I'm creating an Electron app for my own purpose. My problem is when I'm using node functions inside my HTML page it throws an error of:
'require()' is not defined.
Is there any way to use Node functionalities in all my HTML pages? If it is possible please give me an example of how to do this or provide a link. Here are the variables I'm trying to use in my HTML page:
var app = require('electron').remote;
var dialog = app.dialog;
var fs = require('fs');
and these are the values I'm using in all my HTML windows within Electron.
As of version 5, the default for nodeIntegration changed from true to false.
You can enable it when creating the Browser Window:
app.on('ready', () => {
mainWindow = new BrowserWindow({
webPreferences: {
nodeIntegration: true,
contextIsolation: false,
}
});
});
Edit 2022
I've published a larger post on the history of Electron and it's security that provides additional context on the changes that affect how security was approached in different framework versions (and what's the best approach to take).
Original answer
I hope this answer gets some attention, because a large majority of answers here leave large security holes in your electron app. In fact this answer is essentially what you should be doing to use require() in your electron apps. (There is just a new electron API that makes it a little bit cleaner in v7).
I wrote a detailed explanation/solution in github using the most current electron apis of how you can require() something, but I'll explain briefly here why you should follow an approach using a preload script, contextBridge and ipc.
The problem
Electron apps are great because we get to use node, but this power is a double-edged sword. If we are not careful, we give someone access to node through our app, and with node a bad actor can corrupt your machine or delete your operating system files (among other things, I imagine).
As brought up by #raddevus in a comment, this is necessary when loading remote content. If your electron app is entirely offline/local, then you are probably okay simply turning on nodeIntegration:true. I still would, however, opt to keep nodeIntegration:false to act as a safeguard for accidental/malicious users using your app, and prevent any possible malware that might ever get installed on your machine from interacting with your electron app and using the nodeIntegration:true attack vector (incredibly rare, but could happen)!
What does the problem look like
This problem manifests when you (any one of the below):
Have nodeIntegration:true enabled
Use the remote module
All of these problems give uninterrupted access to node from your renderer process. If your renderer process is ever hijacked, you can consider all is lost.
What our solution is
The solution is to not give the renderer direct access to node (ie. require()), but to give our electron main process access to require, and anytime our renderer process needs to use require, marshal a request to the main process.
The way this works in the latest versions (7+) of Electron is on the renderer side we set up ipcRenderer bindings, and on the main side we set up ipcMain bindings. In the ipcMain bindings we set up listener methods that use modules we require(). This is fine and well because our main process can require all it wants.
We use the contextBridge to pass the ipcRenderer bindings to our app code (to use), and so when our app needs to use the required modules in main, it sends a message via IPC (inter-process-communication) and the main process runs some code, and we then send a message back with our result.
Roughly, here's what you want to do.
main.js
const {
app,
BrowserWindow,
ipcMain
} = require("electron");
const path = require("path");
const fs = require("fs");
// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let win;
async function createWindow() {
// Create the browser window.
win = new BrowserWindow({
width: 800,
height: 600,
webPreferences: {
nodeIntegration: false, // is default value after Electron v5
contextIsolation: true, // protect against prototype pollution
enableRemoteModule: false, // turn off remote
preload: path.join(__dirname, "preload.js") // use a preload script
}
});
// Load app
win.loadFile(path.join(__dirname, "dist/index.html"));
// rest of code..
}
app.on("ready", createWindow);
ipcMain.on("toMain", (event, args) => {
fs.readFile("path/to/file", (error, data) => {
// Do something with file contents
// Send result back to renderer process
win.webContents.send("fromMain", responseObj);
});
});
preload.js
const {
contextBridge,
ipcRenderer
} = require("electron");
// Expose protected methods that allow the renderer process to use
// the ipcRenderer without exposing the entire object
contextBridge.exposeInMainWorld(
"api", {
send: (channel, data) => {
// whitelist channels
let validChannels = ["toMain"];
if (validChannels.includes(channel)) {
ipcRenderer.send(channel, data);
}
},
receive: (channel, func) => {
let validChannels = ["fromMain"];
if (validChannels.includes(channel)) {
// Deliberately strip event as it includes `sender`
ipcRenderer.on(channel, (event, ...args) => func(...args));
}
}
}
);
index.html
<!doctype html>
<html lang="en-US">
<head>
<meta charset="utf-8"/>
<title>Title</title>
</head>
<body>
<script>
window.api.receive("fromMain", (data) => {
console.log(`Received ${data} from main process`);
});
window.api.send("toMain", "some data");
</script>
</body>
</html>
Disclaimer
I'm the author of secure-electron-template, a secure template to build electron apps. I care about this topic, and have been working on this for a few weeks (at this point in time).
