main.rb

require "sinatra"
require 'fileutils'

get '/time' do
  Time.now.to_s
end

# curl -X PUT -T foo http://localhost:3000/upload/foo
put '/upload/:file' do
  input = env["rack.input"]
  out_fname = "uploads/#{params[:file]}"

  if input.respond_to? :path
    FileUtils.cp(input.path, out_fname)
  else
    File.write(out_fname, input.read)
  end

  'uploaded'
end