require "rack"

def pp(hash)
  hash["HTTP_ACCEPT"].include?("text/html") ? pp_html(hash) : pp_plain(hash)
end

def pp_plain(hash)
  hash.map {|key,value| "#{key}: #{value}"}.sort.join("\n")
end

def pp_html(hash)
  hash.map {|key,value| CGI::escapeHTML("#{key}: #{value}")}.sort.join("<br/>")
end

def headers(hash)
  headers = {}
  headers['Content-Type'] = 'text/html' if hash["HTTP_ACCEPT"].include?("text/html")
  headers
end

Rack::Handler::WEBrick.run lambda {|env| [200,headers(env),[pp(env)]]} , :Port=>3000

# credits to: https://stackoverflow.com/a/17396721/520567