使用纯 JavaScript 和 PHP 由 Google reCAPTCHA v3 验证的联系表单的简单示例
tldr;跳到底部的代码。
相关的 reCAPTCHA 文档等：
（如果 Google 正在倾听，我们喜欢您的工作，如果能将一些更详细的示例链接到上述页面，那就太好了。）
概述：
- 从 Google 获取密钥
- 在html头部加载recaptcha/api.js
- 使用 JavaScript 劫持表单提交，然后从 Google 获取令牌
- 向您的服务器提交带有令牌的表单
- 从您网站的后端向 Google 发出请求以验证
表单提交
- 解释响应并根据需要继续
重要提示：“success”响应参数仅表示验证码是否评估成功，并不表示提交是否可能是垃圾邮件。
'score' 参数是您需要了解的结果。分数越高（0 到 1 之间的数字），提交的内容就越有可能是真实的，这取决于您接受的阈值（例如 0.5）。
详细说明：
将以下行添加到 HTML 的头部以加载 recaptcha api.js 代码：
<script src="https://www.google.com/recaptcha/api.js?render=$reCAPTCHA_site_key"></script>
（其中$reCAPTCHA_site_key 是您的公共“站点密钥”，我已将其保存在“config.php”文件中。）
您需要向您的服务器提交一个令牌（从 Google 接收且对每个表单提交都是唯一的）。我认为通过 POST 将其与其他表单数据一起发送是最简单的。为此，我在表单中包含了一个隐藏字段，如下所示：
<form id="contactForm" method="post" action="contact">
<!-- other form inputs -->
<input type="hidden" id="gRecaptchaResponse" name="gRecaptchaResponse">
<input type="submit" name="contact_submit" value="Send message">
</form>
（注意，“联系人”是contact.php，但我已经用.htaccess“重写”了网址）
现在我们需要劫持默认的表单提交来生成令牌。我们可以在页面加载时生成令牌，但由于令牌仅在两分钟内有效（如果我正确阅读了 https://developers.google.com/recaptcha/docs/verify 页面）我认为最好在需要将其发送到您网站的服务器时获取它.
为此，我在结束表单标记之后添加了以下内容：
<script>
contactForm.addEventListener('submit', event => {
event.preventDefault()
validate(contactForm)
});
</script>
我将validate(form) 函数放在了结束正文标记之前：
function validate(form) {
//perform optional error checking on form. If no errors then request a token and put it into the hidden field
getRecaptchaToken(form)
}
//some other (optional) form validation functions
function getRecaptchaToken(form) {
grecaptcha.ready(function() {
grecaptcha.execute($reCAPTCHA_site_key, {action: 'contactForm'}).then(function(token) {
gRecaptchaResponse.value = token //set the value of the hidden field
form.submit() //submit the form
});
});
}
注意事项：
-
$reCAPTCHA_site_key 是您的公共站点密钥
-
action: 'contactForm' 标识此特定的提交
在 Google reCAPTCHA 仪表板中的表单，并在后端确认它是预期的，这是一个推荐的额外
安全步骤
在 PHP 主文件中，当收到表单提交时：
//get the IP address of the origin of the submission
$ip = $_SERVER['REMOTE_ADDR'];
//construct the url to send your private Secret Key, token and (optionally) IP address of the form submitter to Google to get a spam rating for the submission (I've saved '$reCAPTCHA_secret_key' in config.php)
$url = 'https://www.google.com/recaptcha/api/siteverify?secret=' . urlencode($reCAPTCHA_secret_key) . '&response=' . urlencode($g_recaptcha_response) . '&remoteip=' . urlencode($ip);
//save the response, e.g. print_r($response) prints { "success": true, "challenge_ts": "2019-07-24T11:19:07Z", "hostname": "your-website-domain.co.uk", "score": 0.9, "action": "contactForm" }
$response = file_get_contents($url);
//decode the response, e.g. print_r($responseKeys) prints Array ( [success] => 1 [challenge_ts] => 2019-07-24T11:19:07Z [hostname] => your-website-domain.co.uk [score] => 0.9 [action] => contactForm )
$responseKeys = json_decode($response, true);
//check if the test was done OK, if the action name is correct and if the score is above your chosen threshold (again, I've saved '$g_recaptcha_allowable_score' in config.php)
if ($responseKeys["success"] && $responseKeys["action"] == 'contactForm') {
if ($responseKeys["score"] >= $g_recaptcha_allowable_score) {
//send email with contact form submission data to site owner/ submit to database/ etc
//redirect to confirmation page or whatever you need to do
} elseif ($responseKeys["score"] < $g_recaptcha_allowable_score) {
//failed spam test. Offer the visitor the option to try again or use an alternative method of contact.
