I'm currently with problems while trying to read a .txt file with ElectronJS.
I've start the test using the electron-quick-start repository (running Electron v8.2.1), don't know if it's something with it.
But let's get into it.
my index.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';" />
<title>Hello World!</title>
</head>
<body>
<input type="button" id="btn-readfile" value="Select a file">
<script>
const fs = require('fs')
const {
dialog
} = require('electron').remote
document.getElementById('btn-readfile').addEventListener('click', () => {
dialog.showOpenDialog((fileNames) => {
if (fileNames === undefined) {
console.log("No files were selected")
return
}
fs.readFile(fileNames[0], 'utf-8', (err, data) => {
if (err) {
return
}
console.log("The content is: ")
console.log(data)
})
})
}, false)
</script>
</body>
</html>
I'm able to click the button and select the file from the windows, but nothing happens on my console... Followed this tutorial, and It works. What am I doing wrong?
You should be writing your script inside the renderer.js file which is included in the bottom of the body as <script src="./renderer.js"></script>. I did some modifications to your code in order to make it work:
Make sure this nodeIntegration: true is in your webPreferences in main.js
Your renderer.js file would then contain:
const fs = require('fs')
const {dialog} = require('electron').remote
document.getElementById('btn-readfile').addEventListener('click', () => {
dialog.showOpenDialog({
properties: ['openFile']
}).then((data) => {
console.log(data)
if(data){
fs.readFile( data.filePaths[0], 'utf-8', (err, data) => {
if (err)
return
console.log("The content is: ")
console.log(data)
})
}
});
}, false);
Related
I have been trying to build an app for file managing and different stuff for work. One of the feautures is to open links in windows file explorer, but I am not able to do it. These are the files isolated from the rest of the app code:
index.html:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<meta
http-equiv="Content-Security-Policy"
content="default-src 'self'; script-src 'self'"
/>
<meta
http-equiv="X-Content-Security-Policy"
content="default-src 'self'; script-src 'self'"
/>
<title>Hello from Electron renderer!</title>
</head>
<body>
<h1>Hello from Electron renderer!</h1>
<p>👋</p>
<p id="info"></p>
<div>
<button id="open-file-manager">View Demo</button>
</div>
</body>
<script src="./renderer.js"></script>
</html>
main:
const { app, BrowserWindow } = require('electron');
const path = require('path');
const createWindow = () => {
const win = new BrowserWindow({
width: 800,
height: 600,
webPreferences: {
preload: path.join(__dirname, 'preload.js'),
},
});
win.loadFile('index.html');
};
app.whenReady().then(() => {
createWindow();
app.on('activate', () => {
if (BrowserWindow.getAllWindows().length === 0) {
createWindow();
}
});
});
app.on('window-all-closed', () => {
if (process.platform !== 'darwin') {
app.quit();
}
});
preload:
const { contextBridge } = require('electron');
const { shell } = require('electron');
contextBridge.exposeInMainWorld('bridge', {
electron: () => process.versions.electron,
buttonClick: (link) => shell.openPath(link)
});
renderer:
const information = document.getElementById('info');
information.innerText = `Electron (v${bridge.electron()})`;
const fileManagerBtn = document.getElementById('open-file-manager');
fileManagerBtn.addEventListener('click', (event) => {
bridge.buttonClick('C:/Users')
});
Error when clicking the button once the app has been launched:
Uncaught Error: Cannot read properties of undefined (reading 'openPath')
at HTMLButtonElement.<anonymous> (renderer.js:7:10)
I tried with ContextIsolation false and it worked with little modifaction on renderer so I must be missing something. Please help me in this, I have tried to search for an answer but I am not able to find it.
I finally caught what was happening to my app when I reread the electron documentation. It seems that "shell" cannot be used in "sandboxed" scripts and guess what, since electron v20.0.0 the preload script is a sandboxed script.
Main process can load shell commands so with IPC methods I was able to launch file explorer without deactivating ContextIsolation.
