Implement remote status retrieval

12 files changed, 857 insertions, 0 deletions

diff --git a/src/common/drive/add-file.ts b/src/common/drive/add-file.ts
new file mode 100644
index 0000000000..52a7713dd9
--- /dev/null
+++ b/src/common/drive/add-file.ts
@@ -0,0 +1,307 @@
+import { Buffer } from 'buffer';
+import * as fs from 'fs';
+import * as tmp from 'tmp';
+import * as stream from 'stream';
+
+import * as mongodb from 'mongodb';
+import * as crypto from 'crypto';
+import * as _gm from 'gm';
+import * as debug from 'debug';
+import fileType = require('file-type');
+import prominence = require('prominence');
+
+import DriveFile, { getGridFSBucket } from '../../models/drive-file';
+import DriveFolder from '../../models/drive-folder';
+import { pack } from '../../models/drive-file';
+import event, { publishDriveStream } from '../event';
+import getAcct from '../user/get-acct';
+import config from '../../conf';
+
+const gm = _gm.subClass({
+	imageMagick: true
+});
+
+const log = debug('misskey:drive:add-file');
+
+const tmpFile = (): Promise<string> => new Promise((resolve, reject) => {
+	tmp.file((e, path) => {
+		if (e) return reject(e);
+		resolve(path);
+	});
+});
+
+const addToGridFS = (name: string, readable: stream.Readable, type: string, metadata: any): Promise<any> =>
+	getGridFSBucket()
+		.then(bucket => new Promise((resolve, reject) => {
+			const writeStream = bucket.openUploadStream(name, { contentType: type, metadata });
+			writeStream.once('finish', (doc) => { resolve(doc); });
+			writeStream.on('error', reject);
+			readable.pipe(writeStream);
+		}));
+
+const addFile = async (
+	user: any,
+	path: string,
+	name: string = null,
+	comment: string = null,
+	folderId: mongodb.ObjectID = null,
+	force: boolean = false
+) => {
+	log(`registering ${name} (user: ${getAcct(user)}, path: ${path})`);
+
+	// Calculate hash, get content type and get file size
+	const [hash, [mime, ext], size] = await Promise.all([
+		// hash
+		((): Promise<string> => new Promise((res, rej) => {
+			const readable = fs.createReadStream(path);
+			const hash = crypto.createHash('md5');
+			const chunks = [];
+			readable
+				.on('error', rej)
+				.pipe(hash)
+				.on('error', rej)
+				.on('data', (chunk) => chunks.push(chunk))
+				.on('end', () => {
+					const buffer = Buffer.concat(chunks);
+					res(buffer.toString('hex'));
+				});
+		}))(),
+		// mime
+		((): Promise<[string, string | null]> => new Promise((res, rej) => {
+			const readable = fs.createReadStream(path);
+			readable
+				.on('error', rej)
+				.once('data', (buffer: Buffer) => {
+					readable.destroy();
+					const type = fileType(buffer);
+					if (type) {
+						return res([type.mime, type.ext]);
+					} else {
+						// 種類が同定できなかったら application/octet-stream にする
+						return res(['application/octet-stream', null]);
+					}
+				});
+		}))(),
+		// size
+		((): Promise<number> => new Promise((res, rej) => {
+			fs.stat(path, (err, stats) => {
+				if (err) return rej(err);
+				res(stats.size);
+			});
+		}))()
+	]);
+
+	log(`hash: ${hash}, mime: ${mime}, ext: ${ext}, size: ${size}`);
+
+	// detect name
+	const detectedName: string = name || (ext ? `untitled.${ext}` : 'untitled');
+
+	if (!force) {
+		// Check if there is a file with the same hash
