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   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   *          https://www.google.com/recaptcha/admin/create
   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   */
  38  define("RECAPTCHA_API_SERVER", "http://www.google.com/recaptcha/api");
  39  define("RECAPTCHA_API_SECURE_SERVER", "https://www.google.com/recaptcha/api");
  40  define("RECAPTCHA_VERIFY_SERVER", "www.google.com");
  41  
  42  /**
  43   * Encodes the given data into a query string format
  44   * @param $data - array of string elements to be encoded
  45   * @return string - encoded request
  46   */
  47  function _recaptcha_qsencode ($data) {
  48      $req = "";
  49      foreach ( $data as $key => $value )
  50              $req .= $key . '=' . urlencode( stripslashes($value) ) . '&';
  51  
  52      // Cut the last '&'
  53      $req=substr($req,0,strlen($req)-1);
  54      return $req;
  55  }
  56  
  57  
  58  
  59  /**
  60   * Submits an HTTP POST to a reCAPTCHA server
  61   * @param string $host
  62   * @param string $path
  63   * @param array $data
  64   * @param int port
  65   * @return array response
  66   */
  67  function _recaptcha_http_post($host, $path, $data, $port = 80) {
  68  
  69      $req = _recaptcha_qsencode ($data);
  70  
  71      $http_request  = "POST $path HTTP/1.0\r\n";
  72      $http_request .= "Host: $host\r\n";
  73      $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
  74      $http_request .= "Content-Length: " . strlen($req) . "\r\n";
  75      $http_request .= "User-Agent: reCAPTCHA/PHP\r\n";
  76      $http_request .= "\r\n";
  77      $http_request .= $req;
  78  
  79      $response = '';
  80      if( false == ( $fs = @fsockopen($host, $port, $errno, $errstr, 10) ) ) {
  81              die ('Could not open socket');
  82      }
  83  
  84      fwrite($fs, $http_request);
  85  
  86      while ( !feof($fs) )
  87              $response .= fgets($fs, 1160); // One TCP-IP packet
  88      fclose($fs);
  89      $response = explode("\r\n\r\n", $response, 2);
  90  
  91      return $response;
  92  }
  93  
  94  
  95  
  96  /**
  97   * Gets the challenge HTML (javascript and non-javascript version).
  98   * This is called from the browser, and the resulting reCAPTCHA HTML widget
  99   * is embedded within the HTML form it was called from.
 100   * @param string $pubkey A public key for reCAPTCHA
 101   * @param string $error The error given by reCAPTCHA (optional, default is null)
 102   * @param boolean $use_ssl Should the request be made over ssl? (optional, default is false)
 103  
 104   * @return string - The HTML to be embedded in the user's form.
 105   */
 106  function recaptcha_get_html ($pubkey, $error = null, $use_ssl = false)
 107  {
 108      if ($pubkey == null || $pubkey == '') {
 109          die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
 110      }
 111      
 112      if ($use_ssl) {
 113                  $server = RECAPTCHA_API_SECURE_SERVER;
 114      } else {
 115              $server = RECAPTCHA_API_SERVER;
 116      }
 117  
 118      $errorpart = "";
 119      if ($error) {
 120         $errorpart = "&amp;error=" . $error;
 121      }
 122      return '<script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"></script>
 123  
 124      <noscript>
 125            <iframe src="'. $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"></iframe><br/>
 126            <textarea name="recaptcha_challenge_field" rows="3" cols="40"></textarea>
 127            <input type="hidden" name="recaptcha_response_field" value="manual_challenge"/>
 128      </noscript>';
 129  }
 130  
 131  
 132  
 133  
 134  /**
 135   * A ReCaptchaResponse is returned from recaptcha_check_answer()
 136   */
 137  class 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 $extra_params an array of extra variables to post to the server
 150    * @return ReCaptchaResponse
 151    */
 152  function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
 153  {
 154      if ($privkey == null || $privkey == '') {
 155          die ("To use reCAPTCHA you must get an API key from <a href='https://www.google.com/recaptcha/admin/create'>https://www.google.com/recaptcha/admin/create</a>");
 156      }
 157  
 158      if ($remoteip == null || $remoteip == '') {
 159          die ("For security reasons, you must pass the remote ip to reCAPTCHA");
 160      }
 161  
 162      //discard spam submissions
 163      if ($challenge == null || strlen($challenge) == 0 || $response == null || strlen($response) == 0) {
 164              $recaptcha_response = new ReCaptchaResponse();
 165              $recaptcha_response->is_valid = false;
 166              $recaptcha_response->error = '@@reCAPTCHA failed@@';
 167              return $recaptcha_response;
 168      }
 169  
 170      $response = _recaptcha_http_post (RECAPTCHA_VERIFY_SERVER, "/recaptcha/api/verify",
 171                                        array (
 172                                               'privatekey' => $privkey,
 173                                               'remoteip' => $remoteip,
 174                                               'challenge' => $challenge,
 175                                               'response' => $response
 176                                               ) + $extra_params
 177                                        );
 178  
 179      $answers = explode ("\n", $response[1]);
 180      
 181      $recaptcha_response = new ReCaptchaResponse();
 182  
 183      if (trim ($answers[0]) == 'true') {
 184              $recaptcha_response->is_valid = true;
 185      }
 186      else {
 187              $recaptcha_response->is_valid = false;
 188              $recaptcha_response->error = str_replace("\\n", '', trim(trim($answers[1]),"'"));
 189      }
 190      return $recaptcha_response;
 191  
 192  }
 193  
 194  /**
 195   * gets a URL where the user can sign up for reCAPTCHA. If your application
 196   * has a configuration page where you enter a key, you should provide a link
 197   * using this function.