I am building my first electron application and I am running into a JS error I am not sure how to fix. I have managed to setup the IPC for a basic password manager application. The use-case is simple:
I click an HTML button and the frontend connects to the backend and delivers a keyword from which to build a password.
Password is generated.
Upon completion, the password is returned to the frontend to be displayed via HTML in a header tag.
Here is an example of the expected behavior with the input string dog:
keyword --> dog
generated password --> dog-jdls4ksls
The issue I am seeing is that instead of printing the generated password, I am seeing:
[object Object]-jdls4ksls
My best guess is that, since I am using async/await, I am printing the promise memory object instead of the returned value. I do not know, however, how I would block to wait for completion. The code in question providing this output is the last line of render.js, which was called from the HTML body.
Any help would be appreciated!
For context, I am primarily a backend developer, with plenty of python and C/C++/C# experience. My goal is to rebuild a C#/.NET GUI application into an electron app.
Here is all my code.
main.js
const {app, BrowserWindow, ipcMain} = require("electron")
const path = require("path")
function generatePassword(keyword) {
console.log(keyword)
return keyword + '-' + Math.random().toString(36).substring(2,12)
}
function createWindow () {
const win = new BrowserWindow({
width: 800,
height: 600,
resizable: false,
webPreferences: {
preload: path.join(__dirname, 'preload.js')
}
})
win.loadFile('html/passwordGen.html')
}
app.whenReady().then(() => {
ipcMain.handle("generatePassword", generatePassword)
// console.log(generatePassword('test string')) // works
createWindow()
}).catch(error => {
console.log(error) // log error to console
app.quit() // quit the app
})
preload.js
const { contextBridge, ipcRenderer } = require('electron')
contextBridge.exposeInMainWorld('main', {
genPW: (keyword) => ipcRenderer.invoke("geåneratePassword", keyword)
})
render.js
async function testClick () {
const pw_root = document.getElementById("keyword")
const pw_label = document.querySelector("#password")
pw_label.innerText = await window.main.genPW(pw_root.value)
}
passwordGen.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Password Generator</title>
<link rel="stylesheet" href="../css/style.css">
<script src="../render.js"></script>
</head>
<body>
<h1>Password Generator</h1>
<input type="text" id="keyword" placeholder="Please enter a keyword...">
<button id="btn" onclick="testClick()">Generate Password</button>
<h1 id="password"></h1>
</body>
</html>
Edit:
Here is the code that worked. The accepted solution worked with the exception that I needed to either 1) keep the async/await on the generatePassword() or 2) convert it to .then() format as recommended in another solution.
main.js
const {app, BrowserWindow, ipcMain} = require("electron")
const path = require("path")
function generatePassword(keyword) {
console.log(keyword)
return keyword + '-' + Math.random().toString(36).substring(2,12)
}
function createWindow () {
const win = new BrowserWindow({
width: 800,
height: 600,
resizable: false,
webPreferences: {
preload: path.join(__dirname, 'preload.js')
}
})
win.loadFile('html/passwordGen.html')
}
app.whenReady().then(() => {
// ipcMain.handle("generatePassword", generatePassword)
// console.log(generatePassword('stink')) // works
ipcMain.handle('generatePassword', (_event, keyword) => {
console.log(keyword); // Testing
return generatePassword(keyword);
});
createWindow()
}).catch(error => {
console.log(error) // log error to console
app.quit() // quit the app
})
preload.js
const { contextBridge, ipcRenderer } = require('electron')
contextBridge.exposeInMainWorld('main', {
genPW: (keyword) => {
return ipcRenderer.invoke("generatePassword", keyword)
}
})
render.js
async function testClick () {
const pw_root = document.getElementById("keyword")
const pw_label = document.querySelector("#password")
pw_label.innerText = await window.main.genPW(pw_root.value)
// window.main.genPW(pw_root.value).then(res => {pw_label.innerText = res})
// ^^^ works as well if async/await removed
}
You were really close. Using Elctron's invoke method is the correct approach.
