https://qooah.com/2016/04/13/facebook-%e9%87%8b%e5%87%ba-messenger-%e8%81%8a%e5%a4%a9%e6%a9%9f%e5%99%a8%e4%ba%ba-api%ef%bc%8c%e7%94%a8%e4%ba%ba%e5%b7%a5%e6%99%ba%e6%85%a7%e8%88%87%e4%bd%bf%e7%94%a8%e8%80%85%e4%ba%92%e5%8b%95/