1<?php
2/*
3 * This is a PHP library that handles calling reCAPTCHA.
4 *    - Documentation and latest version
5 *          http://recaptcha.net/plugins/php/
6 *    - Get a reCAPTCHA API Key
7 *          http://recaptcha.net/api/getkey
8 *    - Discussion group
9 *          http://groups.google.com/group/recaptcha
10 *
11 * Copyright (c) 2007 reCAPTCHA -- http://recaptcha.net
12 * AUTHORS:
13 *   Mike Crawford
14 *   Ben Maurer
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this software and associated documentation files (the "Software"), to deal
18 * in the Software without restriction, including without limitation the rights
19 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
20 * copies of the Software, and to permit persons to whom the Software is
21 * furnished to do so, subject to the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
31 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
32 * THE SOFTWARE.
33 */
34
35/**
36 * The reCAPTCHA server URL's
37 */
38define("PROTO", "http://");
39define("PROTO_SECURE", "https://");
40define("RECAPTCHA_API_SERVER", "www.google.com/recaptcha/api");
41define("RECAPTCHA_API_SECURE_SERVER", "www.google.com/recaptcha/api");
42define("RECAPTCHA_VERIFY_SERVER", "api-verify.recaptcha.net");
43
44/**
45 * Encodes the given data into a query string format
46 * @param $data - array of string elements to be encoded
47 * @return string - encoded request
48 */
49function _recaptcha_qsencode ($data) {
50        $req = "";
51        foreach ( $data as $key => $value )
52                $req .= $key . '=' . urlencode( stripslashes($value) ) . '&';
53
54        // Cut the last '&'
55        $req=substr($req,0,strlen($req)-1);
56        return $req;
57}
58
59
60
61/**
62 * Submits an HTTP POST to a reCAPTCHA server
63 * @param string $host
64 * @param string $path
65 * @param array $data
66 * @param int port
67 * @return array response
68 */
69function _recaptcha_http_post($host, $path, $data, $port = 80) {
70
71        $req = _recaptcha_qsencode ($data);
72
73        $http_request  = "POST $path HTTP/1.0\r\n";
74        $http_request .= "Host: $host\r\n";
75        $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
76        $http_request .= "Content-Length: " . strlen($req) . "\r\n";
77        $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
78        $http_request .= "\r\n";
79        $http_request .= $req;
80
81        $response = '';
82        if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
83                die ('Could not open socket');
84        }
85
86        fwrite($fs, $http_request);
87
88        while ( !feof($fs) )
89                $response .= fgets($fs, 1160); // One TCP-IP packet
90        fclose($fs);
91        $response = explode("\r\n\r\n", $response, 2);
92
93        return $response;
94}
95
96
97
98/**
99 * Gets the challenge HTML (javascript and non-javascript version).
100 * This is called from the browser, and the resulting reCAPTCHA HTML widget
101 * is embedded within the HTML form it was called from.
102 * @param string $pubkey A public key for reCAPTCHA
103 * @param string $error The error given by reCAPTCHA (optional, default is null)
104 * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
105
106 * @return string - The HTML to be embedded in the user's form.
