Cache Invalidation

[Dridi Boukelmoune]

> I am new to Varnish. Could you please provide an example (detailed one would
> be nice) for the following approach you suggested?

I can't give you a detailed example, but I suggest you have a look at
the documentation for the grace [1] mode, how to set it [2] via
Cache-Control. The Varnish Book also covers HTTP [3] in one chapter,
you'll learn more about conditional requests.

Cheers

[1] https://www.varnish-cache.org/docs/4.1/users-guide/vcl-grace.html
[2] https://www.varnish-cache.org/docs/4.1/whats-new/changes.html?highlight=grace#other-noteworthy-small-changes
[3] http://book.varnish-software.com/4.0/chapters/HTTP.html