Readline分析器无法从串行端口正确读取-NodeJS

Question

我与POS（销售点）设备连接。我以十六进制代码发送信息，设备打印出收据。 我的问题是解析器（Readline）无法正常工作。当我尝试使用parser.on("data", console.log)时，它不会返回任何内容。 这是我的代码：

const SerialPort = require('serialport');// include the library
const WebSocketServer = require('ws').Server;
const SERVER_PORT = 7000;               // port number for the webSocket server
const wss = new WebSocketServer({port: SERVER_PORT}); // the webSocket server
var connections = new Array;          // list of connections to the server
const Readline = SerialPort.parsers.Readline;

wss.on('connection', handleConnection);
const myPort = new SerialPort("COM3", {
    baudRate: 115200,
});
myPort.on('open', showPortOpen);
myPort.on('close', showPortClose);
myPort.on('error', showError);

const parser = myPort.pipe(new Readline('\r\n'))
console.log('parser setup');
parser.on('data', function(data) {
    console.log('data received: ', data);
});

function handleConnection(client) {
    console.log("New Connection"); // you have a new client
    connections.push(client); // add this client to the connections array

    client.on('message', sendToSerial); // when a client sends a message,

    client.on('close', function() { // when a client closes its connection
        console.log("connection closed"); // print it out
        var position = connections.indexOf(client); // get the client's position in the array
        connections.splice(position, 1); // and delete it from the array
    });
}

function sendToSerial(data) {
    console.log("sending to serial: " + data);
    myPort.write(data, 'hex');
}

// This function broadcasts messages to all webSocket clients
function broadcast(data) {
    console.log(data);
    for (myConnection in connections) {  // iterate over the array of connections
        connections[myConnection].send(JSON.stringify(data)); // send the data to each connection
    }
}

function showPortOpen() {
   console.log('port open. Data rate: ' + myPort.baudRate);
}

function readSerialData(data) {
   // if there are webSocket connections, send the serial data
   // to all of them:
   if (connections.length > 0) {
     broadcast(data);
   }
}

function showPortClose() {
   console.log('port closed.');
}

function showError(error) {
   console.log('Serial port error: ' + error);
}

我收到了消息，但它们被拆分了，我想将整个消息发送给客户。我试图定义解析器，然后将其传递给管道。我试图在SerialPort构造函数中设置解析器，更改了分隔符，但没有结果。 我认为我的错误与解析器有关。

在这里您可以看到它不返回console.log

这是我使用的结果

myPort.on('data', function(data) {
    console.log('data received: ', data);
});

这个想法是在每个命令之后获取完整的消息并将其发送给客户端。

Answer 1

使用SerialPort中的内置readline api：

const SerialPort = require('serialport');// include the library
const WebSocketServer = require('ws').Server;
const SERVER_PORT = 7000;               // port number for the webSocket server
const wss = new WebSocketServer({port: SERVER_PORT}); // the webSocket server
var connections = new Array;          // list of connections to the server
const Readline = SerialPort.parsers.Readline;

wss.on('connection', handleConnection);

const myPort = new SerialPort('COM3', {
  baudRate: 115200,
  parser: SerialPort.parsers.readline('\r\n')
});

myPort.on('open', showPortOpen);
myPort.on('close', showPortClose);
myPort.on('error', showError);

myPort.on('data', data => readSerialData(data.toString());


// ...

function broadcast(data) {
    console.log(data);
    for (myConnection in connections) {
        connections[myConnection].send(JSON.stringify(data));
    }
}

// ...

function readSerialData(data) {
   // if there are webSocket connections, send the serial data
   // to all of them:
   if (connections.length > 0) {
     broadcast(data);
   }
}

// ...

Answer 2

该消息再次被拆分。因此，我希望整个消息都可以通过十六进制代码进行解码。问题是否来自解析器？