Epson js SDK 无法使用多台打印机

Question

简介
我们正在开发这个基于 javascript 的 Web 应用程序，它应该使用 epson javascript sdk 打印收据。

现在我们已经有了这个 poc，可以将多台打印机添加到应用程序中，并且可以为每台打印机打印收据。

问题是收据只能是最后添加的打印机的打印机。

进一步调查告诉我们，sdk 只使用最后添加（连接）的打印机。这可以在以下图片中看到。

1. 在第一个图像中有 2 台打印机设置。注意不同的 IP 地址。
2. 在第二张图片中，我们记录了打印时使用的 EpsonPrinter 实例。请注意，IP 地址显然是第一台打印机。
3. 在第三张图片中，我们跟踪网络。注意实际使用的ip地址（忽略错误）。

我们创建了自己的 EpsonPrinter 类，可以在 here 或下方找到。

EpsonPrinter

export default class EpsonPrinter {
  name = null
  ipAddress = null
  port = null
  deviceId = null
  crypto = false
  buffer = false
  eposdev = null
  printer = null
  intervalID = null
  restry = 0

  constructor (props) {
    const {
      name = 'Epson printer',
      ipAddress,
      port = 8008,
      deviceId = 'local_printer',
      crypto = false,
      buffer = false
    } = props
    this.name = name
    this.ipAddress = ipAddress
    this.port = port
    this.deviceId = deviceId
    this.crypto = crypto
    this.buffer = buffer

    this.eposdev = new window.epson.ePOSDevice()
    this.eposdev.onreconnecting = this.onReconnecting
    this.eposdev.onreconnect = this.onReconnect
    this.eposdev.ondisconnect = this.onDisconnect

    this.connect()
  }

  onReconnecting = () => {
    this.consoleLog('reconnecting')
  }
  onReconnect = () => {
    this.consoleLog('reconnect')
  }

  onDisconnect = () => {
    this.consoleLog('disconnect')

    if (this.intervalID === null ){
      this.intervalID = setInterval(() => this.reconnect(), 5000)
    }
  }

  connect = () => {
    this.consoleLog('connect')

    this.eposdev.ondisconnect = null
    this.eposdev.disconnect()

    this.eposdev.connect(this.ipAddress, this.port, this.connectCallback)
  }

  reconnect = () => {
    this.consoleLog('(Re)connect')

    this.eposdev.connect(this.ipAddress, this.port, this.connectCallback)
  }

  connectCallback = (data) => {
    clearInterval(this.intervalID)
    this.intervalID = null
    this.eposdev.ondisconnect = this.onDisconnect

    if (data === 'OK' || data === 'SSL_CONNECT_OK') {
      this.createDevice()
    } else {
      setTimeout(() => this.reconnect(), 5000)
    }
  }

  createDevice = () => {
    console.log('create device, try: ' + this.restry)

    const options = {
      crypto: this.crypto,
      buffer: this.buffer
    }

    this.eposdev.createDevice(this.deviceId, this.eposdev.DEVICE_TYPE_PRINTER, options, this.createDeviceCallback)
  }

  createDeviceCallback = (deviceObj, code) => {
    this.restry++

    if (code === 'OK') {
      this.printer = deviceObj
      this.printer.onreceive = this.onReceive
    } else if (code === 'DEVICE_IN_USE') {
      if (this.restry < 5) {
        setTimeout(() => this.createDevice(), 3000)
      }
    }
  }

  onReceive = (response) => {
    this.consoleLog('on receive: ', response)
    let message = `Print ${this.name} ${response.success ? 'success' : 'failute'}\n`
    message += `Code: ${response.code}\n`
    message += `Status: \n`

    if (response.status === this.printer.ASB_NO_RESPONSE) { message += ' No printer response\n' }
    if (response.status === this.printer.ASB_PRINT_SUCCESS) { message += ' Print complete\n' }
    if (response.status === this.printer.ASB_DRAWER_KICK) { message += ' Status of the drawer kick number 3 connector pin = "H"\n' }
    if (response.status === this.printer.ASB_OFF_LINE)  {   message += ' Offline status\n' }
    if (response.status === this.printer.ASB_COVER_OPEN)    {   message += ' Cover is open\n' }
    if (response.status === this.printer.ASB_PAPER_FEED) {  message += ' Paper feed switch is feeding paper\n' }
    if (response.status === this.printer.ASB_WAIT_ON_LINE) {    message += '  Waiting for online recovery\n' }
    if (response.status === this.printer.ASB_PANEL_SWITCH) {    message += ' Panel switch is ON\n' }
    if (response.status === this.printer.ASB_MECHANICAL_ERR) {  message += ' Mechanical error generated\n' }
    if (response.status === this.printer.ASB_AUTOCUTTER_ERR) {  message += ' Auto cutter error generated\n' }
    if (response.status === this.printer.ASB_UNRECOVER_ERR) {   message += ' Unrecoverable error generated\n' }
    if (response.status === this.printer.ASB_AUTORECOVER_ERR) { message += ' Auto recovery error generated\n' }
    if (response.status === this.printer.ASB_RECEIPT_NEAR_END) {    message += ' No paper in the roll paper near end detector\n' }
    if (response.status === this.printer.ASB_RECEIPT_END) { message += ' No paper in the roll paper end detector\n' }
    if (response.status === this.printer.ASB_SPOOLER_IS_STOPPED) {  message += ' Stop the spooler\n' }

