Michael Puckett michaelcpuckett

I've commented a few times about some issues I see with the scalability of ActivityPub - the protocol behind the Fediverse and its best-known implementation Mastodon. A couple of folks have asked for more elaboration, so ... here it is.

First, let me add some disclaimers and warnings. I haven't devoted a lot of time to looking at ActivityPub, so there might be some things I've misunderstood about it. On the other hand, I've brought bigger systems - similar node counts and orders of magnitude more activity per node - from broken to working well based on less study of the protocols involved. So if you want to correct particular misconceptions, that's great. Thank you in advance. If you want to turn this into an appeal to authority and say that I'm wrong only because I haven't developed a full ActivityPub implementation or worked on it for X years ... GTFO.

What

What is ActivityPub? It's an HTTP- and JSON-based protocol for exchanging information about "activities". An activity could be many things.

React lifecycle cheatsheet

Method	Side effects¹	State updates²	Example uses
Mounting
`componentWillMount`		✓	Constructor equivalent for `createClass`
`render`			Create and return element(s)
`componentDidMount`	✓	✓	DOM manipulations, network requests, etc.
Updating
`componentWillReceiveProps`		✓	Update `state` based on changed `props`

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

	"workbench.editor.customLabels.patterns": {
	"/routes//+page.svelte": "${dirname(1)}/${dirname}",
	"/routes//+page.server.ts": "/${dirname} [server]",
	"/app//page.tsx": "${dirname}.${extname}",
	"/app//layout.tsx": "${dirname}/layout.${extname}"
	}

	{
	"emojis": [
	{"emoji": "👩‍👩‍👧‍👧", "name": "family: woman, woman, girl, girl", "shortname": ":woman_woman_girl_girl:", "unicode": "1F469 200D 1F469 200D 1F467 200D 1F467", "html": "👩&zwj;👩&zwj;👧&zwj;👧", "category": "People & Body (family)", "order": ""},
	{"emoji": "👩‍👩‍👧‍👦", "name": "family: woman, woman, girl, boy", "shortname": ":woman_woman_girl_boy:", "unicode": "1F469 200D 1F469 200D 1F467 200D 1F466", "html": "👩&zwj;👩&zwj;👧&zwj;👦", "category": "People & Body (family)", "order": ""},
	{"emoji": "👩‍👩‍👦‍👦", "name": "family: woman, woman, boy, boy", "shortname": ":woman_woman_boy_boy:", "unicode": "1F469 200D 1F469 200D 1F466 200D 1F466", "html": "👩&zwj;👩&zwj;👦&zwj;👦", "category": "People & Body (family)", "order": ""},
	{"emoji": "👨‍👩‍👧‍👧", "name": "family: man, woman, girl, girl", "shortname": ":man_woman_girl_girl:", "unicode": "1F468 200D 1F469 200D 1F467 200D 1F467", "html": "👨&zwj;👩&z

	/**
	* Updates the passed dialog to retain focus and restore it when the dialog is closed. Won't
	* upgrade a dialog more than once. Supports IE11+ and is a no-op otherwise.
	* @param {!HTMLDialogElement} dialog to upgrade
	*/
	var registerFocusRestoreDialog = (function() {
	if (!window.WeakMap \|\| !window.MutationObserver) {
	return function() {};
	}
	var registered = new WeakMap();

	import { EditorState, SelectionState } from 'draft-js';

	import getSelectedBlocks from './getSelectedBlocks';

	/**
	* Calls a provided `modifier` function with a selection for each
	* selected block in the current editor selection. Passes through additional
	* arguments to the modifier.
	*
	* Note: At the moment it will retain the original selection and override

	#define _GNU_SOURCE 1
	#include <sched.h> // sched_setaffinity
	#include <stdint.h>
	#include <stdio.h>
	#include <limits.h>
	#include <stdlib.h>
	#include <stdint.h>
	#include <pthread.h>
	#include <assert.h>
	#include <sys/time.h>

	module.exports = (string) => {
	return string.replace(/([a-z0-9]\|(?=[A-Z]))([A-Z])/g, '$1-$2').toLowerCase();
	};