node-serialport的自定义解析器？

Question

使用像STX(0x02)..Data..ETX(0x03)这样的传入数据

我可以通过byte sequence parser处理数据

var SerialPort = require('serialport');

var port = new SerialPort('/dev/tty-usbserial1', {
  parser: SerialPort.parsers.byteDelimiter([3])
});

port.on('data', function (data) {
  console.log('Data: ' + data);
});

但是我的实际入站数据是STX(0x02)..Data..ETX(0x03)..XX(plus 2 characters to validate data)

如何获取合适的数据？

谢谢!

Answer 1

从node-serialport的版本2或3开始，解析器必须继承Stream.Tansform类。在您的示例中，这将成为一个新类。

创建一个名为CustomParser.js的文件：

class CustomParser extends Transform {
  constructor() {
    super();

    this.incommingData = Buffer.alloc(0);
  }

  _transform(chunk, encoding, cb) {
    // chunk is the incoming buffer here
    this.incommingData = Buffer.concat([this.incommingData, chunk]);
    if (this.incommingData.length > 3 && this.incommingData[this.incommingData.length - 3] == 3) {
        this.push(this.incommingData); // this replaces emitter.emit("data", incomingData);
        this.incommingData = Buffer.alloc(0);
    }
    cb();
  }

  _flush(cb) {
    this.push(this.incommingData);
    this.incommingData = Buffer.alloc(0);
    cb();
  }
}

module.exports = CustomParser;

他们像这样使用你的解析器：

var SerialPort = require('serialport');
var CustomParser = require('./CustomParser ');

var port = new SerialPort('COM1');
var customParser = new CustomParser();
port.pipe(customParser);

customParser.on('data', function(data) {
  console.log(data);
});

Answer 2

解决了！

我编写了自己的解析器：

var SerialPort = require('serialport');
var incommingData = new Buffer(0);
var myParser = function(emitter, buffer) {
    incommingData = Buffer.concat([incommingData, buffer]);
    if (incommingData.length > 3 && incommingData[incommingData.length - 3] == 3) {
        emitter.emit("data", incommingData);
        incommingData = new Buffer(0);
    }
};
var port = new SerialPort('COM1', {parser: myParser});

port.on('data', function(data) {
    console.log(data);
});