def build_preview_url(sig_base64, url_base64, filename \\ nil, preview_params \\ []) do
uri = proxy_url("proxy/preview", sig_base64, url_base64, filename)
def build_preview_url(sig_base64, url_base64, filename \\ nil, preview_params \\ []) do
uri = proxy_url("proxy/preview", sig_base64, url_base64, filename)