inspect-headers.herokuapp.com – prints HTTP request headers (an excuse to try out heroku cedar)

config.ru

require "stringio"
require "bundler"

Bundler.require

run ->(env) {
  body = StringIO.new
  
  env.sort.each do |(k, v)|
    next unless k =~ /^HTTP_(\w+)/
    header = $1.split("_").map(&:capitalize).join("-")
    body.puts "#{header}: #{v}"
  end

  body.rewind

  [200, { "Content-Type" => "text/plain" }, body]
}

Gemfile

source :rubygems

gem "rack", "~> 1.3.0"
gem "thin", "~> 1.2.7"

Gemfile.lock

GEM
  remote: http://rubygems.org/
  specs:
    daemons (1.1.0)
    eventmachine (0.12.10)
    rack (1.3.0)
    thin (1.2.11)
      daemons (>= 1.0.9)
      eventmachine (>= 0.12.6)
      rack (>= 1.0.0)

PLATFORMS
  ruby

DEPENDENCIES
  rack (~> 1.3.0)
  thin (~> 1.2.7)

Procfile

web: bundle exec thin start -p $PORT