imagecms / ImageCMS

application/helpers/recaptcha_helper.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
 *          http://recaptcha.net/api/getkey
 *    - 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://api.recaptcha.net');
define('RECAPTCHA_API_SECURE_SERVER', 'https://api-secure.recaptcha.net');
define('RECAPTCHA_VERIFY_SERVER', 'api-verify.recaptcha.net');

/**
 * 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

Should the return type not be null|array? Also, consider making the array more specific, something like array<String>, or String[].

 */
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.

Should the return type not be null|string?

 */
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='http://recaptcha.net/api/getkey'>http://recaptcha.net/api/getkey</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()
 */
class ReCaptchaResponse
{

    public $is_valid;

    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

Should the return type not be ReCaptchaResponse|null?

 */
function recaptcha_check_answer($privkey, $remoteip, $challenge, $response, $extra_params = []) {

    if ($privkey == null || $privkey == '') {
        die("To use reCAPTCHA you must get an API key from <a href='http://recaptcha.net/api/getkey'>http://recaptcha.net/api/getkey</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,
        '/verify',
        [
         '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;
}

/**
 * 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 'http://recaptcha.net/api/getkey?' . _recaptcha_qsencode(['domain' => $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('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), '+/', '-_');
}

/* 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://mailhide.recaptcha.net/apikey'>http://mailhide.recaptcha.net/apikey</a>"
        );
    }

    $ky = pack('H*', $privkey);
    $cryptmail = _recaptcha_aes_encrypt($email, $ky);

    return 'http://mailhide.recaptcha.net/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);
    } else if (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://mailhide.recaptcha.net/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]);
}