For security reasons, you should keep nodeIntegration: false and use a preload script to expose just what you need from Node/Electron API to the renderer process (view) via window variable. From the Electron docs:
Preload scripts continue to have access to require and other Node.js features
Example
main.js
const mainWindow = new BrowserWindow({
webPreferences: {
preload: path.join(app.getAppPath(), 'preload.js')
}
})
preload.js
const { remote } = require('electron');
let currWindow = remote.BrowserWindow.getFocusedWindow();
window.closeCurrentWindow = function(){
currWindow.close();
}
renderer.js
let closebtn = document.getElementById('closebtn');
closebtn.addEventListener('click', (e) => {
e.preventDefault();
window.closeCurrentWindow();
});
First off, #Sathiraumesh solution leaves your electron application with huge security issue. Imagine that your app is adding some extra features to messenger.com, for example toolbar's icon will change or blink when you've have unread message. So in your main.js file, you create new BrowserWindow like so (notice I intentionally misspelled messenger.com):
app.on('ready', () => {
const mainWindow = new BrowserWindow({
webPreferences: {
nodeIntegration: true
}
});
mainWindow.loadURL(`https://messengre.com`);
});
What if messengre.com is a malicious website, that wants to harm your computer. If you set nodeIntegration: true this site has access to your local file system and can execute this:
require('child_process').exec('rm -r ~/');
And your home directory is gone.
Solution
Expose only what you need, instead of everything. This is achived by preloading javascript code with require statements.
// main.js
app.on('ready', () => {
const mainWindow = new BrowserWindow({
webPreferences: {
preload: `${__dirname}/preload.js`
}
});
mainWindow.loadURL(`https://messengre.com`);
});
// preload.js
window.ipcRenderer = require('electron').ipcRenderer;
// index.html
<script>
window.ipcRenderer.send('channel', data);
</script>
Now awful messengre.com cannot delete your entire file system.
It looks like Electron's security evolved like this (source).
Electron 1 nodeIntegration defaults to true
Renderer has full access to Node API -- huge security risks if Renderer loads remote code.
Electron 5 nodeIntegration defaults to false
When set to false, a preload script is used to expose specific API to Renderer. (The preload script always has access to Node APIs regardless of the value of nodeIntegration)
//preload.js
window.api = {
deleteFile: f => require('fs').unlink(f)
}
Electron 5 contextIsolation defaults to true (actually still defaults to false in Electron 11)
This causes preload script to run in a separate context. You can no longer do window.api = .... You now have to do:
//preload.js
const { contextBridge } = require('electron')
contextBridge.exposeInMainWorld('api', {
deleteFile: f => require('fs').unlink(f)
})
Electron 6 require()ing node builtins in sandboxed renderers no longer implicitly loads the remote version
If Renderer has sandbox set to true, you have to do:
//preload.js
const { contextBridge, remote } = require('electron')
contextBridge.exposeInMainWorld('api', {
deleteFile: f => remote.require('fs').unlink(f)
})
Electron 10 enableRemoteModule default to false (remote module deprecated in Electron 12)
The remote module is used when you need to access Node APIs from a sandboxed Renderer (as in above example); or when you need to access Electron APIs that are available only to the Main process (such as dialog, menu). Without remote, you'll need to write explicit IPC handlers like follows.
//preload.js
const { contextBridge, ipcRenderer } = require('electron')
contextBridge.exposeInMainWorld('api', {
displayMessage: text => ipcRenderer.invoke("displayMessage", text)
})
//main.js
const { ipcMain, dialog } = require('electron')
ipcMain.handle("displayMessage", text => dialog.showMessageBox(text))
Electron 10 deprecate nodeIntegration flag (removed in Electron 12)
Recommendation
Always set {nodeIntegration: false, contextIsolation: true, enableRemoteModule: false}.
For max security, set {sandbox: true}. Your preload script will have to use IPC to call the Main process to do everything.
If sandbox is false, your preload script can access Node API directly, as in require('fs').readFile. You're secure as long as you don't this:
//bad
contextBridge.exposeInMainWorld('api', {
readFile: require('fs').readFile
})
Are you using nodeIntegration: false while BrowserWindow initialization? If so, set it to true (defaults value is true).
