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)
No CLI do Redis, você também pode excluir chaves individuais sem limpar todo o cache do 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)
Espero que esse esquema de chaves não mude com frequência, mas, se mudar, basta usar keys *onebox*url* ou até mesmo keys *url* para procurar a chave em cache que deseja excluir…
Posso confirmar que excluí com sucesso oneboxes em cache e recriei o HTML para posts afetados por dados quebrados em cache usando esse método.