If you want to try Electron, check out this pit crawl summary

preface

The Web side can do a lot of things, but when it comes to operating systems, it can be a bit overwhelming. Some time ago when developing a Web system, encountered a similar situation. We need to get some information about the computer’s operating system, such as the MAC address. Our Web system is completely on the server, through the browser to run, but through the Web side can not directly achieve the effect we want.

Problems are left to people to solve. After discussion among colleagues, because the system itself is not complex, and to carry out rapid development. It was decided to use Electron + the original Web system page to solve problems involving operating system information.

This article summarizes some of the problems AND solutions I have encountered with Electron.

What is Electron?

Build cross-platform desktop applications using JavaScript, HTML, and CSS – this is the introduction to Electron

Electron is an open source framework developed by GitHub. It allows desktop GUI application development using Node.js (as the back end) and Chromium (as the front end). Electron has been used for front-end and back-end development by several open source Web applications, including GitHub’s Atom and Microsoft’s Visual Studio Code. – zhihu

Electron puts a shell on the Node.js environment for Web projects, enabling us to call the rich API of Node.js. This way we can write desktop applications in JavaScript, extending a lot of things we can’t do on the Web.

How do YOU build Electron?

Building Electron is as simple as looking directly at official documentation or using an existing wheel. Basically, they fall into two broad categories: templates and command-line tools. These two ways have their own advantages, the specific choice of which way to according to their actual situation. For me, because the project I’m going to do already has web pages, these templates are basically not applicable. In order to catch up with the schedule, I will directly refer to the official website for introduction — build your first -electron- application, plus the original code to build the project.

Here are some common build templates and command-line tools

The template

Electron -react-boilerplate: electron + react
electron-vue: electron + vue
.

Command line tool

Build your first Electron app: official website tutorial
Electron forge: A sophisticated tool for building modern electron applications
.

A case in point

The following is a basic Electron project that the rest of the code expands on.

npm install --save-dev electron
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The general structure

├─ ├─ download.txt └─ ├─ download.txtCopy the code

package.json

{
  "name": "demo"."version": "1.0.0"."description": "electornDemo"."main": "main.js"."scripts": {
    "start": "electron ."
  },
  "author": "xmanlin"."license": "MIT"."devDependencies": {
    "electron": "^ 9.0.0"}}Copy the code

main.js

const {app, BrowserWindow} = require('electron')

app.on('ready'.function createWindow () {
    // Multiple renderers can be created
    let win = new BrowserWindow({
        width: 800.height: 600,
    })
    
    win.show()

    // Web pages in the renderer process can load local files
    win.loadFile('index.html')


    // Remember to clear this variable after the page is closed to prevent memory leaks
    win.on('closed'.function () {
        win = null})})// Close the main process after all the pages are closed
app.on('window-all-closed', () => {
    app.quit()
})
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index.html


      
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>demo</title>
</head>
<body>
    <div>An electron project</div>
    <script>
    
    </script>
</body>
</html>
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What are main processes and renderers?

In Electron, the concept of main process and render process is very important. For details, see main process and Render process on the Electron website.

The main process

runpackage.jsonIn themainThe script process is the main process.
A electron application has one and only one main process.
The main process can perform guI-related native API operations.

Rendering process

Electron uses Chromium to present web pages, so Chromium’s multi-process architecture is also used.
Each Web page runs in its own rendering process.
useBrowserWindowClass starts a renderer process and runs the instance in that process when aBrowserWindowAfter the instance is destroyed, the corresponding rendering process is terminated.
Native resources cannot be called in the renderer process, but the renderer process also contains node.js environment, so you can introduce Node.js module, with node.js support, the page and the operating system can do some low-level interaction.

How does the Node.js API get called in the rendering process?

In Electron5.0, renderers cannot call the Node.js API by default.

Main process (main.js)

let win = new BrowserWindow({
    width: 800.height: 600.webPreferences: {
        nodeIntegration: true.// Set to true to invoke Node.js in the renderer}})Copy the code

How to open developer tools?

Electron uses Chromium, but opening developer tools isn’t like a browser, like F12 by default on Windows.

There are two ways to open the developer tool in Electron:

The first is to set it in the main process, and when it starts the project, the renderer opens developer tools by default

 win.webContents.openDevTools();
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The second option is to select View -> Toggle Developer Tools from the menu bar of the render process window. (Or just follow the shortcut keys above)

Does the electron console print garble?

