sendfile_middleware.rb

module DevNull
  class FileEachWrapper
    def initialize(io)
      @io = io
    end

    def each
      
    end

    def method_missing(sym, *a, &b)
      @io.__send__(sym, *a, &b)
    end
  end

  class SendfileMiddleware
    SENDFILE_HEADER = 'X-Sendfile'

    def initialize(app)
      @app = app
    end

    def call(env)
      status, headers, body = @app.call(env)

      if headers.has_key?('X-Sendfile')
        path = body.to_path
        headers.delete(SENDFILE_HEADER)

        if defined?(::JRUBY_VERSION) and defined?(JRuby::Rack) and res.is_a?(JRuby::Rack::Response)
          body = []
          headers['Forward'] = lambda { |res| SendfileStreamer.new(status, headers, path).respond(res) }
        else
          body = File.open(path, 'r')
        end
      end

      [status, headers, body]
    end
  end

  # XXX: HACK! copy/paste from jruby-rack-1.0.5
  class SendfileStreamer
    def initialize(status, headers, path)
      @status   = status
      @headers  = headers
      @path     = path
    end

    def respond(response)
      write_status(response)
      write_headers(response)
      write_body(response)
    end

    def write_status(response)
      response.setStatus(@status.to_i)
    end

    def write_headers(response)
      @headers.each do |k,v|
        case k
        when /^Content-Type$/i
          response.setContentType(v.to_s)
        when /^Content-Length$/i
          response.setContentLength(v.to_i)
        else
          if v.respond_to?(:each_line)
            v.each_line {|val| response.addHeader(k.to_s, val.chomp("\n")) }
          elsif v.respond_to?(:each)
            v.each {|val| response.addHeader(k.to_s, val.chomp("\n")) }
          else
            case v
            when Numeric
              response.addIntHeader(k.to_s, v.to_i)
            when Time
              response.addDateHeader(k.to_s, v.to_i * 1000)
            else
              response.addHeader(k.to_s, v.to_s)
            end
          end
        end
      end
    end

    def write_body(response)
      out = java.nio.channels.Channels.newChannel(response.getOutputStream)

      File.open(@path) do |fp|
        fp.to_channel.transfer_to(0, fp.stat.size, out)
      end
    end
  end
end