {
		return array_keys($this->requestData);
	}

	/**
	 * Getter for a header element or 'null' if the header was not found
	 *
	 * @param	$headerName		Name of the header
	 * @return	$headerValue	Value of the header or 'null' if not found
	 */
	public function getHeader ($headerName) {
		// Default return value on error
		$headerValue = null;

		// Construct the name
		$name = 'HTTP_' . strtolower(str_replace('-', '_', $headerName));

		// Does this header exist?
		if (isset($_SERVER[$name])) {
			$headerValue = $_SERVER[$name];
		}

		// Return the value
		return $headerValue;
	}
}

// [EOF]
?>