Last active

Embed URL

HTTPS clone URL

SSH clone URL

You can clone with HTTPS or SSH.

Download Gist

Apache: Detecting WebP support with Header Vary Accept

View .htaccess
1 2 3 4 5 6 7 8 9 10 11 12
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_ACCEPT} image/webp
RewriteCond %{DOCUMENT_ROOT}/$1.webp -f
RewriteRule (.+)\.(jpe?g|png)$ $1.webp [T=image/webp,E=accept:1]
</IfModule>
 
<IfModule mod_headers.c>
Header append Vary Accept env=REDIRECT_accept
</IfModule>
 
AddType image/webp .webp
Owner

The code is implemented on http://cup.wpcoder.de

I see that you're adding 'Accept' to the Vary header, which is great, but you're also varying the content based on the User-Agent, so that would have to be included in the Vary header for it to be correct.

Fortunately Chrome is now sending "image/webp" in the Accept header for image requests, (although not on html requests unfortunately) so you should be able to remove the User-Agent detection. Users will get the webp version for resources included on a page, but not if they request the image directly.

Sergej: Just checked your website, but in the latest Chrome Beta I see PNG's. Is this .htacess not working any more?

@MusikDK
Look: http://d.pr/i/DUF1

Sorry I didn't see your link in time as its expired. When I check in Chrome 35 Beta (osx) its still PNG's your site is serving.

@MusikDK, you probably see a .png files because that's what the URL in the page points to. But the server is serving an webp image "disguised" as a file with extension .png. It's an internal rewrite.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Something went wrong with that request. Please try again.