We may encounter Chinese garbled characters in the Windows console. When we input CHCP in the Windows console, we can see the current character encoding. The common gb2312 value is 936, and the UTF8 value is 65001. This can be resolved by simply setting package.json.

"start": "chcp 65001 && electron ."
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How does the main process communicate with the renderer process?

The main process and the renderer process can communicate with each other through the ipcRenderer and ipcMain modules.

The main process actively sends a message to the renderer

Main process (main.js)

// The main process sends a message to the renderer process, 'did-finish-load': emits an event when the navigation is complete, and the onload event completes
win.webContents.on('did-finish-load', () => {
    win.webContents.send('msg'.'Message coming from autonomous process')})Copy the code

Render process (index.html)

<script>
    const {ipcRenderer} = require('electron')
    ipcRenderer.on('msg', (event, message) => {
        console.log(message) // The message comes from the autonomous process
    })
</script>
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The renderer actively sends a message to the main process

Render process (index.html)

Const {ipcRenderer} = require('electron') ipcrenderer. send('indexMsg',' message from renderer ')Copy the code

Main process (main.js)

const {ipcMain} = require('electron')
ipcMain.on('indexMsg',(event,msg) => {
    console.log(msg) // The message comes from the renderer
})
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How do renderers communicate with each other?

There are many ways for renderers to communicate with each other, some of which are listed below:

Use the global share attribute

/ / main process
global.sharedObject = {
  user: ' '
}

Render process 1
const {remote} = require('electron')
remote.getGlobal('sharedObject').user = 'xmanlin'

// Render process 2
const {remote} = require('electron')
console.log(remote.getGlobal('sharedObject').user) //xmanlin
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ipcRenderer.sendTo()

Here are the arguments to ipcrenderer.sendto ()

ipcRenderer.sendTo(webContentsId, channel, [, arg1][, arg2][, ...] ) ipcRenderer.sendTo(windowId,'ping'.'someThing') //webContentsId : Number //channel : String //... args : any[]Copy the code

The specific use

Main process (main.js)

// Create a new renderer
let win2 =  new BrowserWindow({
    width: 800.height: 600,})// Set a unique ID for the renderer process
win2.id = 2
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Render process 1

<script>
    const {ipcRenderer} = require('electron')
    // Send a message to the renderer with id 2
    ipcRenderer.sendTo(2.'msg1'.'Message from Renderer 1')
</script>
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Render Process 2

<script>
    const {ipcRenderer} = require('electron')
    ipcRenderer.on('msg1', (event, message) => {
        console.log(message) // Message from renderer 1
    })
</script>
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Use the main process as a message relay

/ / main process
ipcMain.on('msg1', (event, message) => {
  yourWindow.webContents.send('msg2', message);
}

Render process 1
ipcRenderer.send('msg1'.'Message from Renderer 1')

// Render process 2
ipcRenderer.on('msg2', (event, message) => {
    console.log(message)  // Message from renderer 1})Copy the code

How are projects packaged?

Packing is also an essential step. Here are two mature packing tools: electron packager and electron Builder. These two tools mainly configure it.

electron-packager

We can use the electron packager to package our existing electron application as an exe executable.

Install first

npm install electron-packager --save-dev
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After installing the electron packager, configure the basic command. The following is the basic command format in the official document:

electron-packager <sourcedir> <appname> --platform=<platform> --arch=<arch> [optional flags...]
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Briefly introduce the meaning of each parameter:

Sourcedir: indicates the path of the project
Appname: Application name (packaged file name)
Platform: Determines which platform you want to build the application on (Windows, Mac, or Linux)
- platform=win32On behalf of the Windows
- platform=darwinOn behalf of the Mac
- platform=linuxOn behalf of the Linux
Arch: Deciding whether to use x86 or X64 or both architectures
Optional options: Optional options

Here is an example for your reference

package.json

"scripts": { "build32": "Electron packager./ appDemo --platform=win32 --arch=ia32 --out=./app --app-version=1.0.0 --overwrite --icon=./favicon.ico", "build64": "Electron packager./ appDemo --platform=win32 --arch=x64 --out=./app --app-version=1.0.0 --overwrite --icon=./favicon.ico" }Copy the code

These are all packaged for Windows, build32 packaged for 32-bit, build64 packaged for 64-bit. In addition to basic parameters, the meanings of other parameters are as follows:

–out indicates the directory of the generated file after packaging
–app-version Specifies the version number of the generated package file
— Overwrite Deletes the original package file and generates a new package file
–icon Indicates the icon of the package file

electron-builder

The electric-Builder can be packaged not only as an exe executable but also as an installable program, and has more features than the electric-Packager.