And include your external scripts in the HTML like this (not as <script> src="./index.js" </script>):
<script>
require('./index.js')
</script>
All I wanted to do was to require a js file in my html page because of the tutorial I was following. However, I intend to use remote modules so security was paramount. I modified Michael's answer up there so I'm posting, purely for those who spent hours looking for a secure alternative to 'require' like me. If the code is incorrect, feel free to point it out.
main.js
const electron = require('electron');
const app=electron.app;
const BrowserWindow=electron.BrowserWindow;
const ipcMain=electron.ipcMain;
const path=require('path');
const url=require('url');
let win;
function createWindow(){
win=new BrowserWindow({
webPreferences:{
contextIsolation: true,
preload: path.join(__dirname, "preload.js")
}
});
win.loadURL(url.format({
pathname: path.join(__dirname, 'index.html'),
protocol: 'file',
slashes: true
}));
win.on('close', function(){
win=null
});
}
app.on('ready', createWindow);
preload.js
const electron=require('electron');
const contextBridge=electron.contextBridge;
contextBridge.exposeInMainWorld(
"api", {
loadscript(filename){
require(filename);
}
}
);
index.html
<!DOCTYPE html>
<html>
<head>
<title>Hello World App</title>
</head>
<body>
<h1>Hello World</h1>
<button id="btn">Click</button>
</body>
<script>
window.api.loadscript('./index.js');
</script>
</html>
index.js
const btn = document.getElementById('btn');
btn.addEventListener('click', function(){
console.log('button clicked');
});
I am especially curious to know if this still presents a security risk. Thanks.
If you just don't care about any security issues and want to have require being interpreted correctly by JavaScript on the browser window, then have an extra flag on the main.js code:
webPreferences: {
nodeIntegration: true,
nodeIntegrationInWorker: true,
nodeIntegrationInSubFrames: true,
enableRemoteModule: true,
contextIsolation: false //required flag
}
//rest of the code...
You have to enable the nodeIntegration in webPreferences to use it. see below,
const { BrowserWindow } = require('electron')
let win = new BrowserWindow({
webPreferences: {
nodeIntegration: true
}
})
win.show()
There was a breaking api changes in electron 5.0(Announcement on Repository). In recent versions nodeIntegration is by default set to false.
Docs Due to the Node.js integration of Electron, there are some extra symbols inserted into the DOM like module, exports, require. This causes problems for some libraries since they want to insert the symbols with the same names.To solve this, you can turn off node integration in Electron:
But if you want to keep the abilities to use Node.js and Electron APIs, you have to rename the symbols in the page before including other libraries:
<head>
<script>
window.nodeRequire = require;
delete window.require;
delete window.exports;
delete window.module;
</script>
<script type="text/javascript" src="jquery.js"></script>
</head>
For sake of actuality and completeness I am adding my piece of cake. Here is what I find important about this topic. Please keep in mind the date of this post - October 2022, the version of electron is 21.1.1.
There is an article in electron docs called Inter-Process Communication where this topic is described in a very clear way.
The following code is just a copy of the example code on that aforementioned site.
The main.js file:
const {app, BrowserWindow, ipcMain} = require('electron')
const path = require('path')
function createWindow () {
const mainWindow = new BrowserWindow({
webPreferences: {
preload: path.join(__dirname, 'preload.js')
}
})
ipcMain.on('set-title', (event, title) => {
const webContents = event.sender
const win = BrowserWindow.fromWebContents(webContents)
win.setTitle(title)
})
mainWindow.loadFile('index.html')
}
app.whenReady().then(() => {
createWindow()
app.on('activate', function () {
if (BrowserWindow.getAllWindows().length === 0) createWindow()
})
})
app.on('window-all-closed', function () {
if (process.platform !== 'darwin') app.quit()
})
The takeaway:
in webPreferences define only the preload script and leave all those nodeIntegration, nodeIntegrationInWorker, nodeIntegrationInSubFrames, enableRemoteModule, contextIsolation apply the defaults.
The next file is preload.js:
const { contextBridge, ipcRenderer } = require('electron')
contextBridge.exposeInMainWorld('electronAPI', {
setTitle: (title) => ipcRenderer.send('set-title', title)
})
Here the electronAPI object will be injected into the browsers context so there will be a window.electronAPI object which will have a member function called setTitle. Of course you can add whatever other properties there.
The setTitle function only calls ipcRenderer.send which is one end of the Inter-Process Communication brigde or tunnel if you like.
What you send in here falls out on the other end, which is in the main.js file, the ipcMain.on function. Here you register for the set-title event.
The example continues with the index.html file:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<!-- https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP -->
<meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self'">
<title>Hello World!</title>
</head>
<body>
Title: <input id="title"/>
<button id="btn" type="button">Set</button>
<script src="./renderer.js"></script>
</body>
</html>
which loads the renderer.js script:
const setButton = document.getElementById('btn')
const titleInput = document.getElementById('title')
setButton.addEventListener('click', () => {
const title = titleInput.value
window.electronAPI.setTitle(title)
});
and there you can access the window.electronAPI.setTitle function, which you defined in preload.js where it sends the title into ipcRenderer and this title then falls out of ipcMain in main.js fireing an event and causing a function to run which in turn sets the application title.