+		const much = await DriveFile.findOne({
+			md5: hash,
+			'metadata.userId': user._id
+		});
+
+		if (much !== null) {
+			log('file with same hash is found');
+			return much;
+		} else {
+			log('file with same hash is not found');
+		}
+	}
+
+	const [wh, averageColor, folder] = await Promise.all([
+		// Width and height (when image)
+		(async () => {
+			// 画像かどうか
+			if (!/^image\/.*$/.test(mime)) {
+				return null;
+			}
+
+			const imageType = mime.split('/')[1];
+
+			// 画像でもPNGかJPEGかGIFでないならスキップ
+			if (imageType != 'png' && imageType != 'jpeg' && imageType != 'gif') {
+				return null;
+			}
+
+			log('calculate image width and height...');
+
+			// Calculate width and height
+			const g = gm(fs.createReadStream(path), name);
+			const size = await prominence(g).size();
+
+			log(`image width and height is calculated: ${size.width}, ${size.height}`);
+
+			return [size.width, size.height];
+		})(),
+		// average color (when image)
+		(async () => {
+			// 画像かどうか
+			if (!/^image\/.*$/.test(mime)) {
+				return null;
+			}
+
+			const imageType = mime.split('/')[1];
+
+			// 画像でもPNGかJPEGでないならスキップ
+			if (imageType != 'png' && imageType != 'jpeg') {
+				return null;
+			}
+
+			log('calculate average color...');
+
+			const buffer = await prominence(gm(fs.createReadStream(path), name)
+				.setFormat('ppm')
+				.resize(1, 1)) // 1pxのサイズに縮小して平均色を取得するというハック
+				.toBuffer();
+
+			const r = buffer.readUInt8(buffer.length - 3);
+			const g = buffer.readUInt8(buffer.length - 2);
+			const b = buffer.readUInt8(buffer.length - 1);
+
+			log(`average color is calculated: ${r}, ${g}, ${b}`);
+
+			return [r, g, b];
+		})(),
+		// folder
+		(async () => {
+			if (!folderId) {
+				return null;
+			}
+			const driveFolder = await DriveFolder.findOne({
+				_id: folderId,
+				userId: user._id
+			});
+			if (!driveFolder) {
+				throw 'folder-not-found';
+			}
+			return driveFolder;
+		})(),
+		// usage checker
+		(async () => {
+			// Calculate drive usage
+			const usage = await DriveFile
+				.aggregate([{
+					$match: { 'metadata.userId': user._id }
+				}, {
+					$project: {
+						length: true
+					}
+				}, {
+					$group: {
+						_id: null,
+						usage: { $sum: '$length' }
+					}
+				}])
+				.then((aggregates: any[]) => {
+					if (aggregates.length > 0) {
+						return aggregates[0].usage;
+					}
+					return 0;
+				});
+
+			log(`drive usage is ${usage}`);
+
+			// If usage limit exceeded
+			if (usage + size > user.driveCapacity) {
+				throw 'no-free-space';
+			}
+		})()
+	]);
+
+	const readable = fs.createReadStream(path);
+
+	const properties = {};
+
+	if (wh) {
+		properties['width'] = wh[0];
+		properties['height'] = wh[1];
+	}
+
+	if (averageColor) {
+		properties['avgColor'] = averageColor;
+	}
+
+	return addToGridFS(detectedName, readable, mime, {
+		userId: user._id,
+		folderId: folder !== null ? folder._id : null,
+		comment: comment,
+		properties: properties
+	});
+};
+
+/**
+ * Add file to drive
+ *
+ * @param user User who wish to add file
+ * @param file File path or readableStream
+ * @param comment Comment
+ * @param type File type
+ * @param folderId Folder ID
+ * @param force If set to true, forcibly upload the file even if there is a file with the same hash.
