Invalidate URL cache with http header

[Quintin Par]

Does hash_always_miss invalidate the cache?

- Quintin

On Wed, Jul 5, 2017 at 1:21 AM, Dridi Boukelmoune <dridi at varni.sh> wrote:

> On Wed, Jul 5, 2017 at 10:04 AM, Quintin Par <quintinpar at gmail.com> wrote:
> >
> > Nginx has a nifty command for invalidating a specific cache
> >
> > proxy_cache_bypass $http_cachepurge;
> >
> > curl -I myapp.example.com/api/ping
> <https://mailtrack.io/trace/link/034cd6cb88d2124e6aa40aa6bf29bd014db03eb8?url=http%3A%2F%2Fmyapp.example.com%2Fapi%2Fping&userId=74734&signature=64a0a6061bf36017>
> -H "cachepurge: true"
> >
> > Is there something equivalent in varnish?
>
> Hi,
>
> I'm not familiar with this nginx feature, but there is a hash_always_miss
> feature in Varnish that allows you to bypass a cache hit.
>
> You can probably do something like this in vcl_recv{}, I haven't tried:
>
>     set req.hash_always_miss = req.http.cachepurge == "true";
>
> However, this opens a DoS vector so you probably want to restrict this
> using an ACL or other means.
>
> Dridi
>
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