Client caching and gzip settings not working

Question

I am trying to optimize image, js, and css delivery by enabling gzip compression and setting the client cache policy. The issue is, it doesn't seem like any of the settings are being used. Here is the settings I am trying to use

<caching>
  <profiles>
    <add extension=".js" policy="CacheForTimePeriod" kernelCachePolicy="CacheForTimePeriod" duration="21.00:00:00"/>
    <add extension=".css" policy="CacheForTimePeriod" kernelCachePolicy="CacheForTimePeriod" duration="21.00:00:00"/>
    <add extension=".png" policy="CacheForTimePeriod" kernelCachePolicy="CacheForTimePeriod" duration="21.00:00:00"/>
    <add extension=".svg" policy="CacheForTimePeriod" kernelCachePolicy="CacheForTimePeriod" duration="21.00:00:00"/>
    <add extension=".jpg" policy="CacheForTimePeriod" kernelCachePolicy="CacheForTimePeriod" duration="21.00:00:00"/>
  </profiles>
</caching>
<httpCompression directory="%SystemDrive%\inetpub\temp\IIS Temporary Compressed Files"
        staticCompressionDisableCpuUsage="95" staticCompressionEnableCpuUsage="60"
        dynamicCompressionDisableCpuUsage="95" dynamicCompressionEnableCpuUsage="50">
  <scheme name="gzip" dll="%Windir%\system32\inetsrv\gzip.dll" staticCompressionLevel="9" />
  <dynamicTypes>
    <add mimeType="text/*" enabled="true" />
    <add mimeType="image/*" enabled="true" />
    <add mimeType="message/*" enabled="true" />
    <add mimeType="application/x-javascript" enabled="true" />
    <add mimeType="*/*" enabled="false" />
    <add mimeType="application/json" enabled="true" />
    <add mimeType="application/json; charset=utf-8" enabled="true" />
  </dynamicTypes>
  <staticTypes>
    <add mimeType="text/*" enabled="true" />
    <add mimeType="image/*" enabled="true" />
    <add mimeType="message/*" enabled="true" />
    <add mimeType="application/x-javascript" enabled="true" />
    <add mimeType="application/atom+xml" enabled="true" />
    <add mimeType="application/xaml+xml" enabled="true" />
    <add mimeType="application/json" enabled="true" />
    <add mimeType="application/json; charset=utf-8" enabled="true" />
    <add mimeType="*/*" enabled="false" />
  </staticTypes>
</httpCompression>
<urlCompression doStaticCompression="true" doDynamicCompression="true"/>

Client Caching

I have specified 21 days caching for js, css, png, svg, and jpg. When I examine the headers for images stored in the Media Library the expires header is set to 7 days, and anything served from the file system has cache-control set to no-cache. Nothing I do changes this

Compression

CSS and JS files are being compressed, but png and svg files are not

What am I missing here? Are there Sitecore settings that might be interfering with IIS?

Answer 1

To optimize images in the media library I recommend using Dianoga from the mind of @kamsar - it optimizes the image files after they are added into the media cache as an async process. So it doesn't affect the front end response times.

This can cause issues if you want to make sure images are cached on the client or if you are using a CDN, but you can change the async in to a synchronous call so that the CDN or browser will instantly get the optimized file. In those cases, you may want to consider a warm up script to prevent users from seeing the first hit delay as it processes the media.

Answer 2

I had a partly related question myself a few days ago How to configure caching for static resources in Sitecore

It turned out that my problem was forgetting to do a hard-refresh (CTRL + SHIFT+R) in the browser!

BTW I found that the <caching>...</caching> section in web.config broke Sitecore completely.