Maintaining 65k open connections in a single Ruby process

In the Ruby world, the Rack protocol is the specification for how web servers should communicate with applications. In the core it is quite simple: an application is an object that responds to the call method, taking the environment hash as a parameter, and returning an Array with three elements. It will be called for every HTTP request. The ‘environment’ mentioned is a giant hash containing all the parameters like the HTTP method, the path requested, the request headers, etc.