pokap/webhook.php

## webhook.php
<?php

const FILE_LOG = 'webhook.log';

ensure_log_access();

switch ($_SERVER['REQUEST_METHOD']) {
    case 'HEAD':
        add_log("Subscription works!");

        send_headers_and_exit(200, 'OK', ['X-Webhook-Secret' => $_SERVER['HTTP_X_WEBHOOK_SECRET']]);
        break;

    case 'POST':
        $requestContent = file_get_contents('php://input');

        add_log($requestContent);

        send_headers_and_exit(200, 'OK');
        break;

    case 'GET':
        if (isset($_GET['action']) && $_GET['action'] === 'purge') {
            purge_logs();
        }

        $logs = get_logs();

        print "<!DOCTYPE html>
<html>
<head>
 <title>Webhook</title>
</head>
<body>
<h1>Logs</h1>
<pre>{$logs}</pre>
</body>
</html>";
        break;
}

exit(0);

// ---------------------------------------------------------------------------------------------------------------------

function send_headers_and_exit($statusCode, $statusText, array $headers = []) {
    foreach ($headers as $name => $value) {
        header("{$name}: {$value}", false, $statusCode);
    }

    header("HTTP/1.1 {$statusCode} {$statusText}", true, $statusCode);
    exit(0);
}

function ensure_log_access() {
    if (!file_exists(FILE_LOG)) {
        touch(FILE_LOG);
    }
}

function add_log($message) {
    $date = new \DateTime('now', new \DateTimeZone('UTC'));

    $message = str_replace("\n", "\n\t", $message);

    file_put_contents(FILE_LOG, "[{$date->format(DATE_RFC3339)}]\n\t{$message}\n", FILE_APPEND);
}

function get_logs() {
    return file_get_contents(FILE_LOG);
}

function purge_logs() {
    file_put_contents(FILE_LOG, '');
}
	<?php

	const FILE_LOG = 'webhook.log';

	ensure_log_access();

	switch ($_SERVER['REQUEST_METHOD']) {
	case 'HEAD':
	add_log("Subscription works!");

	send_headers_and_exit(200, 'OK', ['X-Webhook-Secret' => $_SERVER['HTTP_X_WEBHOOK_SECRET']]);
	break;

	case 'POST':
	$requestContent = file_get_contents('php://input');

	add_log($requestContent);

	send_headers_and_exit(200, 'OK');
	break;

	case 'GET':
	if (isset($_GET['action']) && $_GET['action'] === 'purge') {
	purge_logs();
	}

	$logs = get_logs();

	print "<!DOCTYPE html>
	<html>
	<head>
	<title>Webhook</title>
	</head>
	<body>
	<h1>Logs</h1>
	<pre>{$logs}</pre>
	</body>
	</html>";
	break;
	}

	exit(0);

	// ---------------------------------------------------------------------------------------------------------------------

	function send_headers_and_exit($statusCode, $statusText, array $headers = []) {
	foreach ($headers as $name => $value) {
	header("{$name}: {$value}", false, $statusCode);
	}

	header("HTTP/1.1 {$statusCode} {$statusText}", true, $statusCode);
	exit(0);
	}

	function ensure_log_access() {
	if (!file_exists(FILE_LOG)) {
	touch(FILE_LOG);
	}
	}

	function add_log($message) {
	$date = new \DateTime('now', new \DateTimeZone('UTC'));

	$message = str_replace("\n", "\n\t", $message);

	file_put_contents(FILE_LOG, "[{$date->format(DATE_RFC3339)}]\n\t{$message}\n", FILE_APPEND);
	}

	function get_logs() {
	return file_get_contents(FILE_LOG);
	}

	function purge_logs() {
	file_put_contents(FILE_LOG, '');
	}