    if (!response.success) {
      alert(message)
      // TODO: error message?
    } else {
      // TODO: success -> remove from queue
    }
  }

  printReceipt = () => {
    this.consoleLog(`Print receipt, `, this)
    try {
      if (!this.printer) {
        throw `No printer created for ${this.name}`
      }

      this.printer.addPulse(this.printer.DRAWER_1, this.printer.PULSE_100)

      this.printer.addText(`Printed from: ${this.name}\n`)

      this.printer.send()
    } catch (err) {
      let message = `Print ${this.name} failure\n`
      message += `Error: ${err}`

      alert(message)
    }
  }

  consoleLog = (...rest) => {
    console.log(`${this.name}: `, ...rest)
  }
}

Poc
可以在 here 找到完整的工作 poc。

爱普生javascript sdk
2.9.0

有没有人有使用 epson sdk 的经验？它应该能够同时支持多个连接吗？请告知使用。

Answer 1

适用于寻找使用此 SDK 处理多台打印机的方法的用户。我们想出了以下解决方法：

我们创建了一个单独的“打印机应用程序”，负责处理一个打印机连接并将其在线托管。然后，我们将此打印机应用程序“加载”到需要使用 iframe 进行多个连接的应用程序中。应用程序和打印机应用程序之间的通信是通过 window.PostMessage API 完成的，例如，使用正确的打印机连接初始化打印机并提供必须打印的数据。

这需要一些努力，但它是我们能想到的处理多个连接的最稳定的解决方案。

如果有人想出更好的方法，请告诉我！

您可以查看我们的打印机应用程序here 以获取灵感（检查该应用程序，因为它并没有显示太多像那样访问它）。

Answer 2

为了使用您的 EpsonPrinter 类，我还在您的类之后添加了 myPrinters 类：

class myPrinters {
    printers = null;
    cantidad = 0;

    constructor() {
        console.log("Creo la coleccion de printers");
        this.printers = [];
    }

    inicializarConeccionImpresora(idImpresora, ip, puerto, _deviceId) {
        let ipAddress = ip;
        let port = puerto;
        let deviceId = _deviceId;
        console.log("Agrego una impresora");
        let myPrinter = new EpsonPrinter(ipAddress);
        myPrinter.port = port;
        myPrinter.deviceId = deviceId;
        myPrinter.id = idImpresora;
        console.log('Id impresora antes de connect es: ' + idImpresora);
        myPrinter.connect();
        this.printers[this.cantidad] = myPrinter;
        this.cantidad ++;   
    }

    imprimirPruebaJS(idImpresora) {
        let printer = null;
        let printerTemp = null
        for(var i = 0; i < this.printers.length; i++) {
            printerTemp = this.printers[i];
            if (printerTemp.id == idImpresora) {
                printer = printerTemp.printer;
            }
        }

        if (printer == null) {
            console.log("La impresora no esta iniciada en clase myPrinters");
            return;
        }

        printer.addText('Hola mundo texto normal\n');
        printer.addFeed();
        printer.addCut(printer.CUT_FEED);
    }
}

以这种方式调用 myPrinters 类：

myEpsonPrinters = new myPrinters();

myEpsonPrinters.inicializarConeccionImpresora(1, '192.168.0.51', 8008, 'local_printer');
myEpsonPrinters.inicializarConeccionImpresora(2, '192.168.0.52', 8008, 'local_printer');

myEpsonPrinters.imprimirPruebaJS(1)
or
myEpsonPrinters.imprimirPruebaJS(2)

测试它并告诉我。 娟

Answer 3

只需创建多个打印对象就可以了

this.eposdev = [];

let printersCnt = 3;

let self = this;

for(let i=1 ; i <= printersCnt ; i++){

    this.eposdev[i] = new window.epson.ePOSDevice()

    this.eposdev[i].onreconnecting = function (){
        this.consoleLog('reConnecting')
    }

    this.eposdev[i].onreconnect =  function (){
       this.consoleLog('onReconnect')
    }

    this.eposdev[i].ondisconnect = function (){
        this.consoleLog('onDisconnect')
    }    
} 


function connect(printerKey) => {

    this.consoleLog('connect')

    this.eposdev.ondisconnect = null
    this.eposdev.disconnect()

    this.eposdev.connect(self.ipAddress[printerKey], self.port[printerKey], function(){

        clearInterval(self.intervalID)

        self.intervalID = null
        self.eposdev[i].ondisconnect = self.ondisconnect

        if (data === 'OK' || data === 'SSL_CONNECT_OK') {

            console.log('create device, try: ' + self.restry)

            const options = {
              crypto: self.crypto,
              buffer: self.buffer
            }

            self.eposdev[printerKey].createDevice(self.deviceId, self.eposdev[printerKey].DEVICE_TYPE_PRINTER, options, function(deviceObj, code){
                this.restry++

                if (code === 'OK') {
                  self.printer[printerKey] = deviceObj
                  self.printer.onreceive = function(){
                      console.log("onreceive");
                  }
                } else if (code === 'DEVICE_IN_USE') {
                  if (self.restry < 5) {
                    setTimeout(() => self.createDevice(printerKey), 3000)
                  }
                })
            }


        } else {
          setTimeout(() => self.reconnect(printerKey), 5000)
        }

    })
} 

Answer 4

Epson 表示，在 2.12.0 版本中，您可以添加多台打印机。