Within your main.js file, Electron's IPC handle signature contains the channel and listener arguments. In
your code you are calling your generatePassword() function in place of the listener argument. Instead, it should
be (event, ...args). In your specific case (event, keyword).
See ipcMain.handle(channel, listener)
for more information.
Additionally, within your preload.js script, all you need to do is add a return statement in front of your ipcRenderer.invoke method.
Finally, there is no need to use async on your testClick() function. Electron's invoke handles all of this.
main.js (main process)
const electronApp = require('electron').app;
const electronBrowserWindow = require('electron').BrowserWindow;
const electronIpcMain = require('electron').ipcMain;
const nodePath = require('path');
// Prevent garbage collection
let window;
function createWindow() {
window = new electronBrowserWindow({
x: 0,
y: 0,
width: 800,
height: 600,
resizable: false,
show: false,
webPreferences: {
nodeIntegration: false,
contextIsolation: true,
preload: nodePath.join(__dirname, 'preload.js')
}
});
window.loadFile('index.html')
.then(() => { window.show(); });
return window;
}
electronApp.on('ready', () => {
window = createWindow();
});
electronApp.on('window-all-closed', () => {
if (process.platform !== 'darwin') {
electronApp.quit();
}
});
electronApp.on('activate', () => {
if (electronBrowserWindow.getAllWindows().length === 0) {
createWindow();
}
});
// ---
function generatePassword(keyword) {
console.log(keyword)
return keyword + '-' + Math.random().toString(36).substring(2,12)
}
electronIpcMain.handle('generatePassword', (event, keyword) => {
console.log(keyword); // Testing
return generatePassword(keyword);
});
preload.js (main process)
const contextBridge = require('electron').contextBridge;
const ipcRenderer = require('electron').ipcRenderer;
contextBridge.exposeInMainWorld(
'main', {
genPW: (keyword) => {
return ipcRenderer.invoke('generatePassword', keyword);
}
});
For sake of simplicity, I have included your render.js script within <script> tags below the closing </body> tag.
index.html (render process)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Emergency</title>
<meta http-equiv="Content-Security-Policy" content="script-src 'self' 'unsafe-inline';"/>
</head>
<body>
<div>
<label for="password">Password:</label>
<input type="text" id="password">
<input type="button" id="submit" value="Submit">
</div>
<div>
<label for="generated-password">Generated Password:</label>
<input type="text" id="generated-password" disabled>
</div>
</body>
<script>
document.getElementById('submit').addEventListener('click', () => {
window.main.genPW(document.getElementById('password').value)
.then((generatedPassword) => {
document.getElementById('generated-password').value = generatedPassword;
})
})
</script>
</html>
I dont think you can use async function as event listener, you need to use regular (not async) function here.
function testClick() {
const pw_root = document.getElementById("keyword")
const pw_label = document.querySelector("#password")
window.main.genPW(pw_root.value).then(res => {pw_label.innerText = res})
}
also, you have typo here: invoke("geåneratePassword")
Try using double await as in
await (await callToBackend)
I have a very basic html file (using electron);
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title> File Uploader </title>
<link rel="stylesheet" href="style.css">
<script defer src="render.js"></script>
</head>
<body>
<h1>Drive File Uploader</h1>
<input type="file" id="myFile" name="myFile">
<button onclick="FileUploadPing()">Upload your file</button>
</body>
</html>
and an event listener named render.js;
const ipcRenderer = require("electron").ipcRenderer;
const FileUploadPing = () => {
var input = document.getElementById("myFile").value
if (input) {
ipcRenderer.send("FileUploadPing",inputVal);
}else{console.log("no path value")}
};
ipcRenderer.on("FileRecievePing", (event, data) => {
alert(data)
});
But when I click submit, document.getElementById("myFile").value returns undefined
how can I pull that value?