+ * @return Object that represents added file
+ */
+export default (user: any, file: string | stream.Readable, ...args) => new Promise<any>((resolve, reject) => {
+	// Get file path
+	new Promise((res: (v: [string, boolean]) => void, rej) => {
+		if (typeof file === 'string') {
+			res([file, false]);
+			return;
+		}
+		if (typeof file === 'object' && typeof file.read === 'function') {
+			tmpFile()
+				.then(path => {
+					const readable: stream.Readable = file;
+					const writable = fs.createWriteStream(path);
+					readable
+						.on('error', rej)
+						.on('end', () => {
+							res([path, true]);
+						})
+						.pipe(writable)
+						.on('error', rej);
+				})
+				.catch(rej);
+		}
+		rej(new Error('un-compatible file.'));
+	})
+	.then(([path, shouldCleanup]): Promise<any> => new Promise((res, rej) => {
+		addFile(user, path, ...args)
+			.then(file => {
+				res(file);
+				if (shouldCleanup) {
+					fs.unlink(path, (e) => {
+						if (e) log(e.stack);
+					});
+				}
+			})
+			.catch(rej);
+	}))
+	.then(file => {
+		log(`drive file has been created ${file._id}`);
+		resolve(file);
+
+		pack(file).then(serializedFile => {
+			// Publish drive_file_created event
+			event(user._id, 'drive_file_created', serializedFile);
+			publishDriveStream(user._id, 'file_created', serializedFile);
+
+			// Register to search database
+			if (config.elasticsearch.enable) {
+				const es = require('../../db/elasticsearch');
+				es.index({
+					index: 'misskey',
+					type: 'drive_file',
+					id: file._id.toString(),
+					body: {
+						name: file.name,
+						userId: user._id.toString()
+					}
+				});
+			}
+		});
+	})
+	.catch(reject);
+});
diff --git a/src/common/drive/upload_from_url.ts b/src/common/drive/upload_from_url.ts
new file mode 100644
index 0000000000..5dd9695936
--- /dev/null
+++ b/src/common/drive/upload_from_url.ts
@@ -0,0 +1,46 @@
+import * as URL from 'url';
+import { IDriveFile, validateFileName } from '../../models/drive-file';
+import create from './add-file';
+import * as debug from 'debug';
+import * as tmp from 'tmp';
+import * as fs from 'fs';
+import * as request from 'request';
+
+const log = debug('misskey:common:drive:upload_from_url');
+
+export default async (url, user, folderId = null): Promise<IDriveFile> => {
+	let name = URL.parse(url).pathname.split('/').pop();
+	if (!validateFileName(name)) {
+		name = null;
+	}
+
+	// Create temp file
+	const path = await new Promise((res: (string) => void, rej) => {
+		tmp.file((e, path) => {
+			if (e) return rej(e);
+			res(path);
+		});
+	});
+
+	// write content at URL to temp file
+	await new Promise((res, rej) => {
+		const writable = fs.createWriteStream(path);
+		request(url)
+			.on('error', rej)
+			.on('end', () => {
+				writable.close();
+				res(path);
+			})
+			.pipe(writable)
+			.on('error', rej);
+	});
+
+	const driveFile = await create(user, path, name, null, folderId);
+
+	// clean-up
+	fs.unlink(path, (e) => {
+		if (e) log(e.stack);
+	});
+
+	return driveFile;
+};
diff --git a/src/common/event.ts b/src/common/event.ts
new file mode 100644
index 0000000000..53520f11ce
--- /dev/null
+++ b/src/common/event.ts
@@ -0,0 +1,80 @@
+import * as mongo from 'mongodb';
+import * as redis from 'redis';
+import swPush from './push-sw';
+import config from '../conf';
+
+type ID = string | mongo.ObjectID;
+
+class MisskeyEvent {
+	private redisClient: redis.RedisClient;
+
+	constructor() {
+		// Connect to Redis
+		this.redisClient = redis.createClient(
+			config.redis.port, config.redis.host);
+	}
+
+	public publishUserStream(userId: ID, type: string, value?: any): void {
+		this.publish(`user-stream:${userId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	public publishSw(userId: ID, type: string, value?: any): void {
+		swPush(userId, type, value);
+	}
+
+	public publishDriveStream(userId: ID, type: string, value?: any): void {
+		this.publish(`drive-stream:${userId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	public publishPostStream(postId: ID, type: string, value?: any): void {
+		this.publish(`post-stream:${postId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	public publishMessagingStream(userId: ID, otherpartyId: ID, type: string, value?: any): void {
+		this.publish(`messaging-stream:${userId}-${otherpartyId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	public publishMessagingIndexStream(userId: ID, type: string, value?: any): void {
+		this.publish(`messaging-index-stream:${userId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	public publishOthelloStream(userId: ID, type: string, value?: any): void {
+		this.publish(`othello-stream:${userId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	public publishOthelloGameStream(gameId: ID, type: string, value?: any): void {
+		this.publish(`othello-game-stream:${gameId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	public publishChannelStream(channelId: ID, type: string, value?: any): void {
+		this.publish(`channel-stream:${channelId}`, type, typeof value === 'undefined' ? null : value);
+	}
+
+	private publish(channel: string, type: string, value?: any): void {
+		const message = value == null ?
