The Fediverse

It's any piece of software that implements the ActivityPub protocol.

Software that makes up the Fediverse

Mastodon (https://mastodon.social/)

Micro blogging software built around 500 character text posts.

Mastodon alternatives

Misskey (https://misskey.io/)

Pleroma (https://pleroma.social/)

Write Freely (https://writefreely.org/)

Plume (https://joinplu.me/)

What else?

Peertube (https://joinpeertube.org)

Funkwhale (https://funkwhale.audio/)

There's more!

PixelFed (https://pixelfed.org/)

Friendica (https://friendi.ca/)

Nextcloud (https://nextcloud.com/)

An ActivityPub Actor

An ActivityPub Actor

{"@context": "https://www.w3.org/ns/activitystreams",
 "type": "Person",
 "id": "https://social.example/alyssa/",
 "name": "Alyssa P. Hacker",
 "preferredUsername": "alyssa",
 "summary": "Lisp enthusiast hailing from MIT",
 "inbox": "https://social.example/alyssa/inbox/",
 "outbox": "https://social.example/alyssa/outbox/",
 "followers": "https://social.example/alyssa/followers/",
 "following": "https://social.example/alyssa/following/",
 "liked": "https://social.example/alyssa/liked/"}
			

Post a message

{"@context": "https://www.w3.org/ns/activitystreams",
 "type": "Note",
 "to": ["https://chatty.example/ben/"],
 "attributedTo": "https://social.example/alyssa/",
 "content": "Say, did you finish reading that book I lent you?"}
		

Wrap in a create object

{"@context": "https://www.w3.org/ns/activitystreams",
 "type": "Create",
 "id": "https://social.example/alyssa/posts/a29a6843-9feb-4c74-a7f7-081b9c9201d3",
 "to": ["https://chatty.example/ben/"],
 "actor": "https://social.example/alyssa/",
 "object": {"type": "Note",
            "id": "https://social.example/alyssa/posts/49e2d03d-b53a-4c4c-a95c-94a6abf45a19",
            "attributedTo": "https://social.example/alyssa/",
            "to": ["https://chatty.example/ben/"],
            "content": "Say, did you finish reading that book I lent you?"}}
		

Get a response

{"@context": "https://www.w3.org/ns/activitystreams",
 "type": "Create",
 "id": "https://chatty.example/ben/p/51086",
 "to": ["https://social.example/alyssa/"],
 "actor": "https://chatty.example/ben/",
 "object": {"type": "Note",
            "id": "https://chatty.example/ben/p/51085",
            "attributedTo": "https://chatty.example/ben/",
            "to": ["https://social.example/alyssa/"],
            "inReplyTo": "https://social.example/alyssa/posts/49e2d03d-b53a-4c4c-a95c-94a6abf45a19",
            "content": "
Argh, yeah, sorry, I'll get it back to you tomorrow.
                        
I was reviewing the section on register machines,
                           since it's been a while since I wrote one.
"}}
		

Alyssa hits 'like'

{"@context": "https://www.w3.org/ns/activitystreams",
 "type": "Like",
 "id": "https://social.example/alyssa/posts/5312e10e-5110-42e5-a09b-934882b3ecec",
 "to": ["https://chatty.example/ben/"],
 "actor": "https://social.example/alyssa/",
 "object": "https://chatty.example/ben/p/51086"}
		

New public post

{"@context": "https://www.w3.org/ns/activitystreams",
 "type": "Create",
 "id": "https://social.example/alyssa/posts/9282e9cc-14d0-42b3-a758-d6aeca6c876b",
 "to": ["https://social.example/alyssa/followers/",
        "https://www.w3.org/ns/activitystreams#Public"],
 "actor": "https://social.example/alyssa/",
 "object": {"type": "Note",
            "id": "https://social.example/alyssa/posts/d18c55d4-8a63-4181-9745-4e6cf7938fa1",
            "attributedTo": "https://social.example/alyssa/",
            "to": ["https://social.example/alyssa/followers/",
                   "https://www.w3.org/ns/activitystreams#Public"],
            "content": "Lending books to friends is nice.  Getting them back is even nicer! :)"}}
		

What is Mastodon?

