Google captcha snippet

example.php

<?php

	$captcha_res  = $_POST['g-recaptcha-response'];
	$secret_code = "SECRET KEY";

	if (!empty($_SERVER['HTTP_CLIENT_IP'])) {
	    $ip = $_SERVER['HTTP_CLIENT_IP'];
	} elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
	    $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
	} else {
	    $ip = $_SERVER['REMOTE_ADDR'];
	}

	$ch = curl_init();

	curl_setopt($ch, CURLOPT_URL,"https://www.google.com/recaptcha/api/siteverify");
	curl_setopt($ch, CURLOPT_POST, 1);
	curl_setopt($ch, CURLOPT_POSTFIELDS,
		"secret=" . $secret_code . "&response=". $captcha_res ."&remoteip=". $ip);

	curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

	$server_output = curl_exec ($ch);

	curl_close ($ch);

	$res = json_decode($server_output);

	if($res->success){
    // Do something
  }