}
} elseif($responseKeys["error-codes"]) { //optional
//handle errors. See notes below for possible error codes
//personally I'm probably going to handle errors in much the same way by sending myself a the error code for debugging and offering the visitor the option to try again or use an alternative method of contact
} else {
//unkown screw up. Again, offer the visitor the option to try again or use an alternative method of contact.
}
注意事项：
- 这是将在 Google 响应中的数据
（作为 JSON 对象返回）：
{
"success": true|false, // whether this request was a valid reCAPTCHA token for your site
"score": number // the score for this request (0.0 - 1.0)
"action": string // the action name for this request (important to verify)
"challenge_ts": timestamp, // timestamp of the challenge load (ISO format yyyy-MM-dd'T'HH:mm:ssZZ)
"hostname": string, // the hostname of the site where the reCAPTCHA was solved
"error-codes": [...] // optional
}
- 这些是可能的错误代码：
- missing-input-secret：secret 参数丢失。
- invalid-input-secret：secret 参数无效或格式错误。
- missing-input-response：缺少响应参数。
- invalid-input-response：响应参数无效或格式错误。
- bad-request：请求无效或格式错误。
- 超时或重复：响应不再有效；要么太
旧的或以前使用过的。
把它们放在一起：
contact.php
<?php //contact.php
require_once('config.php');
//do server-side validation of other form fields
if (/*form has been submitted and has passed server-side validation of the other form fields*/) {
$ip = $_SERVER['REMOTE_ADDR'];
$url = 'https://www.google.com/recaptcha/api/siteverify?secret=' . urlencode($reCAPTCHA_secret_key) . '&response=' . urlencode($g_recaptcha_response) . '&remoteip=' . urlencode($ip);
$response = file_get_contents($url);
$responseKeys = json_decode($response, true);
if ($responseKeys["success"] && $responseKeys["action"] == 'contactForm') {
if ($responseKeys["score"] >= $g_recaptcha_allowable_score) {
//send email with contact form submission data to site owner/ submit to database/ etc
//redirect to confirmation page or whatever you need to do
} elseif ($responseKeys["score"] < $g_recaptcha_allowable_score) {
//failed spam test. Offer the visitor the option to try again or use an alternative method of contact.
}
} elseif($responseKeys["error-codes"]) { //optional
//handle errors. See notes below for possible error codes
//(I handle errors by sending myself an email with the error code for debugging and offering the visitor the option to try again or use an alternative method of contact)
} else {
//unkown screw up. Again, offer the visitor the option to try again or use an alternative method of contact.
}
exit;
} else { //(re)display the page with the form
echo <<<_END
<!DOCTYPE html>
<html lang="en">
<head>
<title>Contact | Your website</title>
<link rel="stylesheet" href="css/style.css">
<script src="https://www.google.com/recaptcha/api.js?render=$reCAPTCHA_site_key"></script>
</head>
<body>
<!-- header etc -->
<form id="contactForm" method="post" action="contact">
//other form inputs
<input type="hidden" id="gRecaptchaResponse" name="gRecaptchaResponse">
<input type="submit" name="contact_submit" value="Send message">
</form>
<script>
contactForm.addEventListener('submit', event => {
event.preventDefault()
validate(contactForm)
});
</script>
<!-- footer etc -->
<script>
function validate(form) {
//perform optional client-side error checking of the form. If no errors are found then request a token and put it into the hidden field. Finally submit the form.
getRecaptchaToken(form)
}
//some (optional) form field validation functions
function getRecaptchaToken(form) {
grecaptcha.ready(function() {
grecaptcha.execute($reCAPTCHA_site_key, {action: 'contactForm'}).then(function(token) {
gRecaptchaResponse.value = token
form.submit()
});
});
}
</script>
</body>
</html>
_END;
config.php
<?php //config.php
//other site settings
// Google reCAPTCHA v3 keys
// For reducing spam contact form submissions
// Site key (public)
$reCAPTCHA_site_key = 'N0t-a-real-0N3_JHbnbUJ-BLAHBLAH_Blahblah';
// Secret key
$reCAPTCHA_secret_key = 'N0t-a-real-0N3_i77tyYGH7Ty6UfG-blah';
// Min score returned from reCAPTCHA to allow form submission
$g_recaptcha_allowable_score = 0.5; //Number between 0 and 1. You choose this. Setting a number closer to 0 will let through more spam, closer to 1 and you may start to block valid submissions.