 198   * @param string $domain The domain where the page is hosted
 199   * @param string $appname The name of your application
 200   */
 201  function recaptcha_get_signup_url ($domain = null, $appname = null) {
 202      return "https://www.google.com/recaptcha/admin/create?" .  _recaptcha_qsencode (array ('domains' => $domain, 'app' => $appname));
 203  }
 204  
 205  function _recaptcha_aes_pad($val) {
 206      $block_size = 16;
 207      $numpad = $block_size - (strlen ($val) % $block_size);
 208      return str_pad($val, strlen ($val) + $numpad, chr($numpad));
 209  }
 210  
 211  /* Mailhide related code */
 212  
 213  function _recaptcha_aes_encrypt($val,$ky) {
 214      if (! function_exists ("mcrypt_encrypt")) {
 215          die ("To use reCAPTCHA Mailhide, you need to have the mcrypt php module installed.");
 216      }
 217      $mode=MCRYPT_MODE_CBC;   
 218      $enc=MCRYPT_RIJNDAEL_128;
 219      $val=_recaptcha_aes_pad($val);
 220      return mcrypt_encrypt($enc, $ky, $val, $mode, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
 221  }
 222  
 223  
 224  function _recaptcha_mailhide_urlbase64 ($x) {
 225      return strtr(base64_encode ($x), '+/', '-_');
 226  }
 227  
 228  /* gets the reCAPTCHA Mailhide url for a given email, public key and private key */
 229  function recaptcha_mailhide_url($pubkey, $privkey, $email) {
 230      if ($pubkey == '' || $pubkey == null || $privkey == "" || $privkey == null) {
 231          die ("To use reCAPTCHA Mailhide, you have to sign up for a public and private key, " .
 232               "you can do so at <a href='http://www.google.com/recaptcha/mailhide/apikey'>http://www.google.com/recaptcha/mailhide/apikey</a>");
 233      }
 234      
 235  
 236      $ky = pack('H*', $privkey);
 237      $cryptmail = _recaptcha_aes_encrypt ($email, $ky);
 238      
 239      return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey . "&c=" . _recaptcha_mailhide_urlbase64 ($cryptmail);
 240  }
 241  
 242  /**
 243   * gets the parts of the email to expose to the user.
 244   * eg, given johndoe@example,com return ["john", "example.com"].
 245   * the email is then displayed as john...@example.com
 246   */
 247  function _recaptcha_mailhide_email_parts ($email) {
 248      $arr = preg_split("/@/", $email );
 249  
 250      if (strlen ($arr[0]) <= 4) {
 251          $arr[0] = substr ($arr[0], 0, 1);
 252      } else if (strlen ($arr[0]) <= 6) {
 253          $arr[0] = substr ($arr[0], 0, 3);
 254      } else {
 255          $arr[0] = substr ($arr[0], 0, 4);
 256      }
 257      return $arr;
 258  }
 259  
 260  /**
 261   * Gets html to display an email address given a public an private key.
 262   * to get a key, go to:
 263   *
 264   * http://www.google.com/recaptcha/mailhide/apikey
 265   */
 266  function recaptcha_mailhide_html($pubkey, $privkey, $email) {
 267      $emailparts = _recaptcha_mailhide_email_parts ($email);
 268      $url = recaptcha_mailhide_url ($pubkey, $privkey, $email);
 269      
 270      return htmlentities($emailparts[0]) . "<a href='" . htmlentities ($url) .
 271          "' onclick=\"window.open('" . htmlentities ($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]);
 272  
 273  }
 274  
 275  ?>