// @ts-check import fs from 'node:fs'; import http from 'node:http'; import path from 'node:path'; import url from 'node:url'; import cors from 'cors'; import dotenv from 'dotenv'; import express from 'express'; import { JSDOM } from 'jsdom'; import { WebSocketServer } from 'ws'; import * as Database from './database.js'; import { AuthenticationError, RequestError, extractStatusAndMessage as extractErrorStatusAndMessage } from './errors.js'; import { logger, httpLogger, initializeLogLevel, attachWebsocketHttpLogger, createWebsocketLogger } from './logging.js'; import { setupMetrics } from './metrics.js'; import * as Redis from './redis.js'; import { isTruthy, normalizeHashtag, firstParam } from './utils.js'; const environment = process.env.NODE_ENV || 'development'; // Correctly detect and load .env or .env.production file based on environment: const dotenvFile = environment === 'production' ? '.env.production' : '.env'; const dotenvFilePath = path.resolve( url.fileURLToPath( new URL(path.join('..', dotenvFile), import.meta.url) ) ); dotenv.config({ path: dotenvFilePath }); initializeLogLevel(process.env, environment); /** * Declares the result type for accountFromToken / accountFromRequest. * * Note: This is here because jsdoc doesn't like importing types that * are nested in functions * @typedef ResolvedAccount * @property {string} accessTokenId * @property {string[]} scopes * @property {string} accountId * @property {string[]} chosenLanguages */ /** * Attempts to safely parse a string as JSON, used when both receiving a message * from redis and when receiving a message from a client over a websocket * connection, this is why it accepts a `req` argument. * @param {string} json * @param {any?} req * @returns {Object.|null} */ const parseJSON = (json, req) => { try { return JSON.parse(json); } catch (err) { /* FIXME: This logging isn't great, and should probably be done at the * call-site of parseJSON, not in the method, but this would require changing * the signature of parseJSON to return something akin to a Result type: * [Error|null, null|Object { const pgPool = Database.getPool(Database.configFromEnv(process.env, environment)); const metrics = setupMetrics(CHANNEL_NAMES, pgPool); const redisConfig = Redis.configFromEnv(process.env); const redisClient = Redis.createClient(redisConfig, logger); const server = http.createServer(); const wss = new WebSocketServer({ noServer: true }); /** * Adds a namespace to Redis keys or channel names * Fixes: https://github.com/redis/ioredis/issues/1910 * @param {string} keyOrChannel * @returns {string} */ function redisNamespaced(keyOrChannel) { if (redisConfig.namespace) { return `${redisConfig.namespace}:${keyOrChannel}`; } else { return keyOrChannel; } } /** * Removes the redis namespace from a channel name * @param {string} channel * @returns {string} */ function redisUnnamespaced(channel) { if (typeof redisConfig.namespace === "string") { // Note: this removes the configured namespace and the colon that is used // to separate it: return channel.slice(redisConfig.namespace.length + 1); } else { return channel; } } // Set the X-Request-Id header on WebSockets: wss.on("headers", function onHeaders(headers, req) { headers.push(`X-Request-Id: ${req.id}`); }); const app = express(); app.set('trust proxy', process.env.TRUSTED_PROXY_IP ? process.env.TRUSTED_PROXY_IP.split(/(?:\s*,\s*|\s+)/) : 'loopback,uniquelocal'); app.use(httpLogger); app.use(cors()); // Handle eventsource & other http requests: server.on('request', app); // Handle upgrade requests: server.on('upgrade', async function handleUpgrade(request, socket, head) { // Setup the HTTP logger, since websocket upgrades don't get the usual http // logger. This decorates the `request` object. attachWebsocketHttpLogger(request); request.log.info("HTTP Upgrade Requested"); /** @param {Error} err */ const onSocketError = (err) => { request.log.error({ error: err }, err.message); }; socket.on('error', onSocketError); /** @type {ResolvedAccount} */ let resolvedAccount; try { resolvedAccount = await accountFromRequest(request); } catch (err) { // Unfortunately for using the on('upgrade') setup, we need to manually // write a HTTP Response to the Socket to close the connection upgrade // attempt, so the following code is to handle all of that. const {statusCode, errorMessage } = extractErrorStatusAndMessage(err); /** @type {Record} */ const headers = { 'Connection': 'close', 'Content-Type': 'text/plain', 'Content-Length': 0, 'X-Request-Id': request.id, 'X-Error-Message': errorMessage }; // Ensure the socket is closed