What is the “env” variable in Rack middleware?

Question

I know a Rack middleware filter is a Ruby class with an initialize and a call method. I know the call method takes an \"env\" argument. Something like this:

Answer 1

I suggest that you can try to print the 'env' variable with writing a simple programming.

require "rubygems"
require "rack" 
def pp(hash)
  hash.map {|key,value| "#{key} => #{value}"}.sort.join("
") 
end
Rack::Handler::WEBrick.run lambda {|env| [200,{},[pp(env)]]} , :Port=>3000

enter the link localhost:3000