This is an interesting issue that confronts many people using Electron. One could either use (via Electron) the native OS dialog.showOpenDialog([browserWindow, ]options) dialog or the html <input type="file"> tag.
To circumvent the need to manage the is prefixed with C:\fakepath\ issue, it is often better to use the native approach. After all, that is what Electron is best at.
Let me show you how to quickly set up a html button that when clicked, will open the native file selector dialog, and when a path is selected, return the path to the render thread for display.
In the below code, we will be using a preload.js script configured to communicate (using IPC) between the main thread and render thread(s). Context Isolation will describe this in more detail.
First off, let's code the main.js file which will include the creation of the native file dialog.
main.js (main thread)
const electronApp = require('electron').app;
const electronBrowserWindow = require('electron').BrowserWindow;
const electronDialog = require('electron').dialog;
const electronIpcMain = require('electron').ipcMain;
const nodePath = require("path");
// Prevent garbage collection
let window;
function createWindow() {
const window = new electronBrowserWindow({
x: 0,
y: 0,
width: 1000,
height: 700,
show: false,
webPreferences: {
nodeIntegration: false,
contextIsolation: true,
preload: nodePath.join(__dirname, 'preload.js')
}
});
window.loadFile('index.html')
.then(() => { window.show(); })
return window;
}
electronApp.on('ready', () => {
window = createWindow();
});
electronApp.on('window-all-closed', () => {
if (process.platform !== 'darwin') {
electronApp.quit();
}
});
electronApp.on('activate', () => {
if (electronBrowserWindow.getAllWindows().length === 0) {
createWindow();
}
});
// Open the file dialog
electronIpcMain.on('message:openDialog', (event) => {
let options = {
title: 'Select File',
properties: ['openFile']
};
electronDialog.showOpenDialog(window, options)
.then((result) => {
if (result.canceled) {
console.log('User cancelled file dialog.');
return;
}
event.reply('message:dialogPath', result.filePaths[0]);
})
.catch((error) => { console.error(error); });
})
Now, let's create the index.html file, which for the sake of simplicity, also includes the Javascript within the <script> tags.
NB: Instead of deferring your script in the <head>, you can include it just before the closing <html> tag. Placing it here effectively performs the same thing as defer in the <head> <script> tag.
index.html (render thread)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Drive File Uploader</title>
</head>
<body>
<div>Drive File Uploader</div>
<hr>
<label for="path">Path: </label>
<input type="text" id="path" name="path">
<input type="button" id="open-dialog" name="open-dialog" value="...">
<input type="button" id="upload" value="Upload">
</body>
<script>
// Let's declare it as it is used more than once
let filePath = document.getElementById('path');
// Event listeners
document.getElementById('open-dialog').addEventListener('click', () => { window.ipcRender.send('message:openDialog'); });
document.getElementById('upload').addEventListener('click', () => { console.log(filePath.value); });
// IPC message from the main thread
window.ipcRender.receive('message:dialogPath', (path) => { filePath.value = path; })
</script>
</html>
Finally, let's add the preload.js script to allow the main thread and render thread(s) to safely communicate with each other.
Note: This is where we define our whitelisted channel names.
preload.js (main thread)
const contextBridge = require('electron').contextBridge;
const ipcRenderer = require('electron').ipcRenderer;
// White-listed channels.
const ipc = {
'render': {
// From render to main.
'send': [
'message:openDialog'
],
// From main to render.
'receive': [
'message:dialogPath'
],
// From render to main and back again.
'sendReceive': []
}
};
// Exposed protected methods in the render process.
contextBridge.exposeInMainWorld(
// Allowed 'ipcRenderer' methods.