107 */
108function recaptcha_get_html ($pubkey, $error = null, $use_ssl = false)
109{
110	if ($pubkey == null || $pubkey == '') {
111		die ("To use reCAPTCHA you must get an API key from <a href='http://www.google.com/recaptcha'>http://www.google.com/recaptcha</a>");
112	}
113
114	if ($use_ssl) {
115                $server = PROTO_SECURE . RECAPTCHA_API_SECURE_SERVER;
116        } else {
117                $server = PROTO . RECAPTCHA_API_SERVER;
118        }
119
120        $errorpart = "";
121        if ($error) {
122           $errorpart = "&amp;error=" . $error;
123        }
124        return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
125
126	<noscript>
127  		<iframe src="'. $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
128  		<textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
129  		<input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
130	</noscript>';
131}
132
133
134/**
135 * A ReCaptchaResponse is returned from recaptcha_check_answer()
136 */
137class ReCaptchaResponse {
138        var $is_valid;
139        var $error;
140}
141
142
143/**
144  * Calls an HTTP POST function to verify if the user's guess was correct
145  * @param string $privkey
146  * @param string $remoteip
147  * @param string $challenge
148  * @param string $response
149  * @param array $extra_params an array of extra variables to post to the server
150  * @return ReCaptchaResponse
151  */
152function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
153{
154	if ($privkey == null || $privkey == '') {
155		die ("To use reCAPTCHA you must get an API key from <a href='http://www.google.com/recaptcha'>http://www.google.com/recaptcha</a>");
156	}
157
158	if ($remoteip == null || $remoteip == '') {
159		die ("For security reasons, you must pass the remote ip to reCAPTCHA");
160	}
161
162
163
164        //discard spam submissions
165        if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
166                $recaptcha_response = new ReCaptchaResponse();
167                $recaptcha_response->is_valid = false;
168                $recaptcha_response->error = 'incorrect-captcha-sol';
169                return $recaptcha_response;
170        }
171
172        $response = _recaptcha_http_post (RECAPTCHA_VERIFY_SERVER, "/verify",
173                                          array (
174                                                 'privatekey' => $privkey,
175                                                 'remoteip' => $remoteip,
176                                                 'challenge' => $challenge,
177                                                 'response' => $response
178                                                 ) + $extra_params
179                                          );
180
181        $answers = explode ("\n", $response [1]);
182        $recaptcha_response = new ReCaptchaResponse();
183
184        if (trim ($answers [0]) == 'true') {
185                $recaptcha_response->is_valid = true;
186        }
187        else {
188                $recaptcha_response->is_valid = false;
189                $recaptcha_response->error = $answers [1];
190        }
191        return $recaptcha_response;
192
193}
194
195/**
196 * gets a URL where the user can sign up for reCAPTCHA. If your application
197 * has a configuration page where you enter a key, you should provide a link
198 * using this function.
199 * @param string $domain The domain where the page is hosted
200 * @param string $appname The name of your application
201 */
202function recaptcha_get_signup_url ($domain = null, $appname = null) {
203	return "http://recaptcha.net/api/getkey?" .  _recaptcha_qsencode (array ('domain' => $domain, 'app' => $appname));
204}
205
206function _recaptcha_aes_pad($val) {
207	$block_size = 16;
208	$numpad = $block_size - (strlen ($val) % $block_size);
209	return str_pad($val, strlen ($val) + $numpad, chr($numpad));
210}
211
212/* Mailhide related code */
213
214function _recaptcha_aes_encrypt($val,$ky) {
215	if (! function_exists ("mcrypt_encrypt")) {
216		die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
217	}
218	$mode=MCRYPT_MODE_CBC;
219	$enc=MCRYPT_RIJNDAEL_128;
220	$val=_recaptcha_aes_pad($val);
221	return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
222}
223
224
225function _recaptcha_mailhide_urlbase64 ($x) {
226	return strtr(base64_encode ($x), '+/', '-_');
227}
228
229/* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
230function recaptcha_mailhide_url($pubkey, $privkey, $email) {
231	if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null) {
232		die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
233		     "you can do so at <a href='http://mailhide.recaptcha.net/apikey'>http://mailhide.recaptcha.net/apikey</a>");
234	}
235
236
237	$ky = pack('H*', $privkey);
238	$cryptmail = _recaptcha_aes_encrypt ($email, $ky);
239
240	return "http://mailhide.recaptcha.net/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64 ($cryptmail);
241}
242
243/**
244 * gets the parts of the email to expose to the user.
245 * eg, given johndoe@example,com return ["john", "example.com"].
246 * the email is then displayed as john...@example.com
247 */
248function _recaptcha_mailhide_email_parts ($email) {
249	$arr = preg_split("/@/", $email );
250
251	if (strlen ($arr[0]) <= 4) {
252		$arr[0] = substr ($arr[0], 0, 1);
253	} else if (strlen ($arr[0]) <= 6) {
254		$arr[0] = substr ($arr[0], 0, 3);
255	} else {
256		$arr[0] = substr ($arr[0], 0, 4);
257	}
258	return $arr;
259}
260
261/**
262 * Gets html to display an email address given a public an private key.
263 * to get a key, go to:
264 *
265 * http://mailhide.recaptcha.net/apikey
266 */
267function recaptcha_mailhide_html($pubkey, $privkey, $email) {
268	$emailparts = _recaptcha_mailhide_email_parts ($email);
269	$url = recaptcha_mailhide_url ($pubkey, $privkey, $email);
270
271	return htmlentities($emailparts[0]) . "<a href='" . htmlentities ($url) .
272		"' onclick=\"window.open('" . htmlentities ($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]);
273
274}
275
276
277?>
278