+			{ type: type } :
+			{ type: type, body: value };
+
+		this.redisClient.publish(`misskey:${channel}`, JSON.stringify(message));
+	}
+}
+
+const ev = new MisskeyEvent();
+
+export default ev.publishUserStream.bind(ev);
+
+export const pushSw = ev.publishSw.bind(ev);
+
+export const publishDriveStream = ev.publishDriveStream.bind(ev);
+
+export const publishPostStream = ev.publishPostStream.bind(ev);
+
+export const publishMessagingStream = ev.publishMessagingStream.bind(ev);
+
+export const publishMessagingIndexStream = ev.publishMessagingIndexStream.bind(ev);
+
+export const publishOthelloStream = ev.publishOthelloStream.bind(ev);
+
+export const publishOthelloGameStream = ev.publishOthelloGameStream.bind(ev);
+
+export const publishChannelStream = ev.publishChannelStream.bind(ev);
diff --git a/src/common/push-sw.ts b/src/common/push-sw.ts
new file mode 100644
index 0000000000..44c328e833
--- /dev/null
+++ b/src/common/push-sw.ts
@@ -0,0 +1,52 @@
+const push = require('web-push');
+import * as mongo from 'mongodb';
+import Subscription from '../models/sw-subscription';
+import config from '../conf';
+
+if (config.sw) {
+	// アプリケーションの連絡先と、サーバーサイドの鍵ペアの情報を登録
+	push.setVapidDetails(
+		config.maintainer.url,
+		config.sw.public_key,
+		config.sw.private_key);
+}
+
+export default async function(userId: mongo.ObjectID | string, type, body?) {
+	if (!config.sw) return;
+
+	if (typeof userId === 'string') {
+		userId = new mongo.ObjectID(userId);
+	}
+
+	// Fetch
+	const subscriptions = await Subscription.find({
+		userId: userId
+	});
+
+	subscriptions.forEach(subscription => {
+		const pushSubscription = {
+			endpoint: subscription.endpoint,
+			keys: {
+				auth: subscription.auth,
+				p256dh: subscription.publickey
+			}
+		};
+
+		push.sendNotification(pushSubscription, JSON.stringify({
+			type, body
+		})).catch(err => {
+			//console.log(err.statusCode);
+			//console.log(err.headers);
+			//console.log(err.body);
+
+			if (err.statusCode == 410) {
+				Subscription.remove({
+					userId: userId,
+					endpoint: subscription.endpoint,
+					auth: subscription.auth,
+					publickey: subscription.publickey
+				});
+			}
+		});
+	});
+}
diff --git a/src/common/remote/activitypub/act/create.ts b/src/common/remote/activitypub/act/create.ts
new file mode 100644
index 0000000000..6c62f7ab9e
--- /dev/null
+++ b/src/common/remote/activitypub/act/create.ts
@@ -0,0 +1,9 @@
+import create from '../create';
+
+export default (resolver, actor, activity) => {
+	if ('actor' in activity && actor.account.uri !== activity.actor) {
+		throw new Error;
+	}
+
+	return create(resolver, actor, activity.object);
+};
diff --git a/src/common/remote/activitypub/act/index.ts b/src/common/remote/activitypub/act/index.ts
new file mode 100644
index 0000000000..0f4084a61e
--- /dev/null
+++ b/src/common/remote/activitypub/act/index.ts
@@ -0,0 +1,22 @@
+import create from './create';
+import createObject from '../create';
+import Resolver from '../resolver';
+
+export default (actor, value) => {
+	return (new Resolver).resolve(value).then(resolved => Promise.all(resolved.map(async asyncResult => {
+		const { resolver, object } = await asyncResult;
+		const created = await (await createObject(resolver, actor, [object]))[0];
+
+		if (created !== null) {
+			return created;
+		}
+
+		switch (object.type) {
+		case 'Create':
