title: Recaptcha response null for valid answer
body: <p>I am trying to integrate Recaptcha with one of my forms. I somehow managed to put the recaptcha on the form and having it submitted using Curl (with help from this post : <a href="https://stackoverflow.com/questions/10471942/what-is-blocking-fsockopen">What is blocking fsockopen?</a>). 
  But the recaptcha doesn't seem to accept even the right answers. </p>
  
  <p>I am no that good at PHP, but when debugged the code (offcourse using echo) found out that the the response is coming as empty. I have spent some 2 days on this, but still with no avail.</p>
  
  <p>Do i need to make any changes in recaptcha_check_answer after including Curl?</p>
  
  <p>Note: I am using WAMPServer 2.2 (Apache : 2.2.21, PHP : 5.3.10)</p>
  
  <p>Here are the excerpts from my form code and submit code.</p>
  
  <pre><code>/**  Recaptcha display Code**/
  require_once('recaptchalib.php');
  $publickey = "6LeamtESAAAAAH-77WMLP5NqvCQR8g3ZMJ7kZJvV"; // you got this from recaptcha.org
  
  $out = '&lt;div&gt;&lt;label for="captcha'.$form_id.'"&gt;* '.$field_object-&gt;field_label.'&lt;/label&gt;&lt;/div&gt;';
  $out .= recaptcha_get_html($publickey);
  return $out;
  
  
  /** Form Submit Code **/
  require_once('recaptchalib.php');
  $privatekey = "6LeamtESAAAAAFM1d1Zd2XRDlTjxZRH8OaTowg7n";
  
  $resp = recaptcha_check_answer($privatekey,
          $_SERVER["REMOTE_ADDR"],
          $_POST["recaptcha_challenge_field"],
              $_POST["recaptcha_response_field"]);
  
  if (!$resp-&gt;is_valid) {
      if (empty($resp-&gt;error))
          $this-&gt;setFormError('captcha', __('You copied the number from the captcha field incorrectly.', 'custom-contact-forms'));
      else $this-&gt;setFormError('captcha', $resp-&gt;error);
  }
  </code></pre>
  
  <p>Here is the modified recaptcha code</p>
  
  <pre><code>&lt;?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 =&gt; $value )
                  $req .= $key . '=' . urlencode( stripslashes($value) ) . '&amp;';
  
          // Cut the last '&amp;'
          $req=substr($req,0,strlen($req)-1);
          return $req;
  }
  
  function _recaptcha_http_post($host, $path, $data, $port = 80) {
  
          $req = _recaptcha_qsencode ($data);
          $request = curl_init("http://".$host.$path);
  
          curl_setopt($request, CURLOPT_USERAGENT, "reCAPTCHA/PHP");
          curl_setopt($request, CURLOPT_POST, true);
          curl_setopt($request, CURLOPT_POSTFIELDS, $req);
          curl_setopt($request, CURLOPT_RETURNTRANSFER, true);
  
          $response = curl_exec($request);
          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 &lt;a href='https://www.google.com/recaptcha/admin/create'&gt;https://www.google.com/recaptcha/admin/create&lt;/a&gt;");
      }
  
      if ($use_ssl) {
                  $server = RECAPTCHA_API_SECURE_SERVER;
          } else {
                  $server = RECAPTCHA_API_SERVER;
          }
  
          $errorpart = "";
          if ($error) {
             $errorpart = "&amp;amp;error=" . $error;
          }
          return '&lt;script type="text/javascript" src="'. $server . '/challenge?k=' . $pubkey . $errorpart . '"&gt;&lt;/script&gt;
  
      &lt;noscript&gt;
          &lt;iframe src="'. $server . '/noscript?k=' . $pubkey . $errorpart . '" height="300" width="500" frameborder="0"&gt;&lt;/iframe&gt;&lt;br/&gt;
          &lt;textarea name="recaptcha_challenge_field" rows="3" cols="40"&gt;&lt;/textarea&gt;
          &lt;input type="hidden" name="recaptcha_response_field" value="manual_challenge"/&gt;
      &lt;/noscript&gt;';
  }
  
  class ReCaptchaResponse {
          var $is_valid;
          var $error;
  }
  
  function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array())
  {
      if ($privkey == null || $privkey == '') {
          die ("To use reCAPTCHA you must get an API key from &lt;a href='https://www.google.com/recaptcha/admin/create'&gt;https://www.google.com/recaptcha/admin/create&lt;/a&gt;");
      }
      if ($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-&gt;is_valid = false;
                  $recaptcha_response-&gt;error = 'incorrect-captcha-sol';
                  return $recaptcha_response;
          }
  
          $response = _recaptcha_http_post (RECAPTCHA_VERIFY_SERVER, "/verify",
                                            array (
                                                   'privatekey' =&gt; $privkey,
                                                   'remoteip' =&gt; $remoteip,
                                                   'challenge' =&gt; $challenge,
                                                   'response' =&gt; $response
                                                   ) + $extra_params
                                            );
  
          $answers = explode ("\n", $response [1]);
          $recaptcha_response = new ReCaptchaResponse();
  
          if (trim ($answers [0]) == 'true') {
                  $recaptcha_response-&gt;is_valid = true;
          }
          else {
                  $recaptcha_response-&gt;is_valid = false;
                  $recaptcha_response-&gt;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' =&gt; $domain, 'app' =&gt; $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 &lt;a href='http://www.google.com/recaptcha/mailhide/apikey'&gt;http://www.google.com/recaptcha/mailhide/apikey&lt;/a&gt;");
      }
  
  
      $ky = pack('H*', $privkey);
      $cryptmail = _recaptcha_aes_encrypt ($email, $ky);
  
      return "http://www.google.com/recaptcha/mailhide/d?k=" . $pubkey . "&amp;c=" . _recaptcha_mailhide_urlbase64 ($cryptmail);
  }
  
  function _recaptcha_mailhide_email_parts ($email) {
      $arr = preg_split("/@/", $email );
  
      if (strlen ($arr[0]) &lt;= 4) {
          $arr[0] = substr ($arr[0], 0, 1);
      } else if (strlen ($arr[0]) &lt;= 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($emailparts[0]) . "&lt;a href='" . htmlentities ($url) .
          "' onclick=\"window.open('" . htmlentities ($url) . "', '', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=500,height=300'); return false;\" title=\"Reveal this e-mail address\"&gt;...&lt;/a&gt;@" . htmlentities ($emailparts [1]);
  
  }
  
  ?&gt;
  </code></pre>