safeware.rb

class Safeware

  def initialize(app)
    @app = app
  end

  # This dup pattern is used frequently to avoid race conditions on state stored
  # inside this middleware. It's not foolproof, but if you're just using
  # single-reference instance variables (instance variables with primitive
  # values (not data structures)) then it works well.
  def call(env)
    dup._call(env)
  end

  def _call(env)
    # before actions
    status, headers, body = @app.call(env)
    # after actions
    return status, headers, body
  ensure
    # If we're raising an exception, then the body from the app will not be
    # passed on to the server or any parent middleware. In order to conform to
    # the body close specification, we therefore must close it here under that
    # condition. n.b. it's possible that an exception occurs before body is set,
    # so we check for body first.
    body.close if body && body.respond_to?(:close) && $!
  end

  # TODO before and after action breakouts for the non-rack async api, with proc
  # wrappers in env.

  # TODO logging / errors integration

  # TODO input rewind example

  # ...
end

❤️ ❤️

Thanks for descriptive comments!

fwiw, referenced from airbrake/airbrake#153