How to verify Google reCAPTCHA v3 on the server side?
P粉904191507
2023-08-27 16:48:47
<p>I just set up the new Google Captcha with checkboxes and it works fine on the front end, but I don't know how to handle it on the server side using PHP. I tried using the old code below but the form is sent even though the verification code is invalid. </p>
<pre class="brush:php;toolbar:false;">require_once('recaptchalib.php');
$privatekey = "my key";
$resp = recaptcha_check_answer ($privatekey,
$_SERVER["REMOTE_ADDR"],
$_POST["recaptcha_challenge_field"],
$_POST["recaptcha_response_field"]);
if (!$resp->is_valid) {
$errCapt='<p style="color:#D6012C ">The CAPTCHA Code was not entered correctly.</p>';}</pre>
<p><br /></p>
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Private Key Security
While the answers here certainly work, they use
GETrequests, which exposes your private key (even withhttps). On Google Developers, the specified method isPOST.For more details: https://stackoverflow.com/a/323286/1680919
Verify via POST
function isValid() { try { $url = 'https://www.google.com/recaptcha/api/siteverify'; $data = ['secret' => '[YOUR SECRET KEY]', 'response' => $_POST['g-recaptcha-response'], 'remoteip' => $_SERVER['REMOTE_ADDR']]; $options = [ 'http' => [ 'header' => "Content-type: application/x-www-form-urlencoded\r\n", 'method' => 'POST', 'content' => http_build_query($data) ] ]; $context = stream_context_create($options); $result = file_get_contents($url, false, $context); return json_decode($result)->success; } catch (Exception $e) { return null; } }Array syntax: I use the "new" array syntax (
[and]instead ofarray(..)). If your version of php doesn't support this yet, you will have to edit these 3 array definitions accordingly (see comments).Return value: If the user is valid, this function returns
true; if it is invalid, it returnsfalse; if the user is valid, it returnsnullIf an error occurs. For example, you can use it simply by writingif (isValid()) { ... }This is the solution
index.html
<html> <head> <title>Google recapcha demo - Codeforgeek</title> <script src='https://www.google.com/recaptcha/api.js'></script> </head> <body> <h1>Google reCAPTHA Demo</h1> <form id="comment_form" action="form.php" method="post"> <input type="email" placeholder="Type your email" size="40"><br><br> <textarea name="comment" rows="8" cols="39"></textarea><br><br> <input type="submit" name="submit" value="Post comment"><br><br> <div class="g-recaptcha" data-sitekey="=== Your site key ==="></div> </form> </body> </html>verification.php
<?php $email; $comment; $captcha; if(isset($_POST['email'])) $email=$_POST['email']; if(isset($_POST['comment'])) $comment=$_POST['comment']; if(isset($_POST['g-recaptcha-response'])) $captcha=$_POST['g-recaptcha-response']; if(!$captcha){ echo '<h2>Please check the the captcha form.</h2>'; exit; } $response = json_decode(file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=YOUR SECRET KEY&response=".$captcha."&remoteip=".$_SERVER['REMOTE_ADDR']), true); if($response['success'] == false) { echo '<h2>You are spammer ! Get the @$%K out</h2>'; } else { echo '<h2>Thanks for posting comment.</h2>'; } ?>http://codeforgeek.com/2014/12/google-recaptcha-tutorial /