How to set Cache-Control for images?

Support Installation & Hosting
1

All the images served by Grav have “Cache-Control: no-cache” on them. This gives us a bad performance rating. The configuration documentation suggests you could set the cache_control setting, but I’ve tried cache_control: 'private, max-age=31536000' but that doesn’t do anything. I actually doubt if that is still a valid configuration parameter, since it was not included by default in my system.yaml.

How do I set the cache control instructions correctly? And should I do that in Grav at all or in Nginx?

Thanks,

Pascal

2

In my system.yaml there is a section for this:

    images:
  default_image_quality: 85
  cache_all: true
  cache_perms: '0755'
  debug: true
  auto_fix_orientation: true

Is it in yours?

3

Yes, it is, but that does not affect cache-control settings. In addition, cache-control settings do not only apply to images, but also to other assets, like JS and CSS files. So there should be a way to cover this as well. It’s unfortunate and strange that this isn’t documented anywhere, since this is very important for performance and performance rankings.

4

I’ve decided to try and see if NGINX could be used to set the proper cache-control. I ran into this sample NGINX config file and used the rules for assets, images and fonts to add cache-control headers to the responses. That works! I still would like to know if this is the preferred way of doing this with Grav (and NGINX). And if so, I think it would be very valuable is this was added to the documentation somewhere.

5

same here. Lighthouse Report says: “Serve static assets with an efficient cache policy”. Same settings in grav like plind and webfed, no change. Images and .js files are affected. Thx4help

6

Jup, it seems like, Grav does only apply the cache control to the pages, but not media files and or assets. It would be really great, if Grav would support that!

7

@manfredsteger, @NEA , I’m not that well versed on infrastructural matters, but as far as I know, and correct me if I’m wrong:

  • Grav only serves pages and can therefor set appropriate cache-control headers in the response.
  • Grav doesn’t do anything to serve images and assets (.js, .css).
    These are served by the webserver, no interference from Grav. Hence Grav cannot add any cache-control settings to the headers.
  • cache-control for images and assets should therefor be set in .htaccess, for example:
    # One year for image files
<filesMatch ".(jpg|jpeg|png|gif|ico)$">
   Header set Cache-Control "max-age=31536000, public"
</filesMatch>
# One month for css and js
<filesMatch ".(css|js)$">
   Header set Cache-Control "max-age=2678400, public"
</filesMatch>
    Lighthouse will report it is happy wrt. the cache policy of static assets…

Some documents on this topic I like:

Any improvement/corrections on my thinking is welcome!

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