Problem Statement

This task   (the reverse of   URL encoding   and distinct from   URL parser)   is to provide a function or mechanism to convert an URL-encoded string into its original unencoded form.

Let's start with the solution:

require "uri"

puts URI.decode "http%3A%2F%2Ffoo%20bar%2F"
puts URI.decode "google.com/search?q=%60Abdu%27l-Bah%C3%A1"