once we've finished writing to it: socket.once('finish', () => { socket.destroy(); }); // Write the HTTP response manually: socket.end(`HTTP/1.1 ${statusCode} ${http.STATUS_CODES[statusCode]}\r\n${Object.keys(headers).map((key) => `${key}: ${headers[key]}`).join('\r\n')}\r\n\r\n`); // Finally, log the error: request.log.error({ err, res: { statusCode, headers } }, errorMessage); return; } // Remove the error handler, wss.handleUpgrade has its own: socket.removeListener('error', onSocketError); wss.handleUpgrade(request, socket, head, function done(ws) { request.log.info("Authenticated request & upgraded to WebSocket connection"); const wsLogger = createWebsocketLogger(request, resolvedAccount); // Start the connection: wss.emit('connection', ws, request, wsLogger); }); }); /** * @type {Object.): void>>} */ const subs = {}; const redisSubscribeClient = Redis.createClient(redisConfig, logger); // When checking metrics in the browser, the favicon is requested this // prevents the request from falling through to the API Router, which would // error for this endpoint: app.get('/favicon.ico', (_req, res) => res.status(404).end()); app.get('/api/v1/streaming/health', (_req, res) => { res.writeHead(200, { 'Content-Type': 'text/plain' }); res.end('OK'); }); app.get('/metrics', metrics.requestHandler); /** * @param {string[]} channels * @returns {function(): void} */ const subscriptionHeartbeat = channels => { const interval = 6 * 60; const tellSubscribed = () => { channels.forEach(channel => redisClient.set(redisNamespaced(`subscribed:${channel}`), '1', 'EX', interval * 3)); }; tellSubscribed(); const heartbeat = setInterval(tellSubscribed, interval * 1000); return () => { clearInterval(heartbeat); }; }; /** * @param {string} channel * @param {string} message */ const onRedisMessage = (channel, message) => { metrics.redisMessagesReceived.inc(); logger.debug(`New message on channel ${channel}`); const key = redisUnnamespaced(channel); const callbacks = subs[key]; if (!callbacks) { return; } const json = parseJSON(message, null); if (!json) return; callbacks.forEach(callback => callback(json)); }; redisSubscribeClient.on("message", onRedisMessage); /** * @callback SubscriptionListener * @param {ReturnType} json of the message * @returns void */ /** * @param {string} channel * @param {SubscriptionListener} callback */ const subscribe = (channel, callback) => { logger.debug(`Adding listener for ${channel}`); subs[channel] = subs[channel] || []; if (subs[channel].length === 0) { logger.debug(`Subscribe ${channel}`); redisSubscribeClient.subscribe(redisNamespaced(channel), (err, count) => { if (err) { logger.error(`Error subscribing to ${channel}`); } else if (typeof count === 'number') { metrics.redisSubscriptions.set(count); } }); } subs[channel].push(callback); }; /** * @param {string} channel * @param {SubscriptionListener} callback */ const unsubscribe = (channel, callback) => { logger.debug(`Removing listener for ${channel}`); if (!subs[channel]) { return; } subs[channel] = subs[channel].filter(item => item !== callback); if (subs[channel].length === 0) { logger.debug(`Unsubscribe ${channel}`); // FIXME: https://github.com/redis/ioredis/issues/1910 redisSubscribeClient.unsubscribe(redisNamespaced(channel), (err, count) => { if (err) { logger.error(`Error unsubscribing to ${channel}`); } else if (typeof count === 'number') { metrics.redisSubscriptions.set(count); } }); delete subs[channel]; } }; /** * @param {http.IncomingMessage & ResolvedAccount} req * @param {string[]} necessaryScopes * @returns {boolean} */ const isInScope = (req, necessaryScopes) => req.scopes.some(scope => necessaryScopes.includes(scope)); /** * @param {string} token * @param {any} req * @returns {Promise} */ const accountFromToken = async (token, req) => { const result = await pgPool.query('SELECT oauth_access_tokens.id, oauth_access_tokens.resource_owner_id, users.account_id, users.chosen_languages, oauth_access_tokens.scopes FROM oauth_access_tokens INNER JOIN users ON oauth_access_tokens.resource_owner_id = users.id WHERE oauth_access_tokens.token = $1 AND oauth_access_tokens.revoked_at IS NULL LIMIT 1', [token]); if (result.rows.length === 0) { throw new AuthenticationError('Invalid access token'); } req.accessTokenId = result.rows[0].id; req.scopes = result.rows[0].scopes.split(' '); req.accountId = result.rows[0].account_id; req.chosenLanguages = result.rows[0].chosen_languages; return { accessTokenId: result.rows[0].id, scopes: result.rows[0].scopes.split(' '), accountId: result.rows[0].account_id, chosenLanguages: