Streaming architecture

The Go server owns authorization and byte-range behavior. The Expo client supplies the authenticated media URL to the native audio player.

Go serverExpo client

Go server

func media(w http.ResponseWriter, r *http.Request) {
    file, meta, err := store.Open(r.Context(), actor(r), mediaID(r))
    if err != nil {
        http.Error(w, "media unavailable", http.StatusNotFound)
        return
    }
    defer file.Close()
    http.ServeContent(w, r, meta.Name, meta.Modified, file)
}

Expo client

export async function playableMediaURL(mediaID: string) {
  const token = await authToken();
  return {
    uri: `${apiBaseURL}/api/v1/media/${mediaID}`,
    headers: { Authorization: `Bearer ${token}` },
  };
}

Why byte ranges matter

Native players seek by requesting only the required part of a large audiobook. http.ServeContent implements standard range responses without a custom streaming abstraction.