WordPress HappyForms reCAPTCHA – solution for free version of HappyForms plugin

wordpress-happyforms-recaptcha.php

<?php

/**
 * Google reCAPTCHA for WordPress HappyForms
 *
 * @author Tomas Kavalek <tomas.kavalek@gmail.com>
 * @version 1.0.0
 */
class HappyForms_Recaptcha
{
	/**
	 * @var string reCAPTCHA key
	 */
	private $key;
	/**
	 * @var string reCAPTCHA secret
	 */
	private $secret;

	/**
	 * @param string $key
	 * @param string $secret
	 */
	public function __construct(string $key, string $secret)
	{
		$this->key = $key;
		$this->secret = $secret;

		add_filter('happyforms_validate_submission', [$this, 'validateSubmission'], 10, 3);
		add_action('wp_head', [$this, 'recaptchaLoader'], 10, 0);
		add_action('happyforms_form_open', [$this, 'recaptchaHolder'], 10, 0);
	}

	/**
	 * @param $isValid
	 * @param $request
	 * @param $form
	 * @return bool
	 */
	public function validateSubmission($isValid, $request, $form)
	{
		if (isset($_POST['g-recaptcha-response'])) {
			$captcha = $_POST['g-recaptcha-response'];
		} else {
			$captcha = false;
		}

		$remoteIp = $_SERVER['REMOTE_ADDR'] ?? '';

		if (false !== $captcha) {
			$response = file_get_contents(
				"https://www.google.com/recaptcha/api/siteverify?secret=" . $this->secret . "&response=" . $captcha . "&remoteip=" . $remoteIp
			);

			$response = json_decode($response);

			return $response->success && $isValid;
		}

		return false;
	}

	/**
	 * @return void
	 */
	public function recaptchaLoader()
	{
		?>
        <script src="https://www.google.com/recaptcha/api.js?render=<?php echo $this->key; ?>"></script>
        <script>
			grecaptcha.ready(function () {
				grecaptcha.execute('<?php echo $this->key; ?>', {action: 'validate_captcha'})
					.then(function (token) {
						document.getElementById('g-recaptcha-response').value = token;
					});
			});
        </script>
		<?php
	}

	/**
	 * @return void
	 */
	public function recaptchaHolder()
	{
		?>
        <div class="" id="happyforms-recaptcha" data-happyforms-type="recaptcha" data-happyforms-id="recaptcha" data-happyforms-required="">
            <input type="hidden" id="g-recaptcha-response" name="g-recaptcha-response"/>
        </div>
		<?php
	}
}

new HappyForms_Recaptcha('KEY', 'SECRET');