result.rows[0].chosen_languages, }; }; /** * @param {any} req * @returns {Promise} */ const accountFromRequest = (req) => new Promise((resolve, reject) => { const authorization = req.headers.authorization; const location = url.parse(req.url, true); const accessToken = location.query.access_token || req.headers['sec-websocket-protocol']; if (!authorization && !accessToken) { reject(new AuthenticationError('Missing access token')); return; } const token = authorization ? authorization.replace(/^Bearer /, '') : accessToken; resolve(accountFromToken(token, req)); }); /** * @param {any} req * @returns {string|undefined} */ const channelNameFromPath = req => { const { path, query } = req; const onlyMedia = isTruthy(query.only_media); switch (path) { case '/api/v1/streaming/user': return 'user'; case '/api/v1/streaming/user/notification': return 'user:notification'; case '/api/v1/streaming/public': return onlyMedia ? 'public:media' : 'public'; case '/api/v1/streaming/public/local': return onlyMedia ? 'public:local:media' : 'public:local'; case '/api/v1/streaming/public/remote': return onlyMedia ? 'public:remote:media' : 'public:remote'; case '/api/v1/streaming/hashtag': return 'hashtag'; case '/api/v1/streaming/hashtag/local': return 'hashtag:local'; case '/api/v1/streaming/direct': return 'direct'; case '/api/v1/streaming/list': return 'list'; default: return undefined; } }; /** * @param {http.IncomingMessage & ResolvedAccount} req * @param {import('pino').Logger} logger * @param {string|undefined} channelName * @returns {Promise.} */ const checkScopes = (req, logger, channelName) => new Promise((resolve, reject) => { logger.debug(`Checking OAuth scopes for ${channelName}`); // When accessing public channels, no scopes are needed if (channelName && PUBLIC_CHANNELS.includes(channelName)) { resolve(); return; } // The `read` scope has the highest priority, if the token has it // then it can access all streams const requiredScopes = ['read']; // When accessing specifically the notifications stream, // we need a read:notifications, while in all other cases, // we can allow access with read:statuses. Mind that the // user stream will not contain notifications unless // the token has either read or read:notifications scope // as well, this is handled separately. if (channelName === 'user:notification') { requiredScopes.push('read:notifications'); } else { requiredScopes.push('read:statuses'); } if (req.scopes && requiredScopes.some(requiredScope => req.scopes.includes(requiredScope))) { resolve(); return; } reject(new AuthenticationError('Access token does not have the required scopes')); }); /** * @typedef SystemMessageHandlers * @property {function(): void} onKill */ /** * @param {any} req * @param {SystemMessageHandlers} eventHandlers * @returns {SubscriptionListener} */ const createSystemMessageListener = (req, eventHandlers) => { return message => { if (!message?.event) { return; } const { event } = message; req.log.debug(`System message for ${req.accountId}: ${event}`); if (event === 'kill') { req.log.debug(`Closing connection for ${req.accountId} due to expired access token`); eventHandlers.onKill(); } else if (event === 'filters_changed') { req.log.debug(`Invalidating filters cache for ${req.accountId}`); req.cachedFilters = null; } }; }; /** * @param {http.IncomingMessage & ResolvedAccount} req * @param {http.OutgoingMessage} res */ const subscribeHttpToSystemChannel = (req, res) => { const accessTokenChannelId = `timeline:access_token:${req.accessTokenId}`; const systemChannelId = `timeline:system:${req.accountId}`; const listener = createSystemMessageListener(req, { onKill() { res.end(); }, }); res.on('close', () => { unsubscribe(accessTokenChannelId, listener); unsubscribe(systemChannelId, listener); metrics.connectedChannels.labels({ type: 'eventsource', channel: 'system' }).dec(2); }); subscribe(accessTokenChannelId, listener); subscribe(systemChannelId, listener); metrics.connectedChannels.labels({ type: 'eventsource', channel: 'system' }).inc(2); }; /** * @param {any} req * @param {any} res * @param {function(Error=): void} next */ const authenticationMiddleware = (req, res, next) => { if (req.method === 'OPTIONS') { next(); return; } const channelName = channelNameFromPath(req); // If no channelName can be found for the request, then we should terminate // the connection, as there's nothing to stream back if (!channelName) { next(new RequestError('Unknown channel requested')); return; } accountFromRequest(req).then(() => checkScopes(req, req.log, channelName)).then(() => { subscribeHttpToSystemChannel(req, res); }).then(() => { next(); }).catch(err => { next(err); }); }; /** * @param {Error} err * @param {any} req * @param {any} res * @param {function(Error=): void} next */ const errorMiddleware = (err, req, res, next) => { req.log.error({ err }, err.toString()); if (res.headersSent) { next(err); return; } const {statusCode, errorMessage } = extractErrorStatusAndMessage(err); res.writeHead(statusCode, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: errorMessage })); }; /** * @param {any[]} arr * @param {number=} shift * @returns {string} */ // @ts-ignore const placeholders = (arr, shift = 0) => arr.map((_, i) => `$${i + 1 + shift}`).join(', '); /** * @param {string} listId * @param {any} req * @returns {Promise.} */ const authorizeListAccess = async (listId, req) => { const { accountId } = req; const result = await pgPool.query('SELECT id, account_id FROM lists WHERE id = $1 AND account_id = $2 LIMIT 1', [listId, accountId]); if (result.rows.length === 0) { throw new AuthenticationError('List not found'); } }; /** * @param {string[]} channelIds * @param {http.IncomingMessage & ResolvedAccount} req * @param {import('pino').Logger} log * @param {function(string, string): void} output * @param {undefined | function(string[], SubscriptionListener): void} attachCloseHandler * @param {'websocket' | 'eventsource'} destinationType * @param {boolean=} needsFiltering * @returns {SubscriptionListener} */ const streamFrom = (channelIds, req, log, output, attachCloseHandler, destinationType, needsFiltering = false) => { log.info({ channelIds }, `Starting stream`); /** * @param {string} event * @param {object|string} payload */ const transmit = (event, payload) => { // TODO: Replace "string"-based delete payloads with object payloads: const encodedPayload = typeof payload === 'object' ? JSON.stringify(payload) : payload; metrics.messagesSent.labels({ type: destinationType }).inc(1); log.debug({ event, payload }, `Transmitting ${event} to ${req.accountId}`); output(event, encodedPayload); }; // The listener used to process each message off the redis subscription, // message here is an object with an `event` and `payload` property. Some // events also include a queued_at value, but this is being removed shortly. /** @type {SubscriptionListener} */ const listener = message => { if (!message?.event || !message?.payload) { return; } const { event, payload } = message; // Streaming only needs to apply filtering to some channels and only to // some events. This is because majority of the filtering happens on the // Ruby on Rails side when producing the event for streaming. // // The only events that require filtering from the streaming server are // `update` and `status.update`, all other events are transmitted to the // client as soon as they're received (pass-through). // // The channels that need filtering are determined in the function // `channelNameToIds` defined below: if (!needsFiltering || (event !== 'update' && event !== 'status.update')) { transmit(event, payload); return; } // The rest of the logic from here on in this function is to handle // filtering of statuses: // Filter based on language: if (Array.isArray(req.chosenLanguages) && payload.language !== null && req.chosenLanguages.indexOf(payload.language) === -1) { log.debug(`Message ${payload.id} filtered by language (${payload.language})`); return; } // When the account is not logged in, it is not necessary to confirm the block or mute if (!req.accountId) { transmit(event, payload); return; } // Filter based on domain blocks, blocks, mutes, or custom filters: // @ts-ignore const targetAccountIds = [payload.account.id].concat(payload.mentions.map(item => item.id)); const accountDomain = payload.account.acct.split('@')[1]; // TODO: Move this logic out of the message handling loop pgPool.connect((err, client, releasePgConnection) => { if (err) { log.error(err); return; } const queries = [ // @ts-ignore client.query(`SELECT 1 FROM blocks WHERE (account_id = $1 AND target_account_id IN (${placeholders(targetAccountIds, 2)})) OR (account_id = $2 AND target_account_id = $1) UNION SELECT 1 FROM mutes WHERE account_id = $1 AND target_account_id IN (${placeholders(targetAccountIds, 2)})`, [req.accountId, payload.account.id].concat(targetAccountIds)), ]; if (accountDomain) { // @ts-ignore queries.push(client.query('SELECT 1 FROM account_domain_blocks WHERE account_id = $1 AND domain = $2', [req.accountId, accountDomain])); } // @ts-ignore if (!payload.filtered && !req.cachedFilters) { // @ts-ignore queries.push(client.query('SELECT filter.id AS id, filter.phrase