'ipcRender', {
// From render to main.
send: (channel, args) => {
let validChannels = ipc.render.send;
if (validChannels.includes(channel)) {
ipcRenderer.send(channel, args);
}
},
// From main to render.
receive: (channel, listener) => {
let validChannels = ipc.render.receive;
if (validChannels.includes(channel)) {
// Deliberately strip event as it includes `sender`.
ipcRenderer.on(channel, (event, ...args) => listener(...args));
}
},
// From render to main and back again.
invoke: (channel, args) => {
let validChannels = ipc.render.sendReceive;
if (validChannels.includes(channel)) {
return ipcRenderer.invoke(channel, args);
}
}
}
);
Hopefully, the above outlines how simple it can be to use (via Electron) the native dialog boxes. The benefit being they have OS specific functionality and feel.
I dont know what I did different, but when I tried this it suddenly worked.
main.js;
const { app, BrowserWindow, ipcMain } = require("electron");
let win = null;
const createWindow = () => {
win = new BrowserWindow({
width: 800,
height: 600,
resizable: true,
webPreferences: {
nodeIntegration: true,
contextIsolation: false,
enableRemoteModule: true,
nativeWindowOpen: true,
},
});
win.loadFile("index.html");
};
app.whenReady().then(createWindow);
render.js;
const ipcRenderer = require("electron").ipcRenderer;
const {uploadFileToCloud} = require("C:/Users/efeba/desktop/pythonAndJS/ITGSProject/app.js")
const FileUploadPing = () => {
var name = document.getElementById("myFile").value
name = name.replace("C:\\fakepath\\","")
console.log(name)
var path = document.getElementById("myFile").files[0].path
path = path.replace(name,"")
path = path.replaceAll("\\", "/") // beautify the string
console.log(path)
if (path) {
uploadFileToCloud(name, path)
alert("File Uploaded")
}else{console.log("no path value")}
};
//file uploads but content is empty
//I suspect pulling the libraries in renderer has some problems, will
//try to make it by sending a ping to main.js
index.html;
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title> File Uploader </title>
<link rel="stylesheet" href="style.css">
<script defer src="render.js"></script>
</head>
<body>
<h1>Drive File Uploader</h1>
<input type="file" id="myFile" name="myFile">
<button onclick="FileUploadPing()">Upload your file</button>
</body>
</html>
Hope I could help
in android logcat, I expect android webview raise js err with typescript source, following is my sample code
testdraft.ts
window.onerror = (message, file, line, column, err) => {
if (err !== undefined) {
(window as any).mapStackTrace(err.stack, (mappedStack:any) => {
console.log(mappedStack)
})
}
}
var m = () => {
throw new Error("pr")
}
m()
testdraft.js.map
{"version":3,"file":"testdraft.js","sourceRoot":"","sources":["testdraft.ts"],"names":[],"mappings":";AAAA,MAAM,CAAC,OAAO,GAAG,CAAC,OAAO,EAAE,IAAI,EAAE,IAAI,EAAE,MAAM,EAAE,GAAG,EAAE,EAAE;IAClD,IAAI,GAAG,KAAK,SAAS,EAAE;QAClB,MAAc,CAAC,aAAa,CAAC,GAAG,CAAC,KAAK,EAAE,CAAC,WAAe,EAAE,EAAE;YACzD,OAAO,CAAC,GAAG,CAAC,WAAW,CAAC,CAAA;QAC5B,CAAC,CAAC,CAAA;KACL;AACL,CAAC,CAAA;AAED,IAAI,CAAC,GAAG,GAAG,EAAE;IACT,MAAM,IAAI,KAAK,CAAC,IAAI,CAAC,CAAA;AACzB,CAAC,CAAA;AACD,CAAC,EAAE,CAAA"}
how to parse testdraft.js.map?
