public function handle($data)
{
$this->validate_request(["username", "password"]);
$username = $data->{"username"};
$displayname = $username;
if (isset($data->{"display-name"})) {
$displayname = $data->{"display-name"};
}
if (UserBackend::user_exists($username)) {
throw new EndpointExecutionException("User already exists", ["username" => $username]);
}
// Create their entry in the user database
$profile = UserBackend::create_user($username, $displayname, $data->{"password"});
// Return the new user to the client
return ["user" => $profile->toExternalForm()];
}
