Implementation Example in PHP

<?php

/**
 * Vev Examples - Webhook endpoint
 *
 * PHP example script for receiving PUBLISH events from Vev securely.
 *
 * [Read more here](https://help.vev.design/hosting/custom/webhook)
 */

const VEV_SECRET = 'fd718eb4-4498-4ed4-a73e-825fb1fedb13';

if (!isset($_SERVER['HTTP_X_VEV_SIGNATURE'])) {

    http_response_code(401);
    
    return 'Missing signature';

}

$signatureHeader = $_SERVER['HTTP_X_VEV_SIGNATURE'];

if (!$signatureHeader) {

    http_response_code(401);
    
    return 'Missing signature';

}

list($algorithm, $signature) = explode('=', $signatureHeader);

if (!$algorithm || !$signature) {

    http_response_code(401);
    
    return 'Invalid signature';

}

if (!in_array($algorithm, hash_hmac_algos())) {

    http_response_code(401);
    
    return 'Invalid algorithm';

}

$rawRequestBody = file_get_contents('php://input');

$requestBody = json_decode($rawRequestBody);

// Validating signature of request
// Done by comparing the signature with HMAC (hash-based message authentication code)) using the secret key for hasing
$generatedSignature = hash_hmac($algorithm, $rawRequestBody, VEV_SECRET);

// Comparing the request signature with the generated
// This will validate that the sender knows the secret and that the content was not tampered with
if ($generatedSignature !== $signature) {

    http_response_code(401);

    return 'Invalid signature';

}

$ip = $_SERVER['REMOTE_ADDR'];

if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) $ip = $_SERVER['HTTP_X_FORWARDED_FOR'];
if (!empty($_SERVER['HTTP_CLIENT_IP'])) $ip = $_SERVER['HTTP_CLIENT_IP'];

function storeVevPage ($page) {

    // Putting the files in the public dir
    // if page is index page then set the path to be public/index.html
    $pagePath = './public' . ($page->index ? '/index.html' : $page->path);

    if (!pathinfo($pagePath)['extension']) $pagePath .= '/index.html';

    $directory = substr($pagePath, 0, strrpos($pagePath, '/') - 1);

    if (!file_exists($directory)) mkdir($directory, 0777, true);

    // Writing the file to the page path
    file_put_contents($pagePath, $page->html);

}

$payload = $requestBody->payload;
$event = $requestBody->event;

switch ($event) {

    case 'PUBLISH':

        foreach ($payload->pages as $page) {

            storeVevPage($page);

        }

        echo 'I received your webhook';

    break;

    case 'PING':

        echo "Webhook test ping received from {$ip}";

    break;

}