Rack::ShowStatus catches all empty responses and replaces them with a site explaining the error.

Additional details can be put into rack.showstatus.detail and will be shown as HTML. If such details exist, the error page is always rendered, even if the reply was not empty.

Methods
C
N
Class Public methods
new(app)
# File lib/rack/show_status.rb, line 14
def initialize(app)
  @app = app
  @template = ERB.new(TEMPLATE)
end
Instance Public methods
call(env)
# File lib/rack/show_status.rb, line 19
def call(env)
  status, headers, body = @app.call(env)
  headers = Utils::HeaderHash.new(headers)
  empty = headers[CONTENT_LENGTH].to_i <= 0

  # client or server error, or explicit message
  if (status.to_i >= 400 && empty) || env[RACK_SHOWSTATUS_DETAIL]
    # This double assignment is to prevent an "unused variable" warning on
    # Ruby 1.9.3.  Yes, it is dumb, but I don't like Ruby yelling at me.
    req = req = Rack::Request.new(env)

    message = Rack::Utils::HTTP_STATUS_CODES[status.to_i] || status.to_s

    # This double assignment is to prevent an "unused variable" warning on
    # Ruby 1.9.3.  Yes, it is dumb, but I don't like Ruby yelling at me.
    detail = detail = env[RACK_SHOWSTATUS_DETAIL] || message

    body = @template.result(binding)
    size = body.bytesize
    [status, headers.merge(CONTENT_TYPE => "text/html", CONTENT_LENGTH => size.to_s), [body]]
  else
    [status, headers, body]
  end
end