recaptchalib.php

<?php
/*
 * This is a PHP library that handles calling reCAPTCHA.
 *    - Documentation and latest version
 *          http://recaptcha.net/plugins/php/
 *    - Get a reCAPTCHA API Key
 *          https://www.google.com/recaptcha/admin/create
 *    - Discussion group
 *          http://groups.google.com/group/recaptcha
 *
 * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
 * AUTHORS:
 *   Mike Crawford
 *   Ben Maurer
 *
 * 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.
 */

/**
 * The reCAPTCHA server URL's
 */
define("RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api");
define("RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api");
define("RECAPTCHA_VERIFY_SERVER", "www.google.com");

/**
 * Encodes the given data into a query string format
 * @param $data - array of string elements to be encoded
 * @return string - encoded request
 */
function _recaptcha_qsencode($data)
{
        $req = "";
    foreach ($data as $key => $value) {
            $req .= $key . '=' . urlencode(stripslashes($value)) . '&';
    }

        // Cut the last '&'
        $req=substr($req, 0, strlen($req)-1);
        return $req;
}



/**
 * Submits an HTTP POST to a reCAPTCHA server
 * @param string $host
 * @param string $path
 * @param array $data
 * @param int port
 * @return array response
 */
function _recaptcha_http_post($host, $path, $data, $port = 80)
{

        $req = _recaptcha_qsencode($data);

        $http_request  = "POST $path HTTP/1.0\r\n";
        $http_request .= "Host: $host\r\n";
        $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
        $http_request .= "Content-Length: " . strlen($req) . "\r\n";
        $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
        $http_request .= "\r\n";
        $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("\r\n\r\n", $response, 2);

        return $response;
}



/**
 * Gets the challenge HTML (javascript and non-javascript version).
 * This is called from the browser, and the resulting reCAPTCHA HTML widget
 * is embedded within the HTML form it was called from.
 * @param string $pubkey A public key for reCAPTCHA
 * @param string $error The error given by reCAPTCHA (optional, default is null)
 * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)

 * @return string - The HTML to be embedded in the user's form.
 */
function recaptcha_get_html($pubkey, $error = null, $use_ssl = false)
{
    if ($pubkey == null || $pubkey == '') {
        die("To use reCAPTCHA you must get an API key from
            <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
    }
    
    if ($use_ssl) {
                $server = RECAPTCHA_API_SECURE_SERVER;
    } else {
            $server = RECAPTCHA_API_SERVER;
    }

        $errorpart = "";
    if ($error) {
        $errorpart = "&amp;error=" . $error;
    }
        return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>

    <noscript>
        <iframe src="'. $server . '/noscript?k=' . $pubkey . $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>';
}




/**
 * A ReCaptchaResponse is returned from recaptcha_check_answer()
 */
namespace Arastta\Component\Form\Resources;

class ReCaptchaResponse
{
    public $isValid;
    public $error;
}


/**
  * Calls an HTTP POST function to verify if the user's guess was correct
  * @param string $privkey
  * @param string $remoteip
  * @param string $challenge
  * @param string $response
  * @param array $extra_params an array of extra variables to post to the server
  * @return ReCaptchaResponse
  */
function recaptcha_check_answer($privkey, $remoteip, $challenge, $response, $extra_params = array())
{
    if ($privkey == null || $privkey == '') {
        die("To use reCAPTCHA you must get an API key from
            <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
    }

    if ($remoteip == null || $remoteip == '') {
        die("For security reasons, you must pass the remote ip to reCAPTCHA");
    }

    
    
        //discard spam submissions
    if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
            $recaptcha_response          = new ReCaptchaResponse();
            $recaptcha_response->isValid = false;
            $recaptcha_response->error   = 'incorrect-captcha-sol';
            return $recaptcha_response;
    }

        $response = _recaptcha_http_post(
            RECAPTCHA_VERIFY_SERVER,
            "/recaptcha/api/verify",
            array (
                                                 'privatekey' => $privkey,
                                                 'remoteip' => $remoteip,
                                                 'challenge' => $challenge,
                                                 'response' => $response
                                                 ) + $extra_params
        );

        $answers = explode("\n", $response [1]);
        $recaptcha_response = new ReCaptchaResponse();

        if (trim($answers [0]) == 'true') {
                $recaptcha_response->isValid = true;
        } else {
                $recaptcha_response->isValid = false;
                $recaptcha_response->error   = $answers [1];
        }
        return $recaptcha_response;

}

/**
 * gets a URL where the user can sign up for reCAPTCHA. If your application
 * has a configuration page where you enter a key, you should provide a link
 * using this function.
 * @param string $domain The domain where the page is hosted
 * @param string $appname The name of your application
 */
function recaptcha_get_signup_url($domain = null, $appname = null)
{
    return "https://www.google.com/recaptcha/admin/create?" .
                _recaptcha_qsencode(array ('domains' => $domain, 'app' => $appname));
}

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 */

function _recaptcha_aes_encrypt($val, $ky)
{
    if (! function_exists("openssl_encrypt")) {
        die("To use reCAPTCHA Mailhide, you need to have the OpenSSL php module installed.");
    }
    $val=_recaptcha_aes_pad($val);
    return openssl_encrypt($val, 'aes-128-cbc', $ky);
}


function _recaptcha_mailhide_urlbase64($x)
{
    return strtr(base64_encode($x), '+/', '-_');
}

/* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
function recaptcha_mailhide_url($pubkey, $privkey, $email)
{
    if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == 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://www.google.com/recaptcha/mailhide/apikey'>
                http://www.google.com/recaptcha/mailhide/apikey
             </a>"
        );
    }
    

    $ky = pack('H*', $privkey);
    $cryptmail = _recaptcha_aes_encrypt($email, $ky);
    
    return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey .
                "&c=" . _recaptcha_mailhide_urlbase64($cryptmail);
}

/**
 * gets the parts of the email to expose to the user.
 * eg, given johndoe@example,com return ["john", "example.com"].
 * the email is then displayed as john...@example.com
 */
function _recaptcha_mailhide_email_parts($email)
{
    $arr = preg_split("/@/", $email);

    if (strlen($arr[0]) <= 4) {
        $arr[0] = substr($arr[0], 0, 1);
    } elseif (strlen($arr[0]) <= 6) {
        $arr[0] = substr($arr[0], 0, 3);
    } else {
        $arr[0] = substr($arr[0], 0, 4);
    }
    return $arr;
}

/**
 * Gets html to display an email address given a public an private key.
 * to get a key, go to:
 *
 * http://www.google.com/recaptcha/mailhide/apikey
 */
function recaptcha_mailhide_html($pubkey, $privkey, $email)
{
    $emailparts = _recaptcha_mailhide_email_parts($email);
    $url = recaptcha_mailhide_url($pubkey, $privkey, $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]);

}