串行 API 中 navigator.serial 和 SerialPort 上的函数是否未实现？

Question

I am trying to connect to the serial port from a web page. I found the Serial API which can support that.

 var Serial = {}; (function() { 'use strict'; /* * */ Serial.debug = true; /* * */ // Serial.device; /* * */ Serial.log = function(message) { if(Serial.debug) { let pre; if(!document.querySelector('pre')) { pre = document.createElement('pre'); document.body.appendChild(pre); } pre = document.querySelector('pre'); pre.innerHTML += `\\n${message}`; } } /* * */ Serial.request = function() { const requestOptions = { // Filter on devices with the Arduino USB vendor ID. filters: [{ vendorId: 0x0403 }], }; // Request an Arduino from the user. console.log(navigator); console.log(navigator.serial); const port = navigator.serial.requestPort(requestOptions); // Open and begin reading. port.open({ baudrate: 19200 }); const reader = port.in.getReader(); while (true) { const {done, data} = reader.read(); if (done) break; console.log(data); } } /* * */ Serial.port = { /* * */ device:{}, /* * */ connect:function() { let loop = () => { this.device.transferIn(5, 64).then(result => { Serial.log(result); loop(); }, error => { WebUSB.log(error); }); } console.log(this.device); return this.device.open( {baudrate: 19200 }) .then(() => this.device.selectConfiguration(1)) .then(() => this.device.claimInterface(1)) .then(() => this.device.controlTransferOut({requestType: 'class', recipient: 'interface', request: 0x22, value: 0x01, index: 0x02})) .then(() => {loop}) .then( result => { Serial.log('successfull'); } ) .catch( error => { Serial.log(error); } ); }, /* * */ send:function() { let d = new Date(); let h = d.getHours(); let m = d.getMinutes(); let s = d.getSeconds(); if(h < 10){h = `0${h}`}; if(m < 10){m = `0${m}`}; if(s < 10){s = `0${s}`}; let data = `show time ${h}${s % 2 == 1 ? ':' : ' '}${m}${s % 2 == 0 ? ':' : ' '}${s}`; console.log(data); let textEncoder = new TextEncoder(); WebUSB.port.device.transferOut(4, textEncoder.encode(data)); }, /* * */ disconnect:function() { console.log(Serial.port.device) Serial.port.device.close() .then( result => { Serial.log('closed'); document.querySelectorAll('button')[1].parentNode.removeChild(document.querySelectorAll('button')[1]); } ) .catch( error => { Serial.log(error); } );; } } })(); /* * */ window.addEventListener('DOMContentLoaded', connect => { let button = document.createElement('button'); button.innerHTML = 'Connect a USB Device'; button.addEventListener('click', Serial.request); document.body.appendChild(button); }, true);

But the navigator.serial.requestPort() call is failing; I find that the navigator.serial is undefined. I'm pretty sure the serial port is connected to my computer. Are functions on navigator.serial and SerialPort in Serial API unimplemented? My chrome version is 74.0.3729.131. My system is Ubuntu 16.04

Answer 1

The Serial API is not yet completely implemented in Chrome. I see that you have already found the issue in the Chromium bug tracker for the implementation. Updates on implementation progress will be posted there. It is currently in the "started" state, not "fixed".

Answer 2

Posting @Benjamin 's answer for the sake of clarity. Serial port connection's are still an "experimental" feature in Chrome early 2020. You have to turn on the following option:

chrome://flags/#enable-experimental-web-platform-features

Just copy paste that line in the Chrome address bar and enable it.