node-fxplc/dist/esm/TransportSerial.js

Node.js library for low-level Mitsubishi FX (MELSEC) PLC framed protocol communication

// TransportSerial.js - Serial transport implementation using BufferAccumulator.
import { NoResponseError, NotConnectedError } from './errors.js';
import { BufferAccumulator } from './transport-buffer.js';
export class TransportSerial {
    /**
     * @param {object} opts
     * @param {string} opts.path Serial device path (e.g. COM3, /dev/ttyUSB0)
     * @param {number} [opts.baudRate=9600] Baud rate
     * @param {number} [opts.timeout=1000] Read timeout in ms
     */
    constructor({ path, baudRate = 9600, timeout = 1000 }) {
        this.path = path;
        this.baudRate = baudRate;
        this.timeout = timeout;
        this._opened = false;
        this._port = null;
        this._bufferAcc = new BufferAccumulator();
    }
    /** Lazily open the serial port */
    async _ensureOpen() {
        if (this._opened)
            return;
        let SerialPort;
        try {
            ({ SerialPort } = await import('serialport'));
        }
        catch {
            throw new Error("Dipendenza 'serialport' non installata o non disponibile");
        }
        await new Promise((resolve, reject) => {
            const port = new SerialPort({
                path: this.path,
                baudRate: this.baudRate,
                dataBits: 7,
                stopBits: 1,
                parity: 'even',
                autoOpen: true,
                lock: false,
            }, err => { if (err)
                return reject(err); resolve(); });
            this._port = port;
            port.on('data', d => this._bufferAcc.push(d));
            port.on('error', () => this.close());
            port.on('close', () => this._bufferAcc.close());
        });
        this._opened = true;
    }
    /** Write raw frame data; resets accumulator before each request */
    async write(data) {
        await this._ensureOpen();
        if (!this._port)
            throw new NotConnectedError();
        // reset buffer logico prima della richiesta
        this._bufferAcc = new BufferAccumulator();
        await new Promise((resolve, reject) => this._port.write(data, err => err ? reject(err) : resolve()));
    }
    /** Read bytes from buffer accumulator */
    async read(size) {
        await this._ensureOpen();
        if (!this._port)
            throw new NotConnectedError();
        try {
            return await this._bufferAcc.read(size, this.timeout);
        }
        catch {
            throw new NoResponseError();
        }
    }
    /** Close port (idempotent) */
    close() {
        if (this._port) {
            try {
                this._port.close();
            }
            catch { /*noop*/ }
            this._port = null;
        }
        this._opened = false;
        this._bufferAcc.close();
    }
}