原理很简单:
https://www.cnblogs.com/weiguang3100/p/4342233.html
离线IP数据库文件:
https://lite.ip2location.com/database-ip-country-region-city-latitude-longitude-zipcode-timezone
GO会用到:
https://blog.csdn.net/a_ran/article/details/78875768
https://xiequan.info/%E4%BD%BF%E7%94%A8go%E8%AF%AD%E8%A8%80%E6%A0%87%E5%87%86%E5%BA%93%E5%AF%B9csv%E6%96%87%E4%BB%B6%E8%BF%9B%E8%A1%8C%E8%AF%BB%E5%86%99/
Redis Sorted-Set类型操作
https://www.cnblogs.com/stephen-liu74/archive/2012/03/23/2354994.html