HTTP conditional GET

[Meng]

Hello,

I have just test my website with bing's tools: http://www.microsoft.com/search/Tools/default.aspx
The test result is



HTTP compression and conditional GET results

    URL: http://www.shijile.com

    HTTP status code: 200 OK

    HTTP conditional GET: not enabled for the date selected
    HTTP compression enabled using gzip

    HTTP headers:

        Transfer-Encoding: chunked
        Connection: keep-alive
        Pragma: no-cache
        Cache-Control: max-age=86400,private
        Content-Type: text/html
        Date: Sat, 01 Aug 2009 12:57:43 GMT
        Expires: Sun, 02 Aug 2009 12:57:43 GMT
        Set-Cookie: PHPSESSID=e86i00j7mn1f88jm6mqlogjqd6; path=/
        Server: nginx/0.7.61
        X-Powered-By: PHP/5.1.6
        Content-Encoding: gzip


For more information
Find the information you need to enhance your website with HTTP compression and conditional GET:
Blog: Announcing Crawler Improvements for bing
Blog: Optimizing your very large site for search - Part 2
Webmaster Center



I am curious about this info:  HTTP conditional GET not enabled. It is said that HTTP conditional GET will greatly improve the website performance.
I have searched Nginx wiki and this forum but get no result for this feature. Is there any setting equivalent to enable HTTP conditional GET? Or Nginx will implement it in the future?

Thanks

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,4669,4669#msg-4669