Can you guess when was a link to one of my projects shared here on fedi yesterday?

Seriously, we're getting close to having a true "Fediverse effect" (c.f. ). :blobaww:


@rysiek Yeah, but you have to consider the traffic from servers fetching the preview. (Sorry)

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@Gargron oh, that's exactly what I meant. I should have made it clear. 👍

@rysiek @Gargron Yeah, there's actually a bit of an issue there for those of us trying to tread lightly on the planet.

Not sure how to fix it (in a decentralised way) but so many requests is a form of DDoS for smaller sites.

@dajbelshaw @rysiek There already seems to be a delay before fetching previews, dunno whether it is an explicit one or just the result of the action landing in the back of my sidekiq queue and needing some time to be at the front.
But spreading preview fetches over a short time frame helps cutting the spikes. @Gargron

@dajbelshaw @Gargron I suppose some form of "link posted on Instance X, Instance X makes the request and caches the result, and then attaches it to the toot as it federates; other servers can decide to either use that, or make their own requests" could work?

@rysiek @Gargron You'd have to really trust Instance X, which would lead to pseudo-centralisation. But some form of cascade would be good.

@dajbelshaw @Gargron well you already trust Instance X, nothing is stopping it from modifying the URL, or the toot, or metadata, or whatever.

So, adding cached link previews doesn't seem like a substantial trust issue.

@rysiek @Gargron I'm all up for experiments in this area, because as the Fediverse grows, the problem will only magnify

@Gargron that said, at some point a conversation might need to happen on how to stop fedi from accidentally becoming a distributed denial of service tool.

400 requests in a few short minutes is something that *could* already cause some issues for some poorly configured sites. And fedi is growing.

It is not out of the realm of possibility that in a year or two it grows to a level where posting a link can bring most WordPress sites down for a few minutes.

With deniability ("I was only sharing).

@rysiek It's not rare to see "temporary overload" type messages from web sites that have been linked from the Fediverse. Usually takes 10 to 15 minutes until the worst of the storm is over.

Personally, I'd really like to be able to disable link preview fetching on my instance - they also take up a sizable chunk of storage on my side.

Otherweise, maybe distribute link previews as actual media from the originating instance and have others fetch just the page title for verification?


@rysiek (Ok, the latter looks like a dumb idea in retrospect, since I don't actually know of a way to get at title or meta tags without requesting the full page.)


@rysiek @Gargron For anyone interested in this there is a giant thread on the github issue.

@rysiek @Gargron I guess it's safe as long as we're talking about a few hundreds in few minutes, not seconds. And even then disruption will be only temporary. But if it is really a problem, maybe it's worth to report an issue? Fediverse probably could somehow fetch preview once and share it internally.

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