feat: Create(Note) on new topic or reply

This is a naive WIP implementation that federates everything out publicly. It does not take category privileges into account!

src/api/activitypub.js

@@ -13,6 +13,7 @@ const nconf = require('nconf');
 const db = require('../database');
 const activitypub = require('../activitypub');
 const user = require('../user');
+const posts = require('../posts');
 
 const activitypubApi = module.exports;
 
@@ -49,3 +50,57 @@ activitypubApi.unfollow = async (caller, { uid: actorId }) => {
 		db.decrObjectField(`user:${caller.uid}`, 'followingRemoteCount'),
 	]);
 };
+
+activitypubApi.create = {};
+
+activitypubApi.create.post = async (caller, { post }) => {
+	const id = `${nconf.get('url')}/post/${post.pid}`;
+	const published = new Date(post.timestamp).toISOString();
+	const [userslug, raw, followers] = await Promise.all([
+		user.getUserField(caller.uid, 'userslug'),
+		posts.getPostField(post.pid, 'content'),
+		db.getSortedSetMembers(`followersRemote:${caller.uid}`),
+	]);
+
+	// todo: post visibility, category privileges integration
+	const recipients = {
+		to: [activitypub._constants.publicAddress],
+		cc: [`${nconf.get('url')}/user/${userslug}/followers`],
+	};
+	const targets = new Set(followers);
+
+	let inReplyTo = null;
+	if (post.toPid) {
+		inReplyTo = activitypub.helpers.isUri(post.toPid) ? post.toPid : id;
+		const parentId = await posts.getPostField(post.toPid, 'uid');
+		if (activitypub.helpers.isUri(parentId)) {
+			recipients.to.unshift(parentId);
+			targets.add(parentId);
+		}
+	}
+
+	const object = {
+		id,
+		type: 'Note',
+		...recipients,
+		inReplyTo,
+		published,
+		url: id,
+		attributedTo: `${nconf.get('url')}/user/${post.user.userslug}`,
+		sensitive: false, // todo
+		content: post.content,
+		source: {
+			content: raw,
+			mediaType: 'text/markdown',
+		},
+		// replies: {}  todo...
+	};
+
+	const payload = {
+		type: 'Create',
+		...recipients,
+		object,
+	};
+
+	await activitypub.send(caller.uid, Array.from(targets), payload);
+};