recaptchalib.php

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<?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.
 */

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");

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;
}


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;
}


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>';
}


class ReCaptchaResponse
{
    var $is_valid;
    var $error;
}

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->is_valid = 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->is_valid = true;
    } else {
        $recaptcha_response->is_valid = false;
        $recaptcha_response->error = $answers [1];
    }
    return $recaptcha_response;

}

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));
}

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.");
    }
    $mode = MCRYPT_MODE_CBC;
    $enc = MCRYPT_RIJNDAEL_128;
    $val = _recaptcha_aes_pad($val);
    return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
}

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

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);
}

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;
}

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]);
}