Mastodon Moderation Principles

• Community
• Ratios
• Approachable

Mastodon Design Decisions

Making the fediverse better a decision at a time

• Deliberately does not support arbitary search
• Delete and re-draft

Mastodon Design Decisions

Making the fediverse better a decision at a time

• No quoting of messages
• Privacy

Mastodon vs Twitter

• No ads
• No tracking
• 500 character support
• Polls
• Content warning

Default interface

Example: Peertube and Mastodon

Example: Peertube and Mastodon [comment]

Example: Peertube and Mastodon [comment]

Example: Peertube and Mastodon [comment]

Example: Peertube and Mastodon [subscribe]

Example: Peertube and Mastodon [subscribe]

Example: Peertube and Mastodon [subscribe]

Implementing a basic ActivityPub server

Goal: Send a Mastodon user a message from our own, non-Mastodon server

1. Create a verifiable actor
2. Format the message with ActivityPub
3. Cryptographically sign the message then POST

Generate RSA keypair

openssl genrsa -out private.pem 2048
openssl rsa -in private.pem -outform PEM -pubout -out public.pem

Create an actor

{
	"@context": [
		"https://www.w3.org/ns/activitystreams",
		"https://w3id.org/security/v1"
	],

	"id": "https://my-example.com/actor",
	"type": "Person",
	"preferredUsername": "alice",
	"inbox": "https://my-example.com/inbox",

	"publicKey": {
		"id": "https://my-example.com/actor#main-key",
		"owner": "https://my-example.com/actor",
		"publicKeyPem": "-----BEGIN PUBLIC KEY-----...-----END PUBLIC KEY-----"
	}
}

Discoverable via Webfinger

endpoint: /.well-known/webfinger
queries: /.well-known/webfinger?resource=acct:bob@my-example.com

{
	"subject": "acct:alice@my-example.com",

	"links": [
		{
			"rel": "self",
			"type": "application/activity+json",
			"href": "https://my-example.com/actor"
		}
	]
}

Construct our message

{
	"@context": "https://www.w3.org/ns/activitystreams",

	"id": "https://my-example.com/create-hello-world",
	"type": "Create",
	"actor": "https://my-example.com/actor",

	"object": {
		"id": "https://my-example.com/hello-world",
		"type": "Note",
		"published": "2018-06-23T17:17:11Z",
		"attributedTo": "https://my-example.com/actor",
		"inReplyTo": "https://mastodon.social/@Gargron/100254678717223630",
		"content": "
Hello world
",
		"to": "https://www.w3.org/ns/activitystreams#Public"
	}
}

Create HTTP signature and POST

require 'http'
require 'openssl'

document      = File.read('create-hello-world.json')
date          = Time.now.utc.httpdate
keypair       = OpenSSL::PKey::RSA.new(File.read('private.pem'))
signed_string = "(request-target): post /inbox\nhost: mastodon.social\ndate: #{date}"
signature     = Base64.strict_encode64(keypair.sign(OpenSSL::Digest::SHA256.new, signed_string))
header        = 'keyId="https://my-example.com/actor",headers="(request-target) host date",signature="' + signature + '"'

HTTP.headers({ 'Host': 'mastodon.social', 'Date': date, 'Signature': header })
    .post('https://mastodon.social/inbox', body: document)

Done!

Mastodon-cat

$input = file_get_contents("php://stdin");
require 'test_credentials.php';

$name = 'Adelaide'; $instance = 'glasgow.social';
$oAuth = new Colorfield\Mastodon\MastodonOAuth($name, $instance);
$oAuth->config->setClientId($client_id);
$oAuth->config->setClientSecret($client_secret);
$oAuth->config->setBearer($bearer);
$mastodonAPI = new Colorfield\Mastodon\MastodonAPI($oAuth->config);

$params['status'] = $input;
$params['visibility'] = "unlisted";
$post = $mastodonAPI->post('/statuses', $params);
	

Mastodon/Reddit PHP Bot

/* SNIP (Get Reddit RSS feed and save as $summary) */

$params['status'] = $summary;
$params['visibility'] = "public";
require 'bot_credentials.php';

$name = 'RedditBot'; $instance = 'glasgow.social';

$oAuth = new Colorfield\Mastodon\MastodonOAuth($name, $instance);
$oAuth->config->setClientId($client_id);
$oAuth->config->setClientSecret($client_secret);
$oAuth->config->setBearer($bearer);
$mastodonAPI = new Colorfield\Mastodon\MastodonAPI($oAuth->config);

$post = $mastodonAPI->post('/statuses', $params);