Recaptcha OOP Class

<?php
 
/*
	Be sure to set the public and private keys
*/
 
 
class recaptcha {
	private		$serverURLS		=	NULL;
	private		$ReCaptchaResponse	=	NULL;
	private		$keys			=	NULL;
 
 
	function __construct() {
		$this->serverURLS = new stdClass();
		$this->serverURLS->RECAPTCHA_API_SERVER = "http://api.recaptcha.net";
		$this->serverURLS->RECAPTCHA_API_SECURE_SERVER = "https://api-secure.recaptcha.net";
		$this->serverURLS->RECAPTCHA_VERIFY_SERVER = "api-verify.recaptcha.net";
 
		$this->ReCaptchaResponse = new stdClass();
		$this->ReCaptchaResponse->is_valid = NULL;
		$this->ReCaptchaResponse->error = NULL;
 
		$this->keys = new stdClass();
 
 
		$this->keys->recaptcha->publick = "6LcJOQkAAAAAABi3XIlSazOJTxbUNiVfQ0dkXAOT ";
		$this->keys->recaptcha->privatek = "INSERT YOUR PRIVATE KEY HERE";
 
		$this->keys->mailhide->publick = "INSERT YOUR PUBLIC KEY HERE";
		$this->keys->mailhide->privatek =INSERT YOUR OTHER PRIVATE KEY HERE";
 
 
	}
 
	private function _recaptcha_qsencode ($data) {
		$req = "";
		foreach ($data as $key => $value) {
			$req .= $key . '=' . urlencode( stripslashes($value) ) . '&';
		}
 
		// Cut the last '&'
		$req = substr($req, 0, strlen($req) - 1);
		return $req;
	}
 
	private function _recaptcha_http_post($host, $path, $data, $port = 80) {
 
		$req = $this->_recaptcha_qsencode ($data);
 
		$http_request  = "POST " . $path . " HTTP/1.0
";
		$http_request .= "Host: " . $host . "
";
		$http_request .= "Content-Type: application/x-www-form-urlencoded;
";
		$http_request .= "Content-Length: " . strlen($req) . "
";
		$http_request .= "User-Agent: reCAPTCHA/PHP
";
		$http_request .= "
";
		$http_request .= $req;
 
		$response = '';
		if(false == ($fs = @fsockopen($host, $port, $errno, $errstr, 10))) {
			die ('Could not open socket');
		}
 
		fwrite($fs, $http_request);
 
		while (!feof($fs)) {
			$response .= fgets($fs, 1160); // One TCP-IP packet
		}
		fclose($fs);
		$response = explode("
 
", $response, 2);
 
		return $response;
	}
 
	public function recaptcha_get_html ($error = null, $use_ssl = false) {
		if ($this->keys->recaptcha->publick == null || $this->keys->recaptcha->publick == "") {
			die ("To use reCAPTCHA you must get an API key from <a href='http://recaptcha.net/api/getkey'>http://recaptcha.net/api/getkey</a>");
		} else {}
 
		if ($use_ssl) {
			$server = $this->serverURLS->RECAPTCHA_API_SECURE_SERVER;
		}
		else {
			$server = $this->serverURLS->RECAPTCHA_API_SERVER;
		}
 
		$errorpart = "";
		if ($error) {
		   $errorpart = "&amp;error=" . $error;
		} else {}
		return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $this->keys->recaptcha->publick . $errorpart . '"></script>
 
		<noscript>
			<iframe src="'. $server . '/noscript?k=' . $this->keys->recaptcha->publick . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
			<textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
			<input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
		</noscript>';
	}
 
	public function recaptcha_check_answer ($remoteip, $challenge, $response, $extra_params = array()) {
		if ($this->keys->recaptcha->privatek == null || $this->keys->recaptcha->privatek == "") {
			die ("To use reCAPTCHA you must get an API key from <a href='http://recaptcha.net/api/getkey'>http://recaptcha.net/api/getkey</a>");
		} else {}
 
		if ($remoteip == null || $remoteip == "") {
			die ("For security reasons, you must pass the remote ip to reCAPTCHA");
		} else {}
 
 
 
		//discard spam submissions
		if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
			$this->ReCaptchaResponse->is_valid = false;
			$this->ReCaptchaResponse->error = "incorrect_captcha_sol";
			return $this->ReCaptchaResponse;
		}
 