+			return create(resolver, actor, object);
+
+		default:
+			return null;
+		}
+	})));
+}
diff --git a/src/common/remote/activitypub/create.ts b/src/common/remote/activitypub/create.ts
new file mode 100644
index 0000000000..4aaaeb3060
--- /dev/null
+++ b/src/common/remote/activitypub/create.ts
@@ -0,0 +1,86 @@
+import { JSDOM } from 'jsdom';
+import config from '../../../conf';
+import Post from '../../../models/post';
+import RemoteUserObject, { IRemoteUserObject } from '../../../models/remote-user-object';
+import uploadFromUrl from '../../drive/upload_from_url';
+const createDOMPurify = require('dompurify');
+
+function createRemoteUserObject($ref, $id, { id }) {
+	const object = { $ref, $id };
+
+	if (!id) {
+		return { object };
+	}
+
+	return RemoteUserObject.insert({ uri: id, object });
+}
+
+async function createImage(actor, object) {
+	if ('attributedTo' in object && actor.account.uri !== object.attributedTo) {
+		throw new Error;
+	}
+
+	const { _id } = await uploadFromUrl(object.url, actor);
+	return createRemoteUserObject('driveFiles.files', _id, object);
+}
+
+async function createNote(resolver, actor, object) {
+	if ('attributedTo' in object && actor.account.uri !== object.attributedTo) {
+		throw new Error;
+	}
+
+	const mediaIds = 'attachment' in object &&
+		(await Promise.all(await create(resolver, actor, object.attachment)))
+			.filter(media => media !== null && media.object.$ref === 'driveFiles.files')
+			.map(({ object }) => object.$id);
+
+	const { window } = new JSDOM(object.content);
+
+	const { _id } = await Post.insert({
+		channelId: undefined,
+		index: undefined,
+		createdAt: new Date(object.published),
+		mediaIds,
+		replyId: undefined,
+		repostId: undefined,
+		poll: undefined,
+		text: window.document.body.textContent,
+		textHtml: object.content && createDOMPurify(window).sanitize(object.content),
+		userId: actor._id,
+		appId: null,
+		viaMobile: false,
+		geo: undefined
+	});
+
+	// Register to search database
+	if (object.content && config.elasticsearch.enable) {
+		const es = require('../../db/elasticsearch');
+
+		es.index({
+			index: 'misskey',
+			type: 'post',
+			id: _id.toString(),
+			body: {
+				text: window.document.body.textContent
+			}
+		});
+	}
+
+	return createRemoteUserObject('posts', _id, object);
+}
+
+export default async function create(parentResolver, actor, value): Promise<Promise<IRemoteUserObject>[]> {
+	const results = await parentResolver.resolveRemoteUserObjects(value);
+
+	return results.map(asyncResult => asyncResult.then(({ resolver, object }) => {
+		switch (object.type) {
+		case 'Image':
+			return createImage(actor, object);
+
+		case 'Note':
+			return createNote(resolver, actor, object);
+		}
+
+		return null;
+	}));
+};
diff --git a/src/common/remote/activitypub/resolve-person.ts b/src/common/remote/activitypub/resolve-person.ts
new file mode 100644
index 0000000000..c7c131b0ea
--- /dev/null
+++ b/src/common/remote/activitypub/resolve-person.ts
@@ -0,0 +1,104 @@
+import { JSDOM } from 'jsdom';
+import { toUnicode } from 'punycode';
+import User, { validateUsername, isValidName, isValidDescription } from '../../../models/user';
+import queue from '../../../queue';
+import webFinger from '../webfinger';
+import create from './create';
+import Resolver from './resolver';
+
+async function isCollection(collection) {
