Middleware to respond to HTTP HEAD /

health.rb

# Add this file to /lib/health.rb
# Require in config/application.rb
# require File.join(File.dirname(__FILE__), '../lib/health.rb')
# Load in config/application.rb
# config.middleware.use Heroku::HttpHealth
# Be sure to put this middleware at the front of all other middlewares. Don't want authentication on this guy.

class Heroku::HttpHealth
  def initialize(app)
    @app = app
  end

  def call(env)
    if env["PATH_INFO"] =~ /\A\/?\z/ && env["REQUEST_METHOD"] == "HEAD"
      [200, {"Content-Type" => "text/plain"}, ["OK"]]
    else
      @app.call(env)
    end
  end
end