<?php
/**
* This is a PHP library that handles calling reCAPTCHA.
* - Documentation and latest version
* https://developers.google.com/recaptcha/docs/php
* - Get a reCAPTCHA API Key
* https://www.google.com/recaptcha/admin/create
* - Discussion group
* http://groups.google.com/group/recaptcha
*
* @copyright Copyright (c) 2014, Google Inc.
* @link http://www.google.com/recaptcha
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/**
* A ReCaptchaResponse is returned from checkAnswer().
*/
class ReCaptchaResponse
{
	public $success;
	public $errorCodes;
}
class ReCaptcha
{
	private static $_signupUrl = "https://www.google.com/recaptcha/admin";
	private static $_siteVerifyUrl =
	"https://www.google.com/recaptcha/api/siteverify?";
	private $_secret;
	private static $_version = "php_1.0";
	/**
	* Constructor.
	*
	* @param string $secret shared secret between site and ReCAPTCHA server.
	*/
	function ReCaptcha($secret)
	{
		if ($secret == null || $secret == "") {
			die("To use reCAPTCHA you must get an API key from <a href='"
			. self::$_signupUrl . "'>" . self::$_signupUrl . "</a>");
		}
		$this->_secret=$secret;
	}
	/**
	* Encodes the given data into a query string format.
	*
	* @param array $data array of string elements to be encoded.
	*
	* @return string - encoded request.
	*/
	private function _encodeQS($data)
	{
		$req = "";
		foreach ($data as $key => $value) {
			$req .= $key . '=' . urlencode(stripslashes($value)) . '&';
		}
		// Cut the last '&'
		$req=substr($req, 0, strlen($req)-1);
		return $req;
	}
	/**
	* Submits an HTTP GET to a reCAPTCHA server.
	*
	* @param string $path url path to recaptcha server.
	* @param array $data array of parameters to be sent.
	*
	* @return array response
	*/
	private function _submitHTTPGet($path, $data)
	{
		$req = $this->_encodeQS($data);
		$response = file_get_contents($path . $req);
		return $response;
	}
	/**
	* Calls the reCAPTCHA siteverify API to verify whether the user passes
	* CAPTCHA test.
	*
	* @param string $remoteIp IP address of end user.
	* @param string $response response string from recaptcha verification.
	*
	* @return ReCaptchaResponse
	*/
	public function verifyResponse($remoteIp, $response)
	{
		// Discard empty solution submissions
		if ($response == null || strlen($response) == 0) {
			$recaptchaResponse = new ReCaptchaResponse();
			$recaptchaResponse->success = false;
			$recaptchaResponse->errorCodes = 'missing-input';
			return $recaptchaResponse;
		}
		$getResponse = $this->_submitHttpGet(
			self::$_siteVerifyUrl,
			array (
				'secret' => $this->_secret,
				'remoteip' => $remoteIp,
				'v' => self::$_version,
				'response' => $response
			)
		);
		$answers = json_decode($getResponse, true);
		$recaptchaResponse = new ReCaptchaResponse();
		if (trim($answers ['success']) == true) {
			$recaptchaResponse->success = true;
		} else {
			$recaptchaResponse->success = false;
			$recaptchaResponse->errorCodes = $answers [error-codes];
		}
		return $recaptchaResponse;
	}
}
?>