Refile is a modern file upload library for Ruby applications. It is simple, yet powerful. Refile is an attempt by CarrierWave's original author to fix the design mistakes and overengineering in CarrierWave.

https://github.com/elabs/refile

目测，一大波国内云的 refile backends 正在接近

其实我觉得各大云厂商搞一份自己的 Fog Provider 就 基本够用了，不用冒出那么多

upload_gem-aaa upload_gem-bbb upload_gem-ccc

http://fog.io/about/provider_documentation.html