So once again I want to emphasize to read the documentation. There is more about IPC with exanples. Also read the Context Isolation chapter, it is short and very clear.
Finally, I made it work.Add this code to your HTML document Script Element.
Sorry for the late Reply.I use the below code to do this thing.
window.nodeRequire = require;
delete window.require;
delete window.exports;
delete window.module;
And use nodeRequire instead of using require.
It works Fine.
I am trying to create a quote widget on electron. For renderer process, I created index.js and coded like below
console.log('from renderer');
var request = require('request');
const electron = require('electron');
var url ="https://quotesondesign.com/wp-json/wp/v2/posts/?orderby=rand&_="+rnd;
request(url, function(error, response, body) {
if(error)
{
document.getElementById("quote").innerHTML = 'Unable to fetch the quote plaese check the network connection';
return;
}
let bodyJSON = JSON.parse(body);
console.log(bodyJson);
let randomQuote = bodyJSON[0]["content"]["rendered"];
document.getElementById("quote").innerHTML = randomQuote;
});
And index.html has
<div id="quote">
</div>
<script src="index.js">
// require ('index.js');
</script>
If I use require ('index.js'); in script tag, it doesn't work. So I used src="index.js". Now renderer process works but on console, it shows "Uncaught ReferenceError: require is not defined at index.js:3"
My 1st query is why require ('index.js'); on script tag doesn't work on index.html
and 2nd query is how to fix the Uncaught ReferenceError problem on index.js
My electron version is v8.2.0 and node version is v12.16.1 and dependencies on package.json are as follows:
"dependencies": {
"request": "^2.88.2",
"require": "^2.4.20"
}
Anyone help me please. Thanks in advance.
Since Electron 5, Node integration in the renderer process is disabled by default. To get around that, you need to declare nodeIntegration: true when instantiating your BrowserWindow.
// In the main process.
const { BrowserWindow } = require('electron')
const mainWindow = new BrowserWindow({
width: 800,
height: 600,
webPreferences: {
nodeIntegration: true
}
})
Edit: As of Electron 12, you'll also need to define contextIsolation: false in order to do this, as the default value of the flag has changed.
https://www.electronjs.org/docs/breaking-changes#default-changed-contextisolation-defaults-to-true
The reason why require ('index.js'); doesn't work in the script tag is because require isn't defined for the browser. It is only defined for Node. The reason why you are getting the ReferenceError in index.js is because what <script src="index.js> is actually doing is running the code in index.js in the browser environment. So since it is being run in the browser require isn't defined here also.
I've been trying to convert a small webapp into an electron application. It's working perfectly, except I need to load a bunch of files (.html) into the main DOM. In the webapp, I just used $.get, but how can I do it in electron? I try looking at the DOC but I cannot find an easy way to do that, beside an IPC pipe (and I don't quite get it).
Could anyone point me to the right direction?
Edit
I'll clarify here. I have a main process that start a BrowserWindow
mainWindow = new BrowserWindow({width: 800, height: 600})
and then, in a js file imported via a <script> tag, I want to get load and attach some file inside a dialog:
$('.dialog').load('pages/hello.html', {})
Kind regards
On the Electron side you will have this code starting with the electron library. With ES6 destructuring you can pull the app property off. The app object represents the overall running process on your machine.
const electron = require('electron');
const { app } = electron;
Then you want to add on an event handler:
app.on('ready', () => {
console.log('app is ready');
});
Once you have this running successfully. You have pulled the app property which is the underlying process. You have successfully added your event based function using the app object.
So you then want to create a new browser window to show content to the user, you pull off another property called BrowserWindow, pass it an empty object with your configuration.
const electron = require('electron');
const { app, BrowserWindow } = electron;
app.on('ready', () => {
const mainWindow = new BrowserWindow({width: 800, height: 600});
});
You can then load the HTML document by calling the method loadURL() passing ES6 template string:
const electron = require('electron');
const { app, BrowserWindow } = electron;
app.on('ready', () => {
const mainWindow = new BrowserWindow({width: 800, height: 600});
mainWindow.loadURL(`file://${__dirname}/index.html`);
});
In Electron you can do it with fs.readFile
So :
const fs = require('fs');
const { promisify } = require('util');
const path = require('path');
const readFile = promisify(fs.readFile);
async function loadHTML(html){
const render = await readFile(path.join(__dirname, html), 'utf-8');
const parser = new DOMParser();
const childrenArray = parser.parseFromString(render,'text/html').querySelector('body').childNodes;
const frag = document.createDocumentFragment();
childrenArray.forEach(item => {
frag.appendChild(item);
});
document.body.appendChild(frag);
};
loadHTML('/path/to/my/index.html');
If I don't have a Typo, it should work.
it reads the file as a string so you need to parse this String with the DOMParser.