AS title, filter.context AS context, filter.expires_at AS expires_at, filter.action AS filter_action, keyword.keyword AS keyword, keyword.whole_word AS whole_word FROM custom_filter_keywords keyword JOIN custom_filters filter ON keyword.custom_filter_id = filter.id WHERE filter.account_id = $1 AND (filter.expires_at IS NULL OR filter.expires_at > NOW())', [req.accountId])); } Promise.all(queries).then(values => { releasePgConnection(); // Handling blocks & mutes and domain blocks: If one of those applies, // then we don't transmit the payload of the event to the client if (values[0].rows.length > 0 || (accountDomain && values[1].rows.length > 0)) { return; } // If the payload already contains the `filtered` property, it means // that filtering has been applied on the ruby on rails side, as // such, we don't need to construct or apply the filters in streaming: if (Object.hasOwn(payload, "filtered")) { transmit(event, payload); return; } // Handling for constructing the custom filters and caching them on the request // TODO: Move this logic out of the message handling lifecycle // @ts-ignore if (!req.cachedFilters) { const filterRows = values[accountDomain ? 2 : 1].rows; // @ts-ignore req.cachedFilters = filterRows.reduce((cache, filter) => { if (cache[filter.id]) { cache[filter.id].keywords.push([filter.keyword, filter.whole_word]); } else { cache[filter.id] = { keywords: [[filter.keyword, filter.whole_word]], expires_at: filter.expires_at, filter: { id: filter.id, title: filter.title, context: filter.context, expires_at: filter.expires_at, // filter.filter_action is the value from the // custom_filters.action database column, it is an integer // representing a value in an enum defined by Ruby on Rails: // // enum { warn: 0, hide: 1 } filter_action: ['warn', 'hide'][filter.filter_action], }, }; } return cache; }, {}); // Construct the regular expressions for the custom filters: This // needs to be done in a separate loop as the database returns one // filterRow per keyword, so we need all the keywords before // constructing the regular expression // @ts-ignore Object.keys(req.cachedFilters).forEach((key) => { // @ts-ignore req.cachedFilters[key].regexp = new RegExp(req.cachedFilters[key].keywords.map(([keyword, whole_word]) => { let expr = keyword.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); if (whole_word) { if (/^[\w]/.test(expr)) { expr = `\\b${expr}`; } if (/[\w]$/.test(expr)) { expr = `${expr}\\b`; } } return expr; }).join('|'), 'i'); }); } // Apply cachedFilters against the payload, constructing a // `filter_results` array of FilterResult entities // @ts-ignore if (req.cachedFilters) { const status = payload; // TODO: Calculate searchableContent in Ruby on Rails: // @ts-ignore const searchableContent = ([status.spoiler_text || '', status.content].concat((status.poll && status.poll.options) ? status.poll.options.map(option => option.title) : [])).concat(status.media_attachments.map(att => att.description)).join('\n\n').replace(//g, '\n').replace(/<\/p>

/g, '\n\n'); const searchableTextContent = JSDOM.fragment(searchableContent).textContent; const now = new Date(); // @ts-ignore const filter_results = Object.values(req.cachedFilters).reduce((results, cachedFilter) => { // Check the filter hasn't expired before applying: if (cachedFilter.expires_at !== null && cachedFilter.expires_at < now) { return results; } // Just in-case JSDOM fails to find textContent in searchableContent if (!searchableTextContent) { return results; } const keyword_matches = searchableTextContent.match(cachedFilter.regexp); if (keyword_matches) { // results is an Array of FilterResult; status_matches is always // null as we only are only applying the keyword-based custom // filters, not the status-based custom filters. // https://docs.joinmastodon.org/entities/FilterResult/ results.push({ filter: cachedFilter.filter, keyword_matches, status_matches: null }); } return results; }, []); // Send the payload + the FilterResults as the `filtered` property // to the streaming connection. To reach this code, the `event` must // have been either `update` or `status.update`, meaning the // `payload` is a Status entity, which has a `filtered` property: // // filtered: https://docs.joinmastodon.org/entities/Status/#filtered transmit(event, { ...payload, filtered: filter_results }); } else { transmit(event, payload); } }).catch(err => { log.error(err); releasePgConnection(); }); }); }; channelIds.forEach(id => { subscribe(id, listener); }); if (typeof attachCloseHandler === 'function') { attachCloseHandler(channelIds, listener); } return