function handler(event) {
  var response = event.response;
  var uri = event.request.uri;
  var query = event.request.querystring;

  var filename = uri.split("/").pop();
  
  // Override filename if query param is provided
  if (query.filename && query.filename.value) {
    filename = query.filename.value;
  }

  if (query.download && query.download.value === "true") {
    response.headers['content-disposition'] = {
      value: 'attachment; filename="' + filename + '"'
    };
  } else if (query.inline && query.inline.value === "true") {
    response.headers['content-disposition'] = {
      value: 'inline; filename="' + filename + '"'
    };
  }

  return response;
}