/lib/recaptchalib.php
PHP | 343 lines | 167 code | 58 blank | 118 comment | 48 complexity | 5a71318ed15418b03388e8c8632f2b79 MD5 | raw file
- <?php
- /**
- * This is a PHP library that handles calling reCAPTCHA.
- * - Documentation and latest version
- * {@link http://code.google.com/apis/recaptcha/docs/php.html}
- * - Get a reCAPTCHA API Key
- * {@link https://www.google.com/recaptcha/admin/create}
- * - Discussion group
- * {@link http://groups.google.com/group/recaptcha}
- *
- * Copyright (c) 2007 reCAPTCHA -- {@link http://www.google.com/recaptcha}
- * 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.
- *
- * @package moodlecore
- * @copyright (c) 2007 reCAPTCHA -- {@link http://www.google.com/recaptcha}
- */
- /**
- * 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( $value ) . '&';
- // Cut the last '&'
- $req=substr($req,0,strlen($req)-1);
- return $req;
- }
- /**
- * Submits an HTTP POST to a reCAPTCHA server
- *
- * @global object
- * @param string $host
- * @param string $path
- * @param array $data
- * @param int port
- * @return array response
- */
- function _recaptcha_http_post($host, $path, $data, $port = 80, $https=false) {
- global $CFG;
- $protocol = 'http';
- if ($https) {
- $protocol = 'https';
- }
- require_once $CFG->libdir . '/filelib.php';
- $req = _recaptcha_qsencode ($data);
- $headers = array();
- $headers['Host'] = $host;
- $headers['Content-Type'] = 'application/x-www-form-urlencoded';
- $headers['Content-Length'] = strlen($req);
- $headers['User-Agent'] = 'reCAPTCHA/PHP';
- $results = download_file_content("$protocol://" . $host . $path, $headers, $data, false, 300, 20, true);
- if ($results) {
- return array(1 => $results);
- } else {
- return false;
- }
- }
- /**
- * Return the recaptcha challenge and image and javascript urls
- *
- * @param string $server server url
- * @param string $pubkey public key
- * @param string $errorpart error part to append
- * @return array the challenge hash, image and javascript url
- * @since Moodle 3.2
- */
- function recaptcha_get_challenge_hash_and_urls($server, $pubkey, $errorpart = '') {
- global $CFG;
- require_once($CFG->libdir . '/filelib.php');
- $html = download_file_content($server . '/noscript?k=' . $pubkey . $errorpart, null, null, false, 300, 20, true);
- preg_match('/image\?c\=([A-Za-z0-9\-\_]*)\"/', $html, $matches);
- $challengehash = $matches[1];
- $imageurl = $server . '/image?c=' . $challengehash;
- $jsurl = $server . '/challenge?k=' . $pubkey . $errorpart;
- return array($challengehash, $imageurl, $jsurl);
- }
- /**
- * 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.
- *
- * @global object
- * @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) {
- global $PAGE;
- $recaptchatype = optional_param('recaptcha', 'image', PARAM_TEXT);
- if ($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 = "&error=" . $error;
- }
- list($challengehash, $imageurl, $jsurl) = recaptcha_get_challenge_hash_and_urls($server, $pubkey, $errorpart);
- $strincorrectpleasetryagain = get_string('incorrectpleasetryagain', 'auth');
- $strenterthewordsabove = get_string('enterthewordsabove', 'auth');
- $strenterthenumbersyouhear = get_string('enterthenumbersyouhear', 'auth');
- $strgetanothercaptcha = get_string('getanothercaptcha', 'auth');
- $strgetanaudiocaptcha = get_string('getanaudiocaptcha', 'auth');
- $strgetanimagecaptcha = get_string('getanimagecaptcha', 'auth');
- $return = html_writer::script('', $jsurl);
- $return .= '<noscript>
- <div id="recaptcha_widget_noscript">
- <div id="recaptcha_image_noscript"><img src="' . $imageurl . '" alt="reCAPTCHA"/></div>';
- if ($error == 'incorrect-captcha-sol') {
- $return .= '<div class="recaptcha_only_if_incorrect_sol" style="color:red">' . $strincorrectpleasetryagain . '</div>';
- }
- if ($recaptchatype == 'image') {
- $return .= '<span class="recaptcha_only_if_image">' . $strenterthewordsabove . '</span>';
- } elseif ($recaptchatype == 'audio') {
- $return .= '<span class="recaptcha_only_if_audio">' . $strenterthenumbersyouhear . '</span>';
- }
- $return .= '<input type="text" id="recaptcha_response_field_noscript" name="recaptcha_response_field" />';
- $return .= '<input type="hidden" id="recaptcha_challenge_field_noscript" name="recaptcha_challenge_field" value="' . $challengehash . '" />';
- $return .= '<div><a href="signup.php">' . $strgetanothercaptcha . '</a></div>';
- // Disabling audio recaptchas for now: not language-independent
- /*
- if ($recaptchatype == 'image') {
- $return .= '<div class="recaptcha_only_if_image"><a href="signup.php?recaptcha=audio">' . $strgetanaudiocaptcha . '</a></div>';
- } elseif ($recaptchatype == 'audio') {
- $return .= '<div class="recaptcha_only_if_audio"><a href="signup.php?recaptcha=image">' . $strgetanimagecaptcha . '</a></div>';
- }
- */
- $return .= '
- </div>
- </noscript>';
- return $return;
- }
- /**
- * A ReCaptchaResponse is returned from recaptcha_check_answer()
- *
- * @package moodlecore
- * @copyright (c) 2007 reCAPTCHA -- {@link http://www.google.com/recaptcha}
- */
- class ReCaptchaResponse {
- var $is_valid;
- var $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 $response
- * @return ReCaptchaResponse
- */
- function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $https=false)
- {
- if ($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
- ),
- $https
- );
- $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 "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);
- }
- /**
- * 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 $arr;
- }
- /**
- * Gets html to display an email address given a public an private key.
- * to get a key, go to:
- *
- * http://www.google.com/recaptcha/mailhide/apikey
- */
- function recaptcha_mailhide_html($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]);
- }