listener; }; /** * @param {any} req * @param {any} res * @returns {function(string, string): void} */ const streamToHttp = (req, res) => { const channelName = channelNameFromPath(req); metrics.connectedClients.labels({ type: 'eventsource' }).inc(); // In theory we'll always have a channel name, but channelNameFromPath can return undefined: if (typeof channelName === 'string') { metrics.connectedChannels.labels({ type: 'eventsource', channel: channelName }).inc(); } res.setHeader('Content-Type', 'text/event-stream'); res.setHeader('Cache-Control', 'no-store'); res.setHeader('Transfer-Encoding', 'chunked'); res.write(':)\n'); const heartbeat = setInterval(() => res.write(':thump\n'), 15000); req.on('close', () => { req.log.info({ accountId: req.accountId }, `Ending stream`); // We decrement these counters here instead of in streamHttpEnd as in that // method we don't have knowledge of the channel names metrics.connectedClients.labels({ type: 'eventsource' }).dec(); // In theory we'll always have a channel name, but channelNameFromPath can return undefined: if (typeof channelName === 'string') { metrics.connectedChannels.labels({ type: 'eventsource', channel: channelName }).dec(); } clearInterval(heartbeat); }); return (event, payload) => { res.write(`event: ${event}\n`); res.write(`data: ${payload}\n\n`); }; }; /** * @param {any} req * @param {function(): void} [closeHandler] * @returns {function(string[], SubscriptionListener): void} */ const streamHttpEnd = (req, closeHandler = undefined) => (ids, listener) => { req.on('close', () => { ids.forEach(id => { unsubscribe(id, listener); }); if (closeHandler) { closeHandler(); } }); }; /** * @param {http.IncomingMessage} req * @param {import('ws').WebSocket} ws * @param {string[]} streamName * @returns {function(string, string): void} */ const streamToWs = (req, ws, streamName) => (event, payload) => { if (ws.readyState !== ws.OPEN) { req.log.error('Tried writing to closed socket'); return; } const message = JSON.stringify({ stream: streamName, event, payload }); ws.send(message, (/** @type {Error|undefined} */ err) => { if (err) { req.log.error({err}, `Failed to send to websocket`); } }); }; /** * @param {http.ServerResponse} res */ const httpNotFound = res => { res.writeHead(404, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: 'Not found' })); }; const api = express.Router(); app.use(api); api.use(authenticationMiddleware); api.use(errorMiddleware); api.get('/api/v1/streaming/*', (req, res) => { const channelName = channelNameFromPath(req); // FIXME: In theory we'd never actually reach here due to // authenticationMiddleware catching this case, however, we need to refactor // how those middlewares work, so I'm adding the extra check in here. if (!channelName) { httpNotFound(res); return; } channelNameToIds(req, channelName, req.query).then(({ channelIds, options }) => { const onSend = streamToHttp(req, res); const onEnd = streamHttpEnd(req, subscriptionHeartbeat(channelIds)); // @ts-ignore streamFrom(channelIds, req, req.log, onSend, onEnd, 'eventsource', options.needsFiltering); }).catch(err => { const {statusCode, errorMessage } = extractErrorStatusAndMessage(err); res.log.info({ err }, 'Eventsource subscription error'); res.writeHead(statusCode, { 'Content-Type': 'application/json' }); res.end(JSON.stringify({ error: errorMessage })); }); }); /** * @typedef StreamParams * @property {string} [tag] * @property {string} [list] * @property {string} [only_media] */ /** * @param {any} req * @returns {string[]} */ const channelsForUserStream = req => { const arr = [`timeline:${req.accountId}`]; if (isInScope(req, ['read', 'read:notifications'])) { arr.push(`timeline:${req.accountId}:notifications`); } return arr; }; /** * @param {any} req * @param {string} name * @param {StreamParams} params * @returns {Promise.<{ channelIds: string[], options: { needsFiltering: boolean } }>} */ const channelNameToIds = (req, name, params) => new Promise((resolve, reject) => { switch (name) { case 'user': resolve({ channelIds: channelsForUserStream(req), options: { needsFiltering: false }, }); break; case 'user:notification': resolve({ channelIds: [`timeline:${req.accountId}:notifications`], options: { needsFiltering: false }, }); break; case 'public': resolve({ channelIds: ['timeline:public'], options: { needsFiltering: true }, }); break; case 'public:local': resolve({ channelIds: ['timeline:public:local'], options: { needsFiltering: true }, }); break; case 'public:remote': resolve({ channelIds: ['timeline:public:remote'], options: { needsFiltering: