 
function _recaptcha_http_post($host, $path, $data, $port = 80) { 
$req = _recaptcha_qsencode ($data); 
$response = ''; 
$url = $host.$path; 
$post_data = $req; 
$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL, $url); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
// 我們在POST數(shù)據(jù)哦！ 
curl_setopt($ch, CURLOPT_POST, 1); 
// 把post的變量加上 
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_data); 
$output = curl_exec($ch); 
curl_close($ch); 
//echo $output; 
$response = $output; 
return $response; 
} 
function recaptcha_check_answer ($privkey, $remoteip, $challenge, $response, $extra_params = array()) 
{ 
if ($privkey == null || $privkey == '') { 
die ("To use reCAPTCHA you must get an API key from <a ); 
} 
if ($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(); 
$pos = strpos($response, 'true'); 
if ($pos === false) { 
$recaptcha_response->is_valid = false; 
$recaptcha_response->error = $response; 
} else { 
$recaptcha_response->is_valid = true; 
} 
return $recaptcha_response; 
} 

2.demo.php

復制代碼代碼如下:

 
<html> 
<body> 
<form action="" method="post"> 
<?php 
require_once('recaptchalib.php'); 
// Get a key from https://www.google.com/recaptcha/admin/create 
$publickey = "你的公共key ---自己去http://www.google.com/recaptcha申請"; 
$privatekey = "你的私有key ---自己去http://www.google.com/recaptcha申請"; 
# the response from reCAPTCHA 
$resp = null; 
# the error code from reCAPTCHA, if any 
$error = null; 
# was there a reCAPTCHA response? 
if ($_POST["recaptcha_response_field"]) { 
$resp = recaptcha_check_answer ($privatekey, 
$_SERVER["REMOTE_ADDR"], 
$_POST["recaptcha_challenge_field"], 
$_POST["recaptcha_response_field"]); 
if ($resp->is_valid) { 
echo "You got it!"; 
} else { 
# set the error code so that we can display it 
$error = $resp->error; 
echo $error; 
//echo $_POST["recaptcha_challenge_field"]; 
//echo $_POST["recaptcha_response_field"]; 
} 
} 
echo recaptcha_get_html($publickey, $error); 
?> 
<br/> 
<input type="submit" value="submit" /> 
</form> 
</body> 
</html> 