Implement remote follow

src/processor/http/follow.ts

@@ -0,0 +1,89 @@
+import { request } from 'https';
+import { sign } from 'http-signature';
+import { URL } from 'url';
+import User, { ILocalAccount, IRemoteAccount, pack as packUser } from '../../models/user';
+import Following from '../../models/following';
+import event from '../../common/event';
+import notify from '../../common/notify';
+import context from '../../common/remote/activitypub/renderer/context';
+import render from '../../common/remote/activitypub/renderer/follow';
+import config from '../../conf';
+
+export default ({ data }, done) => Following.findOne({ _id: data.following }).then(({ followerId, followeeId }) => {
+	const promisedFollower = User.findOne({ _id: followerId });
+	const promisedFollowee = User.findOne({ _id: followeeId });
+
+	return Promise.all([
+		// Increment following count
+		User.update(followerId, {
+			$inc: {
+				followingCount: 1
+			}
+		}),
+
+		// Increment followers count
+		User.update({ _id: followeeId }, {
+			$inc: {
+				followersCount: 1
+			}
+		}),
+
+		// Notify
+		promisedFollowee.then(followee => followee.host === null ?
+			notify(followeeId, followerId, 'follow') : null),
+
+		// Publish follow event
+		Promise.all([promisedFollower, promisedFollowee]).then(([follower, followee]) => {
+			const followerEvent = packUser(followee, follower)
+				.then(packed => event(follower._id, 'follow', packed));
+			let followeeEvent;
+
+			if (followee.host === null) {
+				followeeEvent = packUser(follower, followee)
+					.then(packed => event(followee._id, 'followed', packed));
+			} else {
+				followeeEvent = new Promise((resolve, reject) => {
+					const {
+						protocol,
+						hostname,
+						port,
+						pathname,
+						search
+					} = new URL(followee.account as IRemoteAccount).inbox);
+
+					const req = request({
+						protocol,
+						hostname,
+						port,
+						method: 'POST',
+						path: pathname + search,
+					}, res => {
+						res.on('close', () => {
+							if (res.statusCode >= 200 && res.statusCode < 300) {
+								resolve();
+							} else {
+								reject(res);
+							}
+						});
+
+						res.on('data', () => {});
+						res.on('error', reject);
+					});
+
+					sign(req, {
+						authorizationHeaderName: 'Signature',
+						key: (follower.account as ILocalAccount).keypair,
+						keyId: `acct:${follower.username}@${config.host}`
+					});
+
+					const rendered = render(follower, followee);
+					rendered['@context'] = context;
+
+					req.end(JSON.stringify(rendered));
+				});
+			}
+
+			return Promise.all([followerEvent, followeeEvent]);
+		})
+	]);
+}).then(done, done);

src/processor/http/index.ts

@@ -1,7 +1,9 @@
+import follow from './follow';
 import performActivityPub from './perform-activitypub';
 import reportGitHubFailure from './report-github-failure';
 
 const handlers = {
+  follow,
   performActivityPub,
   reportGitHubFailure,
 };