cfcosta
Cainã Costa

https://cfcosta.com

Time's Person of the Year, 2006. Software engineer, Rust and Distributed Systems.

Public Key

npub1e73alysrc3q2tw2tr7rrp98xsdqje6w5y2nln8zngmjrlcsqrkfqtyxxjg

NIP-05 Address

cfcosta@cfcosta.com

NIP-57 Address

cfcosta@getalby.com

Profile Code

nprofile1qqsvlg7ljgpugs99h993lp3sjnngxsfva82z9flen3f5deplugqpmysdjcvvt

Author Public Key

npub1e73alysrc3q2tw2tr7rrp98xsdqje6w5y2nln8zngmjrlcsqrkfqtyxxjg

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Last Notes

2024-09-01 14:06:21

Anyone that knows redb can try to run this and explain why it happens?
https://github.com/cfcosta/redb-bug/blob/main/src/main.rs
Basically I inject errors on storage operations, but the database gets inconsistent/borked when it happens.
Of course, I'm pushing it to an extreme level, but I kinda need that level of trust.

2024-08-30 23:45:01

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Cardanistas sempre bem vindos (por mim pelo menos)

2024-08-30 22:40:33

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Será que se o PCC começar a usar o X pra trabalho eles liberam?

2024-08-30 22:32:20

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Dentro da cadeia internet é livre

2024-08-30 21:33:52

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Some, yeah

2024-08-30 21:32:56

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Worst part is not even the network itself, couldn’t care less and much prefer nostr.
It’s the people that are there and that now will be out of our reach. I’m not going to fucking instagram

2024-08-30 21:23:54

But in the end, here's the deal.
I created mugraph precisely because I saw the censorship coming. Privacy is a human right, and I'll do my part so it stays that way.

2024-08-30 21:19:12

Feels good to actually see more brazilians here.
Hopefully this is the kickstart we need, considering both bluesky and the fediverse are left eco-chambers.

2024-04-29 21:02:05

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I've specified something like this before, worked almost full time just thinking about this problem for 3 months or so. In a short answer: Double Ratchet/X3DH for messaging, zero-knowledge proofs so the server doesn't know the sender or the receiver.
Keep the merkle root of a Merkle Search Tree, derive the next key based on the root of the current chat tree. Tree is self-balancing and automatically ordered to keep causality in check.
Inside each message, keep an encrypted Hybrid Logical Clock id on each message, to keep both causal and wall clock synchrony, even in case of clock drifts.
For each destination (like a group), publish a single entry, and multiple public keys, one for each destination. Add a random number of other public keys to obfuscate which are real and which are not.
When fetching, user sends a proof that, given the sender public key, they have ownership of the proof. Proof is consumed on the relay. User updates their own Merkle Search Tree on the client with each proof they consumed.
User then publishes new proofs for the same content they received, but with their own "backup key". These are kept in the relay for user device backup.
All keys are ephemeral, except the backup key, which can be the user nsec key. User publishes public one-time-use keys (either by publishing to relays or NIP-05).
Basically the chat conversation is a CRDT, and the same relay mechanism that nostr uses guarantees delivery without the need for consistency (which are also not required for crdts).
A little bit stream of counciousness, but I can give detailed explanations about everything I talked about here, and even wrote most of it down, just ping me if you need.

2024-04-28 14:39:38

Covenants? DLCs? Stablecoins? What are you daydreaming about? Take your creatine, it's leg day.https://m.primal.net/IAvB.png

2023-03-18 20:29:57

Hot take: WASM is a better Docker, not a better jvm. Being better than the JVM is just a nice side-effect.

2023-03-18 20:28:29

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I really like the one time payment model, but if I had to choose a recurring one, would prefer to pay yearly. Recurring transactions in crypto are shit right now.

2023-03-18 20:27:10

https://i.imgur.com/FxcO7NG.jpg

2023-03-16 14:22:22

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Is there a NIP already covering client auth?

