Session Cache Limiter
The Last-Modified header...
Besides server-side caching that we have described in the previous sections, Web applications may also exploit client-side caching to save the time for generating and transmitting the same page content.
To use client-side caching, you may configure [[yii\filters\HttpCache]] as a filter for controller actions whose rendering result may be cached on the client-side. [[yii\filters\HttpCache|HttpCache]] only works for
HEAD requests. It can handle three kinds of cache-related HTTP headers for these requests: