I’m developing a small Onebox plugin and testing it in my production install.
It appears that Discourse is caching the Oneboxes: When I paste a link I once saw oneboxed into a new post, the preview is still looking as if it was generated by an older version of the plugin, while newer links appear as they should. All this is happening in the preview, I’m not actually posting the link.
How can I clear this cache?
Adding a rando querystring is usually the best quick & dirty way.
Yes, that works – but only to circumvent the cache for testing, not to clear it for end users.
Is there a way to really purge this cache? Does it expire eventually?
There’s always the 
option to redis-cli flushall.
Yup, it’ll automatically expire after 24 hours.
Great – this helps a lot. Thanks!
all the caches!
Be aware that flushing redis will clear sidekiq’s queue (and thus might end up losing some email notifications)
Dans l’interface en ligne de commande de Redis, vous pouvez également supprimer des clés individuelles sans vider tout le cache Redis :
# ./launcher enter app
# redis-cli
> keys *CACHE:onebox*example.com*
1) `"default: CACHE:onebox__https://example.com/"`
> del "default: CACHE:onebox__https://example.com/"
(integer) 1
> keys *CACHE:onebox*example.com*
(empty list or set)
Je suppose que ce schéma de clés changera rarement, mais si c’est le cas, vous pouvez simplement utiliser keys *onebox*url* ou même keys *url* pour rechercher la clé mise en cache à supprimer…
Je peux confirmer que j’ai supprimé avec succès des oneboxes mises en cache et reconstruit le HTML pour les publications affectées par des données corrompues mises en cache en utilisant cette méthode.