How to upload a file to a ruby ​​web application without frameworks?

Question

ruby

Good afternoon, I need to write a simple web application that would process a text file sent to a ruby ​​server. Is there a simple way to implement such a service without the need for redundant frameworks like Rails? Ideally, it should be one file connecting the necessary gems and displaying a page with file indicators?

Answer 1

Rack
Of the minimalistic frameworks, I recommend Sinatra