Speed Tips: Remove Last-Modified Header

BTW...auto-playing music is a good way to lose traffic. Is this a MySpace page?

This is what I currently have in my .htaccess file at the root. Do you see any problems with what I have here?

First off, once your rules are correct be sure to move the rules out of .htaccess and into the httpd.conf file for the Directory section of your DocumentRoot. Why? .htaccess is inherently slow as it must be read for each and every request that starts in or goes deeper than the directory in which it resides (and for which AllowOverride is enabled).

See the Apache documentation for .htaccess files for more information

Information isn't valid. Existence of Last-Modified / ETag doesn't influence rate of cache integtiry checks in browsers

Having some issues with pagespeed (aka google's analysis tool). It's saying I need to specify a last-modified header, but the htaccess file has the following:

ErrorDocument 401 http://www.site.co.uk/401-page.html
ErrorDocument 404 http://www.site.co.uk/404-page.html
ErrorDocument 500 http://www.site.co.uk/500-page.html
 
RewriteEngine On
RewriteCond %{HTTP_HOST} ^site.co.uk [nc]
RewriteRule (.*) http://www.site.co.uk/$1 [R=301,L]
 
ExpiresActive On
ExpiresByType image/ico A29030400
ExpiresByType image/gif A2592000
ExpiresByType image/png A2592000
ExpiresByType image/jpg A2592000
ExpiresByType image/jpeg A2592000
ExpiresByType text/javascript A2592000
ExpiresByType text/css A2592000
ExpiresByType text/swf A29030400
ExpiresByType text/js A29030400
 
Header add X-Enabled mod_gzip
Header add X-Enabled mod_deflate
Header set Cache-Control "private"
Header set Expires "Thu, 27 Jul 2011 10:00:00 GMT"
 
FileETag none
 
Header unset Last-Modified

Is the file correct - are there clashes/ etc. Current pagespeed score is 91% and yslow gives it a Grade A. Before I move on to learning about CDN's, I need to make sure I'm on the right track with htaccess files!

I found this tip valuable until today... when I realize that it is not complete.

Removing the ETag header is ok (each server generate a different ETag, in a cluster/farm this will be a problem, not a solution). But by removing the last-modified header you will make the browser use the "Expires" only, when the content Expires on browser cache it (the browser) will fetch a new content, regardless if is modified or not. If you use Expires and last-modified together, the browser (firefox on my test, YMMV) use the Expires, and after that it start to use last-modified getting the 304 (not modified) as a benefit. This way you get a two layer of cache: 1- absolutely local, 2- Browser e Server if-modified-since/not-modified handshake;

Klaubert

David this is not true anymore!

new browsere ( ie8 , firefox, chrome) ask again the resource if they do not know when was last modified!

so this article should be changed since make damages

I agree with David Merrilees's comment below.

Removing the Last-Modified header seems totally useless. I tested on Firefox with "FireBug > Net" (Firefox versions 3.6 and 11.0)

If you close the browsers and re-open it, and then you navigate to the page you previously viewed, you will see browser hitting the server with an HTTP request for each resource (images, etc.).

After the HTTP request, the server replies with 200 OK and the browser decides to take the image from cache instead of downloading it from server, but the browser has still inquired the server for each image with an HTTP request, so it's NOT true when in this article they say: "...this is a really unique trick I promise) eliminate any validation requests!!"

FYI: this issue was discussed also on stackoverflow: because the same problem arises even when using Cache-Control: max-age=31536000 header.

Unfortunately, it's rather clear from the synopsis of this article that the author doesn't understand caching properly, nor the actual implications of disabling cache validators (that is, ETag and Last-Modified).

As with other commentators, I strongly suggest that this article should at least be ignored, but better would be for the author to remove or rewrite it. For better information, search for Mark Nottingham's caching tutorial.