node-jet/lib/1_socket/message-socket.js

Jet Realtime Message Bus for the Web. Daemon and Peer implementation.

/* istanbul ignore file */
import { Socket, connect } from 'net';
import { EventEmitter } from './index.js';
/**
 * Class Message socket
 */
export class MessageSocket extends EventEmitter {
    last = Buffer.alloc(0);
    len = -1;
    socket;
    constructor(port, ip = '') {
        super();
        if (port instanceof Socket) {
            this.socket = port;
        }
        else {
            this.socket = connect(port, ip);
            this.socket.on('connect', () => {
                this.emit('open');
            });
        }
        this.socket.on('data', (buf) => {
            let bigBuf = Buffer.concat([this.last, buf]);
            while (true) {
                if (this.len < 0) {
                    if (bigBuf.length < 4) {
                        this.last = bigBuf;
                        return;
                    }
                    else {
                        this.len = bigBuf.readUInt32BE(0);
                        bigBuf = bigBuf.subarray(4);
                    }
                }
                if (this.len > 0) {
                    if (bigBuf.length < this.len) {
                        this.last = bigBuf;
                        return;
                    }
                    else {
                        this.emit('message', bigBuf.toString(undefined, 0, this.len));
                        bigBuf = bigBuf.subarray(this.len);
                        this.len = -1;
                    }
                }
            }
        });
        this.socket.setNoDelay(true);
        this.socket.setKeepAlive(true);
        this.socket.once('close', () => {
            this.emit('close');
        });
        this.socket.once('error', (e) => {
            this.emit('error', e);
        });
    }
    /**
     * Send.
     */
    send(msg) {
        const utf8Length = Buffer.byteLength(msg, 'utf8');
        const buf = Buffer.alloc(4 + utf8Length);
        buf.writeUInt32BE(utf8Length, 0);
        buf.write(msg, 4);
        process.nextTick(() => {
            this.socket.write(buf);
            this.emit('sent', msg);
        });
    }
    /**
     * Close.
     */
    close() {
        this.socket.end();
    }
    /**
     * addEventListener method needed for MessageSocket to be used in the browser.
     * It is a wrapper for plain EventEmitter events like ms.on('...', callback).
     *
     * npm module 'ws' also comes with this method.
     * See https://github.com/websockets/ws/blob/master/lib/WebSocket.js#L410
     * That way we can use node-jet with via browserify inside the browser.
     */
    addEventListener(method, listener) {
        const onMessage = (data) => {
            listener.call(this, new MessageEvent('data', { data }));
        };
        const onClose = (code, message) => {
            listener.call(this, new CloseEvent(code, message));
        };
        const onError = (event) => {
            listener.call(this, event);
        };
        const onOpen = () => {
            listener.call(this, new Event('open'));
        };
        if (typeof listener === 'function') {
            let cb;
            switch (method) {
                case 'message':
                    cb = onMessage;
                    break;
                case 'close':
                    cb = onClose;
                    break;
                case 'error':
                    cb = onError;
                    break;
                case 'open':
                    cb = onOpen;
                    break;
                default:
                    cb = listener;
            }
            this.on(method, cb);
        }
    }
}
export default MessageSocket;