I would recommend using Google Recaptcha (https://www.google.com/recaptcha/intro/) instead of your own and use a third party emailer PHPMailer or Swiftmailer (I use this -> https://swiftmailer.symfony.com/)
Here an old example of a contact form that I did :
[php]<?php
require_once ‘…/private/initialize.php’;
use Library\Database\Database as DB;
use Library\Email\Email;
$db = DB::getInstance();
$pdo = $db->getConnection();
$submit = filter_input(INPUT_POST, ‘submit’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
if (isset($submit) && $submit === ‘submit’) {
$token = filter_input(INPUT_POST, ‘token’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
if (!empty($token)) {
if (hash_equals($_SESSION[‘token’], $token)) {
/* The Following to get response back from Google recaptcah /
$url = “https://www.google.com/recaptcha/api/siteverify”;
$remoteServer = filter_input(INPUT_SERVER, ‘REMOTE_ADDR’, FILTER_SANITIZE_URL);
$response = file_get_contents($url . “?secret=” . PRIVATE_KEY . “&response=” . \htmlspecialchars($_POST[‘g-recaptcha-response’]) . “&remoteip=” . $remoteServer);
$recaptcha_data = json_decode($response);
/ The actual check of the recaptcha */
if (isset($recaptcha_data->success) && $recaptcha_data->success === TRUE) {
$data[‘name’] = filter_input(INPUT_POST, ‘name’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
$data[‘email’] = filter_input(INPUT_POST, ‘email’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
$data[‘phone’] = filter_input(INPUT_POST, ‘phone’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
$data[‘website’] = filter_input(INPUT_POST, ‘website’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
$data[‘reason’] = filter_input(INPUT_POST, ‘reason’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
$data[‘comments’] = filter_input(INPUT_POST, ‘comments’, FILTER_SANITIZE_FULL_SPECIAL_CHARS);
$send = new Email($data);
} else {
$success = “You’re not a human!”; // Not of a production server:
}
} else {
// Log this as a warning and keep an eye on these attempts
}
}
}
require_once ‘…/private/includes/header.inc.php’;
?>
<fieldset>
<legend><?php echo (isset($success)) ? $success : 'Contact Form'; ?></legend>
<input type="hidden" name="token" value="<?= $_SESSION['token']; ?>">
<label for="name" accesskey="U">Name</label>
<input name="name" type="text" id="name" tabindex="1" autofocus required="required" />
<label for="email" accesskey="E">Email</label>
<input name="email" type="email" id="email" tabindex="2" required="required" />
<label for="phone" accesskey="P" >Phone <small>(optional)</small></label>
<input name="phone" type="tel" id="phone" tabindex="3">
<label for="website" accesskey="W">Website <small>(optional)</small></label>
<input name="website" type="text" id="website" tabindex="4">
<div class="radioBlock">
<input type="radio" id="radio1" name="reason" value="message" tabindex="5" checked>
<label class="radioStyle" for="radio1">message</label>
<input type="radio" id="radio2" name="reason" value="order">
<label class="radioStyle" for="radio2">order</label>
<input type="radio" id="radio3" name="reason" value="status">
<label class="radioStyle" for="radio3">status inquiry</label>
</div>
<label class="textBox" for="comments">Comments</label>
<textarea name="comments" id="comments" spellcheck="true" tabindex="6" required="required"></textarea>
<div class="g-recaptcha" data-sitekey="6LfPlQoUAAAAAPgD3PpnQ_uGTzc87UALiFgQ3XnK"></div>
<input type="submit" name="submit" value="submit" tabindex="7">
</fieldset>
</form>
<?php
require_once '../private/includes/footer.inc.php';[/php]
You can find more here https://github.com/Strider64/Slice-of-Technology which is a Github Repository that I have done.