true }, }); break; case 'public:media': resolve({ channelIds: ['timeline:public:media'], options: { needsFiltering: true }, }); break; case 'public:local:media': resolve({ channelIds: ['timeline:public:local:media'], options: { needsFiltering: true }, }); break; case 'public:remote:media': resolve({ channelIds: ['timeline:public:remote:media'], options: { needsFiltering: true }, }); break; case 'direct': resolve({ channelIds: [`timeline:direct:${req.accountId}`], options: { needsFiltering: false }, }); break; case 'hashtag': if (!params.tag) { reject(new RequestError('Missing tag name parameter')); } else { resolve({ channelIds: [`timeline:hashtag:${normalizeHashtag(params.tag)}`], options: { needsFiltering: true }, }); } break; case 'hashtag:local': if (!params.tag) { reject(new RequestError('Missing tag name parameter')); } else { resolve({ channelIds: [`timeline:hashtag:${normalizeHashtag(params.tag)}:local`], options: { needsFiltering: true }, }); } break; case 'list': if (!params.list) { reject(new RequestError('Missing list name parameter')); return; } authorizeListAccess(params.list, req).then(() => { resolve({ channelIds: [`timeline:list:${params.list}`], options: { needsFiltering: false }, }); }).catch(() => { reject(new AuthenticationError('Not authorized to stream this list')); }); break; default: reject(new RequestError('Unknown stream type')); } }); /** * @param {string} channelName * @param {StreamParams} params * @returns {string[]} */ const streamNameFromChannelName = (channelName, params) => { if (channelName === 'list' && params.list) { return [channelName, params.list]; } else if (['hashtag', 'hashtag:local'].includes(channelName) && params.tag) { return [channelName, params.tag]; } else { return [channelName]; } }; /** * @typedef WebSocketSession * @property {import('ws').WebSocket & { isAlive: boolean}} websocket * @property {http.IncomingMessage & ResolvedAccount} request * @property {import('pino').Logger} logger * @property {Object.} subscriptions */ /** * @param {WebSocketSession} session * @param {string} channelName * @param {StreamParams} params * @returns {void} */ const subscribeWebsocketToChannel = ({ websocket, request, logger, subscriptions }, channelName, params) => { checkScopes(request, logger, channelName).then(() => channelNameToIds(request, channelName, params)).then(({ channelIds, options, }) => { if (subscriptions[channelIds.join(';')]) { return; } const onSend = streamToWs(request, websocket, streamNameFromChannelName(channelName, params)); const stopHeartbeat = subscriptionHeartbeat(channelIds); const listener = streamFrom(channelIds, request, logger, onSend, undefined, 'websocket', options.needsFiltering); metrics.connectedChannels.labels({ type: 'websocket', channel: channelName }).inc(); subscriptions[channelIds.join(';')] = { channelName, listener, stopHeartbeat, }; }).catch(err => { const {statusCode, errorMessage } = extractErrorStatusAndMessage(err); logger.error({ err }, 'Websocket subscription error'); // If we have a socket that is alive and open still, send the error back to the client: if (websocket.isAlive && websocket.readyState === websocket.OPEN) { websocket.send(JSON.stringify({ error: errorMessage, status: statusCode })); } }); }; /** * @param {WebSocketSession} session * @param {string[]} channelIds */ const removeSubscription = ({ request, logger, subscriptions }, channelIds) => { logger.info({ channelIds, accountId: request.accountId }, `Ending stream`); const subscription = subscriptions[channelIds.join(';')]; if (!subscription) { return; } channelIds.forEach(channelId => { unsubscribe(channelId, subscription.listener); }); metrics.connectedChannels.labels({ type: 'websocket', channel: subscription.channelName }).dec(); subscription.stopHeartbeat(); delete subscriptions[channelIds.join(';')]; }; /** * @param {WebSocketSession} session * @param {string} channelName * @param {StreamParams} params * @returns {void} */ const unsubscribeWebsocketFromChannel = (session, channelName, params) => { const { websocket, request, logger } = session; channelNameToIds(request, channelName, params).then(({ channelIds }) => { removeSubscription(session, channelIds); }).catch(err => { logger.error({err}, 'Websocket unsubscribe error'); // If we have a socket that is alive and open still, send the error back to the client: if (websocket.isAlive && websocket.readyState === websocket.OPEN) { // TODO: Use a better error response here websocket.send(JSON.stringify({ error: "Error unsubscribing from channel" })); } }); }; /** * @param {WebSocketSession} session */ const subscribeWebsocketToSystemChannel = ({ websocket, request, subscriptions }) => { const accessTokenChannelId = `timeline:access_token:${request.accessTokenId}`; const systemChannelId = `timeline:system:${request.accountId}`; const listener = createSystemMessageListener(request, { onKill() { websocket.close(); }, }); subscribe(accessTokenChannelId, listener); subscribe(systemChannelId, listener); subscriptions[accessTokenChannelId] = { channelName: 'system', listener, stopHeartbeat: () => { }, }; subscriptions[systemChannelId] = { channelName: 'system', listener, stopHeartbeat: () => { }, }; metrics.connectedChannels.labels({ type: 'websocket', channel: 'system' }).inc(2); }; /** * @param {import('ws').WebSocket & { isAlive: boolean }} ws * @param {http.IncomingMessage & ResolvedAccount} req * @param {import('pino').Logger} log */ function onConnection(ws, req, log) { // Note: url.parse could throw, which would terminate the connection, so we // increment the connected clients metric straight away when we establish // the connection, without waiting: metrics.connectedClients.labels({ type: 'websocket' }).inc(); // Setup connection keep-alive state: ws.isAlive = true; ws.on('pong', () => { ws.isAlive = true; }); /** * @type {WebSocketSession} */ const session = { websocket: ws, request: req, logger: log, subscriptions: {}, }; ws.on('close', function onWebsocketClose() { const subscriptions = Object.keys(session.subscriptions); subscriptions.forEach(channelIds => { removeSubscription(session, channelIds.split(';')); }); // Decrement the metrics for connected clients: metrics.connectedClients.labels({ type: 'websocket' }).dec(); // We need to unassign the session object as to ensure it correctly gets // garbage collected, without doing this we could accidentally hold on to // references to the websocket, the request, and the logger, causing // memory leaks. // This is commented out because `delete` only operated on object properties // It needs to be replaced by `session = undefined`, but it requires every calls to // `session` to check for it, thus a significant refactor // delete session; }); // Note: immediately after the `error` event is emitted, the `close` event // is emitted. As such, all we need to do is log the error here. ws.on('error', (/** @type {Error} */ err) => { log.error(err); }); ws.on('message', (data, isBinary) => { if (isBinary) { log.warn('Received binary data, closing connection'); ws.close(1003, 'The mastodon streaming server does not support binary messages'); return; } const message = data.toString('utf8'); const json = parseJSON(message, session.request); if (!json) return; const { type, stream, ...params } = json; if (type === 'subscribe') { subscribeWebsocketToChannel(session, firstParam(stream), params); } else if (type === 'unsubscribe') { unsubscribeWebsocketFromChannel(session, firstParam(stream), params); } else { // Unknown action type } }); subscribeWebsocketToSystemChannel(session); // Parse the URL for the connection arguments (if supplied), url.parse can throw: const location = req.url && url.parse(req.url, true); if (location && location.query.stream) { subscribeWebsocketToChannel(session, firstParam(location.query.stream), location.query); } } wss.on('connection', onConnection); setInterval(() => { wss.clients.forEach(ws => { // @ts-ignore if (ws.isAlive === false) { ws.terminate(); return; } // @ts-ignore ws.isAlive = false; ws.ping('', false); }); }, 30000); attachServerWithConfig(server, address => { logger.info(`Streaming API now listening on ${address}`); }); const onExit = () => { server.close(); process.exit(0); }; /** @param {Error} err */ const onError = (err) => { logger.error(err); server.close(); process.exit(0); }; process.on('SIGINT', onExit); process.on('SIGTERM', onExit); process.on('exit', onExit); process.on('uncaughtException', onError); }; /** * @param {any} server * @param {function(string): void} [onSuccess] */ const attachServerWithConfig = (server, onSuccess) => { if (process.env.SOCKET) { server.listen(process.env.SOCKET, () => { if (onSuccess) { fs.chmodSync(server.address(), 0o666); onSuccess(server.address()); } }); } else { const port = +(process.env.PORT || 4000); let bind = process.env.BIND ?? '127.0.0.1'; // Web uses the URI syntax for BIND, which means IPv6 addresses may // be wrapped in square brackets: if (bind.startsWith('[') && bind.endsWith(']')) { bind = bind.slice(1, -1); } server.listen(port, bind, () => { if (onSuccess) { onSuccess(`${server.address().address}:${server.address().port}`); } }); } }; startServer();