call

# File actionpack/lib/action_dispatch/middleware/public_exceptions.rb, line 9
    def call(env)
      status       = env["PATH_INFO"][1..-1]
      request      = ActionDispatch::Request.new(env)
      body         = { :status => status, :error => Rack::Utils::HTTP_STATUS_CODES.fetch(status.to_i, Rack::Utils::HTTP_STATUS_CODES[500]) }
      content_type = begin
                       request.formats.first
                     rescue ActionController::BadRequest
                       Mime::HTML
                     end

      render(status, content_type, body)
    end