+	return ['Collection', 'OrderedCollection'].includes(collection.type);
+}
+
+export default async (value, usernameLower, hostLower, acctLower) => {
+	if (!validateUsername(usernameLower)) {
+		throw new Error;
+	}
+
+	const { resolver, object } = await (new Resolver).resolveOne(value);
+
+	if (
+		object === null ||
+		object.type !== 'Person' ||
+		typeof object.preferredUsername !== 'string' ||
+		object.preferredUsername.toLowerCase() !== usernameLower ||
+		!isValidName(object.name) ||
+		!isValidDescription(object.summary)
+	) {
+		throw new Error;
+	}
+
+	const [followers, following, outbox, finger] = await Promise.all([
+		resolver.resolveOne(object.followers).then(
+			resolved => isCollection(resolved.object) ? resolved.object : null,
+			() => null
+		),
+		resolver.resolveOne(object.following).then(
+			resolved => isCollection(resolved.object) ? resolved.object : null,
+			() => null
+		),
+		resolver.resolveOne(object.outbox).then(
+			resolved => isCollection(resolved.object) ? resolved.object : null,
+			() => null
+		),
+		webFinger(object.id, acctLower),
+	]);
+
+	const summaryDOM = JSDOM.fragment(object.summary);
+
+	// Create user
+	const user = await User.insert({
+		avatarId: null,
+		bannerId: null,
+		createdAt: Date.parse(object.published),
+		description: summaryDOM.textContent,
+		followersCount: followers.totalItem,
+		followingCount: following.totalItem,
+		name: object.name,
+		postsCount: outbox.totalItem,
+		driveCapacity: 1024 * 1024 * 8, // 8MiB
+		username: object.preferredUsername,
+		usernameLower,
+		host: toUnicode(finger.subject.replace(/^.*?@/, '')),
+		hostLower,
+		account: {
+			uri: object.id,
+		},
+	});
+
+	queue.create('http', {
+		type: 'performActivityPub',
+		actor: user._id,
+		outbox
+	}).save();
+
+	const [avatarId, bannerId] = await Promise.all([
+		object.icon,
+		object.image
+	].map(async value => {
+		if (value === undefined) {
+			return null;
+		}
+
+		try {
+			const created = await create(resolver, user, value);
+
+			await Promise.all(created.map(asyncCreated => asyncCreated.then(created => {
+				if (created !== null && created.object.$ref === 'driveFiles.files') {
+					throw created.object.$id;
+				}
+			}, () => {})));
+
+			return null;
+		} catch (id) {
+			return id;
+		}
+	}));
+
+	User.update({ _id: user._id }, { $set: { avatarId, bannerId } });
+
+	user.avatarId = avatarId;
+	user.bannerId = bannerId;
+
+	return user;
+};
diff --git a/src/common/remote/activitypub/resolver.ts b/src/common/remote/activitypub/resolver.ts
new file mode 100644
index 0000000000..50ac1b0b19
--- /dev/null
+++ b/src/common/remote/activitypub/resolver.ts
@@ -0,0 +1,97 @@
+import RemoteUserObject from '../../../models/remote-user-object';
+import { IObject } from './type';
+const request = require('request-promise-native');
+
+type IResult = {
+  resolver: Resolver;
+  object: IObject;
+};
+
+async function resolveUnrequestedOne(this: Resolver, value) {
+	if (typeof value !== 'string') {
+		return { resolver: this, object: value };
+	}
+
+	const resolver = new Resolver(this.requesting);
+
+	resolver.requesting.add(value);
+
+	const object = await request({
+		url: value,
+		headers: {
+			Accept: 'application/activity+json, application/ld+json'
+		},
+		json: true
+	});
+
+	if (object === null || (
+		Array.isArray(object['@context']) ?