2023-03-13 17:01:48

https://i.imgur.com/k4QRjcE.jpg

2023-03-13 01:08:21

https://i.imgur.com/NIbOorH.jpg

2023-03-12 22:32:57

So, after two years from this @GmanLives video, I finally gave a chance to play @ProdeusGame. It is really, really, really good. It really feels like Doom 2016 went full Brutal Doom 2 instead of drinking from the Quake 3 fountain until it drowns.
https://youtu.be/UUGXuAUlM28

2023-03-11 13:41:36

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It will change if it is successful, but that's fine, the same protocol supports small gated communities and the open web, which is great.

2023-03-09 12:55:39

Good morning nostr peoples!

2023-03-08 22:01:07

A fairly competent note-taking system for people that use the terminal heavily in 18 lines of Nix (3 of shell script, really, the rest is just install stuff):
https://gist.github.com/cfcosta/2831e83aadd068bcd6ea4999fe50b72c

2023-03-08 21:35:15

How I take my notes:
Create three scripts: today, tomorrow and yesterday.
Each of them opens the editor with the correct file name, like 2023-03-08.md. Add notes there. There you go.

2023-03-08 17:23:10

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Oh yeah, but you can delay the loading if you are not showing anything to the user, and do some smart prefetching as the user navigates

2023-03-08 17:22:04

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Usually the answer is not loading them at all, or if you do, not building objects for everything. Usually splitting from array of structs into struct of arrays also helps, as you can vectorize better (not sure if NEON is available for cellphones though) and have better cache locality.

2023-03-08 17:20:17

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Usually the answer is not loading them at all, or if you do, not building objects for everything. Usually splitting into arrays of structs instead of structs of arrays also helps, as you can vectorize better (not sure if NEON is available for cellphones though)

2023-03-07 22:27:45

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After skimming 100k posts (long story) on the most popular servers, yes, this and csam/glorification of csam.

2023-03-07 21:35:32

https://void.cat/d/9Eic1iLuhBbVAVubqBDtv6.webp

2023-03-07 12:44:24

Software has to be correct before useful, useful before fast, and fast before beautiful. Anything else and you are inverting the priorities and will suffer for it later.

2023-03-07 10:32:05

https://i.imgur.com/RWgY0Qs.jpg

2023-03-03 19:40:54

https://i.imgur.com/hihOLkw.jpg

2023-03-03 13:34:22

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Trust the science, kill your cat.
#[0]

2023-03-01 17:22:19

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It's a joke...

2023-03-01 16:37:31

https://i.imgur.com/u7EdeYe.jpg

2023-03-01 16:15:39

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Sup!

2023-03-01 02:35:57

I got paid 1 cent to receive notifications for one hour. If that's the kind of spam we have here, at least I'm being paid.

2023-03-01 01:28:03

#[0] silence

2023-03-01 01:09:34

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He's memeing the spam on the bird site, I think

2023-03-01 00:45:38

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That's my favorite part of the elephant network, and it's even better over here.

2023-03-01 00:43:58

https://i.imgur.com/dMNrymK.jpg

2023-03-01 00:43:04

Friends, are there any mirrored accounts from the other networks here that you follow? I know of #[0] , #[1] , #[2]. Any others?

2023-02-28 21:19:24

https://i.imgur.com/q3fY8HR.jpg

2023-02-28 17:25:10

We do exactly this on my team at work, and it’s working great. Learning curve is still kinda bad, but damn if the results aren’t worth it.
https://floxdev.com/blog/flox-and-containers

2023-02-28 17:00:20

Someone managed to launch a pretty good ActivityPub mirror here on Nostr before I could finish mine :( They even have a cool name (Mostr), but I still think my name is better (nostodon).
I'm still going to finish it, as it's almost there, but the code is now open-source for everyone that wants to contribute (or would like to see something, but do not want to write Typescript).
In case anyone wanna check it out, it's available here: https://github.com/cfcosta/nostodon
It has been running for more than a week, listening to events and posting on a local relay, and I'm pretty sure it should be able to handle ALL of the ActivityPub in a few servers and a good strfry relay in the backend.
If you still want to see this going live, just ping me and we can make it happen, as long as there's a reason (competition is a good reason, but there isn't much space for two solutions doing the same thing at the moment).

