通过浏览器显示范围内的蓝牙设备 [英] Showing bluetooth devices in range via browser

问题描述

一个简单的想法。我想在通过AJAX调用的网络浏览器中显示计算机范围内的蓝牙设备（通过蓝牙 - 串口 - 端口NodeJS包使用蓝牙加密狗）。

A simple idea. I would like to show bluetooth devices in range of the computer (using a bluetooth dongle via bluetooth-serial-port NodeJS package) in the web browser served up upon call over AJAX.

我遇到的问题是，使用以下脚本，我无法连续扫描设备并同时提供网站。你能解释一下这个工作流程以及为什么/什么是纠正这个问题的好方向？

The issue I am having is that with the following script, I can't continiously scan for devices and serve up web sites at the same time. Could you explain the workflow in this and why/what would be a good direction to rectify the issue?

var http = require("http"),
    url = require("url"),
    path = require("path"),
    fs = require("fs"),
    port = process.argv[2] || 8888,
    btSerial = new (require('bluetooth-serial-port')).BluetoothSerialPort();

btSerial.inquire();

// Get the devices
var devices = [];

btSerial.on('found', function(address, name) {
  if(typeof devices[address] === 'undefined'){
    devices.push({'address': address,'name': name});
    console.log("Device Found: "+address+" which is named: "+name);
  }
});

// Keep searching
btSerial.on('finished', function() {
  console.log("Done searching");
  console.log(devices);
  //btSerial.inquire();
});


http.createServer(function(request, response) {

  var uri = url.parse(request.url).pathname,
    filename = path.join(process.cwd(), uri);

  if (uri == '/devices') {
    response.writeHead(200, {"Content-Type": "application/json"});
    response.write(JSON.stringify(devices));
    response.end();
    return;
  }

  fs.exists(filename, function(exists) {
    if(!exists) {
      response.writeHead(404, {"Content-Type": "text/plain"});
      response.write("404 Not Found\n");
      response.end();
      return;
    }

    if (fs.statSync(filename).isDirectory()) filename += 'public/index.html';

    fs.readFile(filename, "binary", function(err, file) {
      if(err) {        
        response.writeHead(500, {"Content-Type": "text/plain"});
        response.write(err + "\n");
        response.end();
        return;
      }

      response.writeHead(200);
      response.write(file, "binary");
      response.end();
    });
  });
}).listen(parseInt(port, 10));

console.log("Static file server running at\n  => http://localhost:" + port + "/\nCTRL + C to shutdown");

推荐答案

解决方案比预期简单得多。

The solution was much simpler than expected.

首先，我创建了一个蓝牙扫描程序服务（永远运行），打开一个套接字并在每个设备的查找位置向服务器服务提供更新的结果。我将setTimeout函数设置为1s（1000ms），否则结果将不会传递给侦听服务器。

First I created a bluetooth scanner service (running with forever) that opens a socket and delivers updated results to the server service at the find of each device. I set the setTimeout function to 1s (1000ms) otherwise the results would not be delivered to the listening server.

var port = 9838,
    devices = {},
    socket = require('socket.io-client')('http://localhost:'+port);
    btSerial = new (require('bluetooth-serial-port')).BluetoothSerialPort();

var onFinishedFoundDevice = function(message){
    // Add new device to object array
    if(typeof message.address !== 'undefined' && typeof message.name !== 'undefined') 
        devices[message.address] = {'address': message.address,'name': message.name};

    console.log("Sent new device", message);
};

var sendMessage = function(type, message, callback){
    this.message = message;
    socket.emit(type, message);

    if(callback)
        callback(message);
};


var findBluetooths = function () {
  // Scan for BT devices in range
  btSerial.on('found', function(address, name) {
    if(typeof devices[address] === 'undefined'){
      var message = {'address': address, 'name': name}; // prepare message
      sendMessage('add-device', message, onFinishedFoundDevice); // actually send message to server
      console.log("Device Found: "+address+" which is named: "+name);
    }
  });

  // Keep searching
  btSerial.on('finished', function() {
    console.log("Received Finished... cont'd");
    setTimeout(function(){btSerial.inquire();}, 1000);
  });

  // Scan for devices
  console.log("Begin scanning");
  btSerial.inquire();
}

// Do the magic
findBluetooths();

我创建了一个服务器服务（也是永远运行），它启用了HTTP服务器以及socket.io事件的监听器。它接收来自蓝牙扫描仪以及index.html页面的事件。

Than I created a server service (running in forever as well) that enables HTTP server as well as a listener for socket.io events. It takes in events from the bluetooth scanner as well as the index.html page.

var app = require('http').createServer(handler), 
    io = require('socket.io')(app),
    fs = require('fs'),
    port = 9838,
    devices = [];

app.listen(port);

function handler (req, res) {
  fs.readFile(__dirname + '/public/index.html',
  function (err, data) {
    if (err) {
      res.writeHead(500);
      return res.end('Error loading index.html');
    }

    res.writeHead(200);
    res.end(data);
  });
}

io.on('connection', function (socket) {
  socket.emit('devices', devices);

  socket.on('add-device', function(device) {
        devices.push({'address': device.address,'name': device.name});
        socket.broadcast.emit('device-added', device); // send device to browsers
        console.log("Device Found: "+device.address+" which is named: "+device.name);
    });

  socket.on('get-devices', function(payload){
n  });

});

最后，我创建了一个public / index.html文件来显示扫描结果以及发出请求来自服务器的更多信息。

Finally I created a public/index.html file to display the scanning results as well as issue requests for more information from the server.

<!DOCTYPE html>
<html>
    <head>
        <title>Bluetooth Scanner</title>
        <script src="http://code.jquery.com/jquery-2.1.1.min.js"></script>
        <script src="/socket.io/socket.io.js"></script>
        <script>
            var port = 9838;
            var hostname = window.location.hostname;
            var socket = io(hostname+':'+port);

            socket.on('welcome', function (message) {
                console.log(message);
            });

            socket.on('device-added', function (device) {
                $("#no-devices").hide();

                $('<li>', {
                    html: "Device named "+device.name+" with MAC "+ device.address+" is online."
                }).appendTo('#devices');
            });

            socket.on('devices', function(devices){
                if(devices.length > 0) $("#no-devices").hide();

                $.each(devices, function(key, device){
                    $('<li>', {
                        html: "Device named <b>"+device.name+"</b> with MAC <b>"+ device.address+"</b> is online."
                    }).appendTo('#devices');
                });

            });

        </script>
    </head>
    <body>
        <div>
            <span id="no-devices">No devices yet...</span>
            <ul id="devices"></ul>
        </div>
    </body>
</html>

谢谢大家的帮助。它缺乏真正使其可用的必要功能，但它是我的项目的良好开端

Thank you all for the help. It lacks necessary functionality to really make it usable but it is a good start for my project

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