I know chrome://inspect can debug android webview, but I expect android logcat also raise backtrace with typescript source for app production stage analysis
I find "stacktrace-js" can convert bundle stacktrace to source stacktrace(or you can make own source-map parser)
see following:
testdraft.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
</head>
<body>
<!--<script src="../node_modules/sourcemapped-stacktrace/dist/sourcemapped-stacktrace.js"></script>-->
<script src="../node_modules/stacktrace-js/dist/stacktrace.js"></script>
<script src="./testdraft.js"></script>
</body>
</html>
testdraft.ts
window.onerror = (message, file, line, column, err) => {
if (err !== undefined) {
(window as any).StackTrace.fromError(err).then((err: any) => {
console.log(err.join("\n"))
}).catch(() => {
})
}
}
var m = () => {
throw new Error("pr")
}
m()
use tsc compile testdraft.ts to testdraft.js + testdraft.js.map and run testdraft.html
so the android webview solution is, use webview in pageStated run js load stacktrace-js and following code:
window.onerror = (message, file, line, column, err) => {
if (err !== undefined) {
(window as any).StackTrace.fromError(err).then((err: any) => {
console.log(err.join("\n"))
}).catch(() => {
})
}
}
or maybe better way, don't use webview api run above code, use webpack prepend above code in bundle.js first
I'm building an App (Electron based) where I need to get an information from a third party website before the main window is created, but I'm a little bit confused about security measures. I'm using axios to do the HTTP request inside the main process because it is promise based and I can create the window after the website is fetched. My concerns are:
Enabling nodeIntegration is not good when messing with the renderer process because of cross-site-scripting attack. Should I include all nodejs modules in a preload.js like the following, for example.
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="Content-Security-Policy" content="script-src 'self';">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Viewer</title>
</head>
<body>
<div id="box">
<form id='fo'>
<input type="text" id="num">
<button type="button" id="bttn">Random</button>
</form>
</div>
<script src="renderer.js"></script>
</body>
</html>
main.js
const electron = require('electron');
const cheerio = require('cheerio');
const axios = require('axios').default;
const path = require('path');
const {app, BrowserWindow, ipcMain, Menu, MenuItem,session} = electron;
let win;
let url = 'sampletext';
function createWindow() {
win = new BrowserWindow({
width: 400,
height: 250,
webPreferences:{
nodeIntegration: false,
contextIsolation: true,
preload: path.join(app.getAppPath(), 'preload.js')
},
show: false,
});
win.loadFile('index.html');
win.once('ready-to-show', () =>{
win.show();
});
win.on('closed', () =>{
win = null;
});
}
app.whenReady().then(getRequest().then(res => {
const $ = cheerio.load(res);
if($('infoNeeded')){
random = get_numbers($('infoNeeded').attr('href'));
}
createWindow();
}));
app.on('window-all-closed', () =>{
app.quit();
});
function getRequest() {
return axios.get(url).then(res => res.data).catch(err => console.log(err));
}
preload.js
//Instead of using getRequest() on main.js use this file
const electron = require('electron');
const remote = require('electron').remote;
const cheerio = require('cheerio');
const axios = require('axios').default;
let url = 'sampletext';
//So I can use it in renderer.js
window.getReq = function () {
return axios.get(url).then(res => res.data).catch(err => console.log(err));
}
window.parseInfo = function (data) {
const $ = cheerio.load(data);
if($('infoNeeded')){
return random = get_numbers($('infoNeeded').attr('href'));
}
return;
}
//Preload first request
window.getReq().then(doStuffHere);
renderer.js
let info;
//Keep updating the info
setInterval( () =>{
window.getReq().then(data => {
info = window.parseInfo(data);
});
}, 10000);
1) Is it ok to do nodejs require inside main process? If not, what's the secure way of doing it?
2) May I make HTTP requests inside main process? If yes, should I send a CSP header when doing so?
3) Instead of doing the request inside the main.js, should I use "webPreferences: preload" property and make the first HTTP request inside preload.js (Just like the above example) ? (I need to get the info before sending it to renderer.js)
I've already read https://www.electronjs.org/docs/tutorial/security, but I couldn't grasp their teaching. If you could provide an answer for how and when to use preload.js and CSP header I'll be very grateful.
Yes it is ok to use node.js require in the main process(use any library with error handling, cause it may crash the app)
You can make an HTTP request from the main process
You can use Preload.js if you need the code execution result in the renderer process.(You can also use the ipc)