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

<?php

class ReportActions extends Actions
{
  public static function executeDmca()
  {
    Response::setHeader(Response::HEADER_CROSS_ORIGIN, "*");
    if (!Request::isPost())
    {
      return ['report/dmca'];
    }

    $values = [];
    $errors = [];

    foreach (['name', 'email', 'rightsholder', 'identifier'] as $field)
    {
      $value = Request::getPostParam($field);

      if (!$value)
      {
        $errors[$field] = __('form_error.required');
      }
      elseif($field == 'email' && !filter_var($value, FILTER_VALIDATE_EMAIL))
      {
        $errors[$field] = __('form_error.invalid');
      }

      $values[$field] = $value;
    }

    if (!$errors)
    {
      $values['report_id'] = Encoding::base58Encode(random_bytes(6));
      Mailgun::sendDmcaReport($values);
      Session::setFlash('success', '<h3>Report Submitted</h3><p>We will respond shortly.</p><p>This ID for this report is <strong>' . $values['report_id'] . '</strong>. Please reference this ID when contacting us regarding this report.</p>');
      return Controller::redirect(Request::getRelativeUri(), 303);
    }

    return ['report/dmca', ['errors' => $errors, 'values' => $values]];
  }
}