		$response = $this->_recaptcha_http_post ($this->serverURLS->RECAPTCHA_VERIFY_SERVER, "/verify",
						  array (
							 "privatekey" => $this->keys->recaptcha->privatek,
							 "remoteip" => $remoteip,
							 "challenge" => $challenge,
							 "response" => $response
							 ) + $extra_params
						  );
 
		$answers = explode ("\n", $response[1]);
 
		if (trim ($answers [0]) == "true") {
			$this->ReCaptchaResponse->is_valid = true;
		}
		else {
			$this->ReCaptchaResponse->is_valid = false;
			$this->ReCaptchaResponse->error = str_replace("-", "_", $answers[1]);
		}
		return $this->ReCaptchaResponse;
 
	}
 
	private function recaptcha_get_signup_url ($domain = null, $appname = null) {
		return "http://recaptcha.net/api/getkey?" .  $this->_recaptcha_qsencode (array ("domain" => $domain, "app" => $appname));
	}
 
	private function _recaptcha_aes_pad($val) {
		$block_size = 16;
		$numpad = $block_size - (strlen ($val) % $block_size);
		return str_pad($val, strlen ($val) + $numpad, chr($numpad));
	}
 
	/* Mailhide related code */
 
	private function _recaptcha_aes_encrypt($val,$ky) {
		if (!function_exists ("mcrypt_encrypt")) {
			die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
		} else {}
		$mode = MCRYPT_MODE_CBC;
		$enc = MCRYPT_RIJNDAEL_128;
		$val = $this->_recaptcha_aes_pad($val);
		return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
	}
 
 
	private function _recaptcha_mailhide_urlbase64 ($x) {
		return strtr(base64_encode ($x), "+/", "-_");
	}
 
	/* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
	public function recaptcha_mailhide_url($email) {
		if ($this->keys->mailhide->publick == "" || $this->keys->mailhide->publick == null || $this->keys->mailhide->privatek == "" || $this->keys->mailhide->privatek == null) {
			die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
			     "you can do so at <a href='http://mailhide.recaptcha.net/apikey'>http://mailhide.recaptcha.net/apikey</a>");
		} else {}
 
		$ky = pack('H*', $this->keys->mailhide->privatek);
		$cryptmail = $this->_recaptcha_aes_encrypt ($email, $ky);
 
		return "http://mailhide.recaptcha.net/d?k=" . $this->keys->mailhide->publick . "&c=" . $this->_recaptcha_mailhide_urlbase64 ($cryptmail);
	}
 
	private function _recaptcha_mailhide_email_parts ($email) {
		$arr = preg_split("/@/", $email );
 
		if (strlen ($arr[0]) <= 4) {
			$arr[0] = substr ($arr[0], 0, 1);
		}
		else if (strlen ($arr[0]) <= 6) {
			$arr[0] = substr ($arr[0], 0, 3);
		}
		else {
			$arr[0] = substr ($arr[0], 0, 4);
		}
		return $arr;
	}
 
	public function recaptcha_mailhide_html($email) {
		$emailparts = $this->_recaptcha_mailhide_email_parts ($email);
		$url = $this->recaptcha_mailhide_url ($email);
 
		return htmlentities($emailparts[0]) . "<a href=\"" . htmlentities ($url) .
			"\" onclick=\"window.open('" . htmlentities ($url) . "', '', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300'); return false;\" title=\"Reveal this e-mail address\">...</a>@" . htmlentities ($emailparts [1]);
 
	}
}
 
 
 
/*
$recaptcha = new recaptcha();
$error = null;
 
if ($_POST["recaptcha_response_field"]) {
	$resp = $recaptcha->recaptcha_check_answer (
				$_SERVER["REMOTE_ADDR"],
				$_POST["recaptcha_challenge_field"],
				$_POST["recaptcha_response_field"]
			);
 
	if ($resp->is_valid) {
		echo "You got it!";
	} else {
		# set the error code so that we can display it
		$error = $resp->error;
	}
} else {}
 
echo $recaptcha->recaptcha_get_html($error);
 
 
 
 
 
The Mailhide version of example@example.com is
 echo $recaptcha->recaptcha_mailhide_html ("example@example.com");
 
The url for the email is:
 echo $recaptcha->recaptcha_mailhide_url ("example@example.com"); */
?>