lbry.com/controller/action/MailActions.class.php

<?php

class MailActions extends Actions
{
    public static function executeSubscribe()
    {
        if (!Request::isPost()) {
            return ['mail/subscribe'];
        }

        $nextUrl = Request::getPostParam('returnUrl', '/');
        if (!$nextUrl || $nextUrl[0] != '/' || !filter_var($nextUrl, FILTER_VALIDATE_URL)) {
            $nextUrl = '/';
        }

        $email = Request::getPostParam('email');
        if (!$email || !filter_var($email, FILTER_VALIDATE_EMAIL)) {
            Session::set(
          Session::KEY_LIST_SUB_ERROR,
        $email ? __('Please provide a valid email address.') : __('Please provide an email address.')
      );

            return Controller::redirect(Request::getRelativeUri());
        }

        $tag = Request::getPostParam('tag');

        $response = LBRY::subscribe($email, $tag);
        if ($response['error']) {
            return ['mail/subscribe', ['error' => $response['error']]];
        }

        return ['mail/subscribe', ['subscribeSuccess' => true, 'nextUrl' => $nextUrl]];
    }

    public static function executeSubscribed()
    {
        return ['mail/subscribe', ['confirmSuccess' => true, 'learnFooter' => true]];
    }


    public static function prepareSubscribeFormPartial(array $vars)
    {
        $vars += ['btnClass' => 'btn-primary', 'returnUrl' => Request::getRelativeUri()];

        $vars['error'] = Session::get(Session::KEY_LIST_SUB_ERROR);
        Session::unsetKey(Session::KEY_LIST_SUB_ERROR);

        return $vars;
    }

    public static function executeUnsubscribe(string $email)
    {
        Response::disableHttpCache();
        $decodedEmail = Encoding::base64DecodeUrlsafe(urldecode($email));
        if (!$decodedEmail) {
            return ['mail/unsubscribe', ['error' => 'Invalid unsubscribe link']];
        }

        $response = LBRY::unsubscribe($decodedEmail);
        return ['mail/unsubscribe', ['error' => $response['error']]];
    }

    public static function editEmailSettings(string $token)
    {
        Response::disableHttpCache();
        list($status, $headers, $response) = LBRY::emailStatus($token);
        if ($status == 403) {
            //Catch 403 to return elegant error message.
            $response['error'] = "This email link is invalid. If you clicked this from an older email it may have been expired for security purposes. Please email help@lbry.com for a valid one.";
        }
        $responseData = $response['data'] ?? [];
        return ['mail/settings', [
          'emails' => $responseData['emails'] ?? [],
          'tags' => $responseData['tags'] ?? [],
          'token' => $token,
          'error' => $response['error'] ?? false
        ]];
    }

    public static function prepareSettingsFormPartial(array $vars)
    {
      $tags = LBRY::listTags($vars['token']);
      $tagMetadata = [];
      $specialDisplayNames = [
        'ios' => 'iOS'
      ];
      foreach($tags as $tag) {
        if ($tag['is_user_addable']) {
          $tagMetadata[$tag['name']] = [
            'label' => $specialDisplayNames[$tag['name']] ?? ucwords(str_replace(['-', '_'], ' ', $tag['name'])),
            'description' => $tag['description']
          ];
        }
      }
      return $vars + ['tagMetadata' => $tagMetadata];
    }
}