The official website favors YARN for installation

yarn add electron-builder --dev
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Of course NPM is also possible

npm install electron-builder --save-dev
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Then we can configure

"scripts": {
  "pack": "electron-builder --dir"."dist": "electron-builder"
},
 "build": {
   "productName": "appDemo".// App name in Chinese
   "appId": "appDemoId"./ / app id
   "directories": { // Package the output folder
     "buildResources": "resources"."output": "dist/"
   }
   "files": [ // The source file remains after packaging
     "dist/electron"."node_modules/"."package.json"]."mac": { // MAC package configuration
     "target": "dmg"."icon": "icon.ico"
   },
   "win": { // Windows package configuration
     "target": "nsis"."icon": "icon.ico"
   },
   "dmg": { // DMG file package configuration
     "artifactName": "appDemo.dmg"."contents": [{"type": "link"."path": "/Applications"."x": 410."y": 150
       },
       {
         "type": "file"."x": 130."y": 150}},"nsis": { // nsis file package configuration
     "oneClick": false."allowToChangeInstallationDirectory": true.// Allows you to change the installation directory
     "allowElevation": true.// Allow request promotion. If false, the user must restart setup with the promoted permissions.
     "installerIcon": "./build/icons/aaa.ico".// Install icon
     "uninstallerIcon": "./build/icons/bbb.ico".// Uninstall the icon
     "installerHeaderIcon": "./build/icons/aaa.ico".// Install header icon
     "createDesktopShortcut": true.// Create a desktop icon
     "createStartMenuShortcut": true.// Create start menu icon
     "shortcutName": "xxxx".// Icon name
     "include": "build/script/installer.nsh".// The included custom NSIS script is quite useful for building a strict installation process.}},Copy the code

Parameters can also be specified when using the electron builder package

-- MAC, -m, -O, -- macOS MacOS package -- Linux, -l Linux package --win, -w, -- Windows Windows package -- MWL for macOS, Windows and Linux package --x64 x64 (64-- Ia32 Ia32 (32Bit installation package)Copy the code

For all parameters, see Command Line Interface (CLI).

About NSIS, you can also know the following packing method: electron packing process electron-packager + NSIS

How do I set Windows to Max and full screen by default?

Default maximization

// Main process (main.js)
let win = new BrowserWindow({show: false})
win.maximize()
win.show()
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The default full screen

// Main process (main.js)
let win = new BrowserWindow({fullscreen: true})
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How to customize the menu bar?

You can refer directly to this article – use the Electron custom menu to write in more detail, or you can refer directly to the official documentation. Of course, we can also hide the built-in menu bar and then call the write Electron API to write a menu bar. VSCode, for example, does this. Open VSCode and find the switch developer tool in help. You may find a new world.

How do I obtain the MAC address of the operating system?

This is a call to node.js API to get the MAC address of the system.

var os=require("os");
// Obtain the MAC address
var mac = ' '
var networkInterfaces=os.networkInterfaces();
for(var i in networkInterfaces){
    for(var j in networkInterfaces[i]){
        if(networkInterfaces[i][j]["family"= = ="IPv4" && networkInterfaces[i][j]["mac"]! = ="00:00:00:00:00:00" && networkInterfaces[i][j]["address"]! = ="127.0.0.1"){
            mac = networkInterfaces[i][j]["mac"]}}}Copy the code

reference

www.electronjs.org/docs

Blog.csdn.net/weixin_4276…

www.jianshu.com/p/62c45eddb…

Blog.csdn.net/qq_34803821…

Segmentfault.com/a/119000001…

Juejin. Cn/post / 684490…

The last

This article is the problems I have encountered and the solutions I have found in learning and applying Electron so far. I hope it will be helpful to you. If there are any shortcomings or mistakes, please point them out

If you want to try Electron, check out this pit crawl summary

preface

What is Electron?

How do YOU build Electron?

The template

Command line tool

A case in point

What are main processes and renderers?

The main process

Rendering process

How does the Node.js API get called in the rendering process?

How to open developer tools?

Does the electron console print garble?

How does the main process communicate with the renderer process?

The main process actively sends a message to the renderer

The renderer actively sends a message to the main process

How do renderers communicate with each other?

Use the global share attribute

ipcRenderer.sendTo()

Use the main process as a message relay

How are projects packaged?

electron-packager

electron-builder

How do I set Windows to Max and full screen by default?

How to customize the menu bar?

How do I obtain the MAC address of the operating system?

reference

The last

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