317

Quick video demonstrating that lemmy.world sends every activity out twice (i.imgur.com)

submitted 7 months ago by freamon@lemmy.world to c/fediverse@lemmy.world

34 comments fedilink hide all child comments

I realise this is a known issue and that lemmy.world isn't the only instance that does this. Also, I'm aware that there are other things affecting federation. But I'm seeing some things not federate, and can't help thinking that things would be going smoother if all the output from the biggest lemmy instance wasn't 50% spam.

Hopefully this doesn't seem like I'm shit-stirring, or trying to make the Issue I'm interested in more important than other Issues. It's something I mention occasionally, but it might be a bit abstract if you're not the admin of another instance.

The red terminal is a tail -f of the nginx log on my server. The green terminal is outputting some details from the ActivityPub JSON containing the Announce. You should be able to see the correlation between the lines in the nginx log, and lines from the activity, and that everything is duplicated.

This was generated by me commenting on an old post, using content that spawns an answer from a couple of bots, and then me upvoting the response. (so CREATE, CREATE, LIKE, is being announced as CREATE, CREATE, CREATE, CREATE, LIKE, LIKE). If you scale that up to every activity by every user, you'll appreciate that LW is creating a lot of work for anyone else in the Fediverse, just to filter out the duplicates.

you are viewing a single comment's thread
view the rest of the comments

[-] hoshikarakitaridia@lemmy.world 12 points 7 months ago

If the first one is OPTION, would that be a bug? Would the right design principle be to do it once per endpoint and then cache it for future requests?

I'm really curious cause I don't know how this usually works....

[-] scrubbles@poptalk.scrubbles.tech 7 points 7 months ago

That's pretty standard with most libraries

[-] Lemzlez@lemmy.world 3 points 7 months ago

I’ve never really seen this in (Java/Rust/PHP) backend personally, only in client-side JS (the CORS preflight).

It’s a security feature for browsers doing calls (checking the CORS headers before actually calling the endpoint), but for backends the only place it makes sense is if you’re implementing something like webhooks, to validate the (user submitted) endpoint.

[-] ericjmorey@discuss.online 1 points 7 months ago

I wonder if the legacy webhooks implementation in Lemmy has left some artifacts that show up when the services that comprise Lemmy are split up as they are for larger instances.

This is pure speculation.