import autobind from 'autobind-decorator'; import { EventEmitter } from 'eventemitter3'; import ReconnectingWebsocket from 'reconnecting-websocket'; import { stringify } from 'querystring'; import { BroadcastEvents, Channels } from './streaming.types'; function urlQuery(obj: {}): string { return stringify(Object.entries(obj) .filter(([, v]) => Array.isArray(v) ? v.length : v !== undefined) .reduce((a, [k, v]) => (a[k] = v, a), {} as Record)); } type AnyOf> = T[keyof T]; type StreamEvents = { _connected_: void; _disconnected_: void; } & BroadcastEvents; /** * Misskey stream connection */ export default class Stream extends EventEmitter { private stream: ReconnectingWebsocket; public state: 'initializing' | 'reconnecting' | 'connected' = 'initializing'; private sharedConnectionPools: Pool[] = []; private sharedConnections: SharedConnection[] = []; private nonSharedConnections: NonSharedConnection[] = []; private idCounter = 0; constructor(origin: string, user: { token: string; } | null, options?: { WebSocket?: any; }) { super(); options = options || { }; const query = urlQuery({ i: user?.token, // To prevent cache of an HTML such as error screen _t: Date.now(), }); const wsOrigin = origin.replace('http://', 'ws://').replace('https://', 'wss://'); this.stream = new ReconnectingWebsocket(`${wsOrigin}/streaming?${query}`, '', { minReconnectionDelay: 1, // https://github.com/pladaria/reconnecting-websocket/issues/91 WebSocket: options.WebSocket }); this.stream.addEventListener('open', this.onOpen); this.stream.addEventListener('close', this.onClose); this.stream.addEventListener('message', this.onMessage); } @autobind private genId(): string { return (++this.idCounter).toString(); } @autobind public useChannel(channel: C, params?: Channels[C]['params'], name?: string): Connection { if (params) { return this.connectToChannel(channel, params); } else { return this.useSharedConnection(channel, name); } } @autobind private useSharedConnection(channel: C, name?: string): SharedConnection { let pool = this.sharedConnectionPools.find(p => p.channel === channel); if (pool == null) { pool = new Pool(this, channel, this.genId()); this.sharedConnectionPools.push(pool); } const connection = new SharedConnection(this, channel, pool, name); this.sharedConnections.push(connection); return connection; } @autobind public removeSharedConnection(connection: SharedConnection) { this.sharedConnections = this.sharedConnections.filter(c => c !== connection); } @autobind public removeSharedConnectionPool(pool: Pool) { this.sharedConnectionPools = this.sharedConnectionPools.filter(p => p !== pool); } @autobind private connectToChannel(channel: C, params: Channels[C]['params']): NonSharedConnection { const connection = new NonSharedConnection(this, channel, this.genId(), params); this.nonSharedConnections.push(connection); return connection; } @autobind public disconnectToChannel(connection: NonSharedConnection) { this.nonSharedConnections = this.nonSharedConnections.filter(c => c !== connection); } /** * Callback of when open connection */ @autobind private onOpen() { const isReconnect = this.state === 'reconnecting'; this.state = 'connected'; this.emit('_connected_'); // チャンネル再接続 if (isReconnect) { for (const p of this.sharedConnectionPools) p.connect(); for (const c of this.nonSharedConnections) c.connect(); } } /** * Callback of when close connection */ @autobind private onClose() { if (this.state === 'connected') { this.state = 'reconnecting'; this.emit('_disconnected_'); } } /** * Callback of when received a message from connection */ @autobind private onMessage(message: { data: string; }) { const { type, body } = JSON.parse(message.data); if (type === 'channel') { const id = body.id; let connections: Connection[]; connections = this.sharedConnections.filter(c => c.id === id); if (connections.length === 0) { const found = this.nonSharedConnections.find(c => c.id === id); if (found) { connections = [found]; } } for (const c of connections.filter(c => c != null)) { c.emit(body.type, Object.freeze(body.body)); c.inCount++; } } else { this.emit(type, Object.freeze(body)); } } /** * Send a message to connection */ @autobind public send(typeOrPayload: any, payload?: any) { const data = payload === undefined ? typeOrPayload : { type: typeOrPayload, body: payload }; this.stream.send(JSON.stringify(data)); } /** * Close this connection */ @autobind public close() { this.stream.close(); } } // TODO: これらのクラスを Stream クラスの内部クラスにすれば余計なメンバをpublicにしないで済むかも? // もしくは @internal を使う? https://www.typescriptlang.org/tsconfig#stripInternal class Pool { public channel: string; public id: string; protected stream: Stream; public users = 0; private disposeTimerId: any; private isConnected = false; constructor(stream: Stream, channel: string, id: string) { this.channel = channel; this.stream = stream; this.id = id; this.stream.on('_disconnected_', this.onStreamDisconnected); } @autobind private onStreamDisconnected() { this.isConnected = false; } @autobind public inc() { if (this.users === 0 && !this.isConnected) { this.connect(); } this.users++; // タイマー解除 if (this.disposeTimerId) { clearTimeout(this.disposeTimerId); this.disposeTimerId = null; } } @autobind public dec() { this.users--; // そのコネクションの利用者が誰もいなくなったら if (this.users === 0) { // また直ぐに再利用される可能性があるので、一定時間待ち、 // 新たな利用者が現れなければコネクションを切断する this.disposeTimerId = setTimeout(() => { this.disconnect(); }, 3000); } } @autobind public connect() { if (this.isConnected) return; this.isConnected = true; this.stream.send('connect', { channel: this.channel, id: this.id }); } @autobind private disconnect() { this.stream.off('_disconnected_', this.onStreamDisconnected); this.stream.send('disconnect', { id: this.id }); this.stream.removeSharedConnectionPool(this); } } abstract class Connection = any> extends EventEmitter { public channel: string; protected stream: Stream; public abstract id: string; public name?: string; // for debug public inCount: number = 0; // for debug public outCount: number = 0; // for debug constructor(stream: Stream, channel: string, name?: string) { super(); this.stream = stream; this.channel = channel; this.name = name; } @autobind public send(type: T, body: Channel['receives'][T]) { this.stream.send('ch', { id: this.id, type: type, body: body }); this.outCount++; } public abstract dispose(): void; } class SharedConnection = any> extends Connection { private pool: Pool; public get id(): string { return this.pool.id; } constructor(stream: Stream, channel: string, pool: Pool, name?: string) { super(stream, channel, name); this.pool = pool; this.pool.inc(); } @autobind public dispose() { this.pool.dec(); this.removeAllListeners(); this.stream.removeSharedConnection(this); } } class NonSharedConnection = any> extends Connection { public id: string; protected params: Channel['params']; constructor(stream: Stream, channel: string, id: string, params: Channel['params']) { super(stream, channel); this.params = params; this.id = id; this.connect(); } @autobind public connect() { this.stream.send('connect', { channel: this.channel, id: this.id, params: this.params }); } @autobind public dispose() { this.removeAllListeners(); this.stream.send('disconnect', { id: this.id }); this.stream.disconnectToChannel(this); } }