通过Node.js和Socket.io来实现手机的远程控制

jopen 9年前

通过Node.js和Socket.io来实现手机的远程控制

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用手机来实现远程控制是不是很酷？你不需要去写一个APP应用来实现这种功能-现在的手机浏览器已经支出了web socket技术，这提供了很多的可能。
这篇文章我们将用Node.js和Socket.io来实现手机控制PC的效果。

我们不必到处寻找基于HTML5的这种应用库。我们将使用Reveal.js-它来处理幻灯片动画效果，并支持键盘和触摸事件。

我们不必自己来实现远程控制的接口，我们将实现手机和电脑的同步。这样不仅能控制进度，也能同步的显示在你的手机上。

实现思路

技术上很简单。Reveal.js让当前的幻灯片序号在URL的hash上(e.g.http://example.com/#/1).我们将这个hash发送到所有连接的设备上，
对应的将会根据这个hash来自动的显示响应幻灯片。这样的话，别人可以方便的直接通过url来直接访问到显示的页面，所有我们需要输入一个验证码
在连接之前进行验证。

要说的是Reveal.js已经有一套API,我们可以直接调用来同步。但是hash变化的技术很简单，我们可以直接来实现。

通过Node.js和Socket.io来实现手机的远程控制

运行

你可以本地运行示例，或者部署到能提供node.js环境的服务器上。本地运行更简单些，但是必须本地有node.js并执行npm install.

运行本地代码

  • 下载示例代码
  • 确保本地已经安装node.js。如果没有，请安装
  • 解压刚才下载的代码包
  • 打开终端进入相应的文件夹
  • 运行npm install来安装依赖包
  • 运行node app.js来启动应用
  • PC端在浏览器打开http://localhost:8080，并输入连接码(默认是kittens)
  • 在手机端浏览器打开http://<your computer’s local ip address>，并输入连接码
  • 请享受

代码

思路说完，让我们来看看代码。这主要涉及2个js文件-app.js服务端控制，script.js浏览器端。你可以运行这个应用在Node.js 1.10+或者io.js.

后端，我们用到了express和Socket.io.它主要用来响应socket.io的事件监听。用express.static来让public下的文件可以访问到。
public/index.html文件保护显示的代码。express.static将会让它自动显示，所以我们不需要/来路由。

app.js 

// This is the server-side file of our mobile remote controller app.  // It initializes socket.io and a new express instance.  // Start it by running 'node app.js' from your terminal.      // Creating an express server    var express = require('express'),      app = express();    // This is needed if the app is run on heroku and other cloud providers:    var port = process.env.PORT || 8080;    // Initialize a new socket.io object. It is bound to  // the express app, which allows them to coexist.    var io = require('socket.io').listen(app.listen(port));      // App Configuration    // Make the files in the public folder available to the world  app.use(express.static(__dirname + '/public'));      // This is a secret key that prevents others from opening your presentation  // and controlling it. Change it to something that only you know.    var secret = 'kittens';    // Initialize a new socket.io application    var presentation = io.on('connection', function (socket) {        // A new client has come online. Check the secret key and      // emit a "granted" or "denied" message.        socket.on('load', function(data){            socket.emit('access', {              access: (data.key === secret ? "granted" : "denied")          });        });        // Clients send the 'slide-changed' message whenever they navigate to a new slide.        socket.on('slide-changed', function(data){            // Check the secret key again            if(data.key === secret) {                // Tell all connected clients to navigate to the new slide                presentation.emit('navigate', {                  hash: data.hash              });          }      });  });    console.log('Your presentation is running on http://localhost:' + port);

下面是前端的js文件，将监听hashchange事件，并发送socket.io消息到服务器端。

public/assets/js/script.js 

$(function() {        // Apply a CSS filter with our blur class (see our assets/css/styles.css)        var blurredElements = $('.homebanner, div.reveal').addClass('blur');        // Initialize the Reveal.js library with the default config options      // See more here https://github.com/hakimel/reveal.js#configuration        Reveal.initialize({          history: true        // Every slide will change the URL      });        // Connect to the socket        var socket = io();        // Variable initialization        var form = $('form.login'),          secretTextBox = form.find('input[type=text]');        var key = "", animationTimeout;        // When the page is loaded it asks you for a key and sends it to the server        form.submit(function(e){            e.preventDefault();            key = secretTextBox.val().trim();            // If there is a key, send it to the server-side          // through the socket.io channel with a 'load' event.            if(key.length) {              socket.emit('load', {                  key: key              });          }        });        // The server will either grant or deny access, depending on the secret key        socket.on('access', function(data){            // Check if we have "granted" access.          // If we do, we can continue with the presentation.            if(data.access === "granted") {                // Unblur everything              blurredElements.removeClass('blurred');                form.hide();                var ignore = false;                $(window).on('hashchange', function(){                    // Notify other clients that we have navigated to a new slide                  // by sending the "slide-changed" message to socket.io                    if(ignore){                      // You will learn more about "ignore" in a bit                      return;                  }                    var hash = window.location.hash;                    socket.emit('slide-changed', {                      hash: hash,                      key: key                  });              });                socket.on('navigate', function(data){                    // Another device has changed its slide. Change it in this browser, too:                    window.location.hash = data.hash;                    // The "ignore" variable stops the hash change from                  // triggering our hashchange handler above and sending                  // us into a never-ending cycle.                    ignore = true;                    setInterval(function () {                      ignore = false;                  },100);                });            }          else {                // Wrong secret key                clearTimeout(animationTimeout);                // Addding the "animation" class triggers the CSS keyframe              // animation that shakes the text input.                secretTextBox.addClass('denied animation');                animationTimeout = setTimeout(function(){                  secretTextBox.removeClass('animation');              }, 1000);                form.show();          }        });    });

现在是幻灯片放映时间

手机远程访问控制已经可以了。希望你能从中得到有趣的体验。

参考：

http://tutorialzine.com/2015/02/smartphone-remote-control-for-presentations/
https://github.com/hakimel/reveal.js/wiki/Example-Presentations

来自：http://ljinkai.github.io/2015/06/19/phone-control-slide/