2023-02-28 16:28:44

https://i.imgur.com/C9cTmfK.jpg

2023-02-28 16:26:58

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Bem pouquinho de alemão também :P

2023-02-28 15:16:50

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Разве это не молния? Я не вижу, чтобы это шло быстрее.

2023-02-28 14:57:30

Just to prove me wrong, someone zapped me 17 sats hehehe
Point still stands though.

2023-02-28 14:54:34

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I doubt #[3] thought about the game theory of it, but it's shaping really nicely.

2023-02-28 14:53:14

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Thanks, didn't know about that one!

2023-02-28 14:52:20

Zaps can do something that I thought wasn't possible before: it's more lucrative to actually generate good content than it is to scam people with stuff.
The smallest zap I've seen so far is 500 sats ($0.12). That's more than the CPM of many platforms. Posts from people like #[0] get much, much more than 1 zap per tweet.
It's easier to spam here than it is on other networks, but as more people move to paid relays, it becomes much much more expensive to do. Or, you can just write something cool and watch the money flows to your account. Which one seems cheaper?

2023-02-28 14:37:39

I've seen lots of people with a reachability problem here.
There's a simple way to fix it: listen to only the relays you do care about, but publish to as many active relays as possible.
People that don't share your relays are not going to have access to your posts, but posting is "free".
https://nostr-wine.github.io/filter-relay is a great "one-relay" solution if you are using nostr.wine already.

2023-02-28 14:31:54

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Here it shows you only posted on nostr.wine, maybe you need to add a fan out like wss://filter.nostr.wine/yourpubkey?broadcast=true

2023-02-28 14:25:46

https://i.imgur.com/IFvcDXp.jpg

2023-02-28 14:17:01

Just got access to the new Bing. Surprisingly, the biggest advancement over ChatGPT is not the model or internet access, but the fact that it has a mobile app.

2023-02-28 10:14:50

Morning, famiglia nostra

2023-02-28 01:55:43

Nostr is an incredible social network, it's much harder to find stuff to post than it is to develop stuff for it.

2023-02-28 01:05:27

I really like that #[0] is mirrored here.
I do like the whole "nostr and nostr accessories" thing that small projects have, but it feels much more complete when people are actually talking about other stuff.

2023-02-27 23:05:05

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Nice to hear that, just bought some with Fiat and used a separated wallet. Next time will look at the other options.

2023-02-27 22:59:24

Ok, zapping is pretty cool. I think the biggest barrier to entry is to actually move BTC to LN. It's really surprising how dificult it is.

2023-02-27 22:42:31

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Thank you! <3

2023-02-27 22:40:17

So yeah, finally have bitten the bullet, and am on nostr.wine and eden.nostr.land :D Global feed looks so much better already.
And hi guys!

2023-02-27 21:36:34

Verifying my Nostr Nests identity: XTph2inYQsvQ31WaU3P-vEkTatpKHKHbGD57K0vllRo
https://nostrnests.com

2023-02-27 21:30:57

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FYI, I was doing exactly that here: https://github.com/cfcosta/nostodon
Wanna join efforts?

2023-02-27 21:30:31

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I actually wrote exactly that for the past three weeks or so. It is working, pending some small fixes and it will be live this weekend. We have been able to process 1.2mi events/week, more if we plugged directly.
Will launch on https://nostodon.org pretty soon, but the code is live here: https://github.com/cfcosta/nostodon

2023-02-27 14:21:34

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Ack

2023-02-27 13:36:48

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The only real downside is: you still need a nixos base image on your cloud to make it work, and no clouds provide that out of the box. Installing it should be fairly easy though, same to clone and set-up other applications.
If I have to deploy something else on another machine, I can just clone it and apply the new configuration directly.

2023-02-27 13:34:12

Simplest deploy stack ever: nixos + nix-copy-closure and running an activation script. 30 or so lines of code to setup, less if you use morph[1] or something like that, and there you go. Everything just works, systemd takes care of starting and restarting, rollbacks are fairly easy to do, takes less than 30 seconds after build to run.
[1]: https://github.com/DBCDK/morph

2023-02-27 13:32:12

Hello my Nostr friends :D

2023-02-04 22:33:33

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Moved from what to what? PostgreSQL to something else?