+			!object['@context'].includes('https://www.w3.org/ns/activitystreams') :
+			object['@context'] !== 'https://www.w3.org/ns/activitystreams'
+	)) {
+		throw new Error;
+	}
+
+	return { resolver, object };
+}
+
+async function resolveCollection(this: Resolver, value) {
+	if (Array.isArray(value)) {
+		return value;
+	}
+
+	const resolved = typeof value === 'string' ?
+		await resolveUnrequestedOne.call(this, value) :
+		value;
+
+	switch (resolved.type) {
+	case 'Collection':
+		return resolved.items;
+
+	case 'OrderedCollection':
+		return resolved.orderedItems;
+
+	default:
+		return [resolved];
+	}
+}
+
+export default class Resolver {
+	requesting: Set<string>;
+
+	constructor(iterable?: Iterable<string>) {
+		this.requesting = new Set(iterable);
+	}
+
+	async resolve(value): Promise<Promise<IResult>[]> {
+		const collection = await resolveCollection.call(this, value);
+
+		return collection
+			.filter(element => !this.requesting.has(element))
+			.map(resolveUnrequestedOne.bind(this));
+	}
+
+	resolveOne(value) {
+		if (this.requesting.has(value)) {
+			throw new Error;
+		}
+
+		return resolveUnrequestedOne.call(this, value);
+	}
+
+	async resolveRemoteUserObjects(value) {
+		const collection = await resolveCollection.call(this, value);
+
+		return collection.filter(element => !this.requesting.has(element)).map(element => {
+			if (typeof element === 'string') {
+				const object = RemoteUserObject.findOne({ uri: element });
+
+				if (object !== null) {
+					return object;
+				}
+			}
+
+			return resolveUnrequestedOne.call(this, element);
+		});
+	}
+}
diff --git a/src/common/remote/activitypub/type.ts b/src/common/remote/activitypub/type.ts
new file mode 100644
index 0000000000..5c4750e140
--- /dev/null
+++ b/src/common/remote/activitypub/type.ts
@@ -0,0 +1,3 @@
+export type IObject = {
+	type: string;
+}
diff --git a/src/common/remote/resolve-user.ts b/src/common/remote/resolve-user.ts
new file mode 100644
index 0000000000..13d155830e
--- /dev/null
+++ b/src/common/remote/resolve-user.ts
@@ -0,0 +1,26 @@
+import { toUnicode, toASCII } from 'punycode';
+import User from '../../models/user';
+import resolvePerson from './activitypub/resolve-person';
+import webFinger from './webfinger';
+
+export default async (username, host, option) => {
+	const usernameLower = username.toLowerCase();
+	const hostLowerAscii = toASCII(host).toLowerCase();
+	const hostLower = toUnicode(hostLowerAscii);
+
+	let user = await User.findOne({ usernameLower, hostLower }, option);
+
+	if (user === null) {
+		const acctLower = `${usernameLower}@${hostLowerAscii}`;
+
+		const finger = await webFinger(acctLower, acctLower);
+		const self = finger.links.find(link => link.rel && link.rel.toLowerCase() === 'self');
+		if (!self) {
+			throw new Error;
+		}
+
+		user = await resolvePerson(self.href, usernameLower, hostLower, acctLower);
+	}
+
+	return user;
+};
diff --git a/src/common/remote/webfinger.ts b/src/common/remote/webfinger.ts
new file mode 100644
index 0000000000..23f0aaa55f
--- /dev/null
+++ b/src/common/remote/webfinger.ts
@@ -0,0 +1,25 @@
+const WebFinger = require('webfinger.js');
+
+const webFinger = new WebFinger({});
+
+type ILink = {
+  href: string;
+  rel: string;
+}
+
+type IWebFinger = {
+  links: Array<ILink>;
+  subject: string;
+}
+
+export default (query, verifier): Promise<IWebFinger> => new Promise((res, rej) => webFinger.lookup(query, (error, result) => {
+	if (error) {
+		return rej(error);
+	}
+
+	if (result.object.subject.toLowerCase().replace(/^acct:/, '') !== verifier) {
+		return rej('WebFinger verfification failed');
+	}
+
+	res(result.object);
+}));