Load like this:
`file://${path.join(__dirname,"/../../../../../../src/offline.html")}`
Let's try to understand each part:
Reason
file
we will be accessing file protocol, not HTTP directly
__dirname
comes with node integration in electron, everyone should set it to true
path.join
else navigating up won't happen actually, it will be simple string concatenation
why all those nav up?
maybe it's development dependant, for my case I had to log and find that src directory
About that navigating up, I tried on different OS and PC, most of the cases were the same. Except for one exception. Which also had a different config. And I didn't dare to change that, as the config is working.
I have a problem problem in my program using Electron.
First, I was typing require() code in 'main.js'.
const { app, BrowserWindow, globalShortcut, Menu, ipcMain } = require('electron')
Above code does not show an error from console. And I have creating another source file func.js.
I was typing require() code in func.js.
const { ipcRenderer, remote } = require('electron')
But above code shows an error in the console.
So I don't know what is wrong. The ES6 script uses the import () statement, but I do not really know if there was an error in main.js, but I do not know why other files fail.
I got the same error & solved by adding the line bellow in main js file:
from:
win = new BrowserWindow({
})
to:
win = new BrowserWindow({
webPreferences: {nodeIntegration: true},
})
This occurs when you introduce a connecting JS code between html and corresponding Javascript file.
I have seen a lot of questions from people trying to console log from the rendering process, this is NOT my problem I have console.log littering my main code and I don't see anything in my console here is my code.
/* eslint-disable no-undef */
const { app, BrowserWindow, ipcMain } = require('electron');
const path = require('path');
const url = require('url');
/* eslint-enable */
let win;
console.log('console log test');
function createWindow() {
win = new BrowserWindow({
width: 800,
height: 800
});
win.loadURL(url.format({
pathname: path.join(__dirname, 'index.html'),
protocol: 'file:',
slashes: true
}));
win.on('close', () => {
win = null;
});
console.log('console log test');
}
app.on('ready', createWindow);
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') {
app.quit();
}
});
app.on('activate', () => {
if (win == null) {
console.log('console log test');
createWindow();
console.log('console log test');
}
});
I don't see a single log other than the ones produced by electron itself
I've tried throwing errors and those work fine but anything console.* related doesn't work at all, I've tried running it in PowerShell and re-pulling from GitHub, my friend can see the console logs when he pulls the project though so it seems I'm isolated. I've also updated NPM and all modules associated with the project AND I've tried creating a new console and logging to that one but it doesn't seem to show up, am I missing something? I've put hours into this and am ready to give up.
On Windows, if you want to see a console with all your messages from console.log(), you must launch your app with the parameter --enable-logging, for example :
MyApp.exe --enable-logging
I feel your pain. I have this issue on one of my boxes (a Server2012 box). Nothing worked for me until I stumbled across this comment on one of the electron issues threads.
Typically when you install electron you will have a script in your package.json that looks like this.
"scripts": {
"start": "electron .",
}
I changed mine to
"scripts": {
"start": "C:/path/to/project/node_modules/electron-prebuilt/dist/electron.exe .",
}
And I started to get logging from the main electron process in powershell.
Note that if you are using newer versions of electron, you may need to change electron-prebuilt to electron.
How about logging directly into the browser console?
I have found this to be easier for my workflow.
So what I do is to set a listener on the ipcRenderer to the main process and anytime I needed to log a thing from the main, I just emit to the listerner on the renderer.
For instance, in the renderer.js, I set up like so:
pre.ipcRenderer.on("log", (event,log) => {
console.log(log)
});
and in the main, wherever I need to log a piece of code, I just insert this line of code:
window.webContents.send("log", [__dirname]);
My Assumptions with the codes above:
You have set nodeIntegration: false in your webPreference object. This is why codes like __dirname will be unavailable on the renderer process.
As a result of the above, you are using a preloader to load all your required node-specific files.
I defined all of them in my preload.js file and ship them into one giant object which I named window.pre
One of the preloaded modules in the pre object is ipcRenderer. This is why I consumed it as pre.ipcRenderer
All of these is to say that, if you are consuming your nodes directly from the renderer process, you wont need to be bothered by my pre. and if not, now you now why I used it.
Ciao.