recaptchalib.php

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<?php
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 {
        public $is_valid;
        public $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 ) );
}
 
/* 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://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 );
    } elseif ( 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] );
 
}