how to get HTTPS headers from webhook requester

Question

I have a webhook to receive updates that I am trying to configure. I need to get the bearer token from the header, but I am not able to retrieve it. Can someone shed some light on this issue? I am stumped!

receiving url is https://example.com/receive

$data = file_get_contents("php://input",true);
$events= json_decode($data, true);

Answer 1

If you're looking for an OAuth bearer token these are usually transferred in the request HTTP Authorization header. In PHP these can be a little tricky to read since different web servers have different approaches to reading the Authorization header.

There's a good example of how to read a bearer token in this answer. Copied here for convenience:

<?PHP
/** 
 * Get hearder Authorization
 * */
function getAuthorizationHeader() {
    $headers = null;
    if (isset($_SERVER['Authorization'])) {
        $headers = trim($_SERVER["Authorization"]);
    } else if (isset($_SERVER['HTTP_AUTHORIZATION'])) { //Nginx or fast CGI
        $headers = trim($_SERVER["HTTP_AUTHORIZATION"]);
    } elseif (function_exists('apache_request_headers')) {
        $requestHeaders = apache_request_headers();
        // Server-side fix for bug in old Android versions (a nice side-effect of this fix means we don't care about capitalization for Authorization)
        $requestHeaders = array_combine(array_map('ucwords', array_keys($requestHeaders)), array_values($requestHeaders));
        if (isset($requestHeaders['Authorization'])) {
            $headers = trim($requestHeaders['Authorization']);
        }
    }
    return $headers;
}
/**
 * get access token from header
 * */
function getBearerToken() {
    $headers = getAuthorizationHeader();
    // HEADER: Get the access token from the header
    if (!empty($headers)) {
        if (preg_match('/Bearer\s(\S+)/', $headers, $matches)) {
            return $matches[1];
        }
    }
    return null;
}
?>