How to run Express inside an Electron app

express_in_electron.md

How to run Express inside an Electron app

You can run your Express app very easily inside your Electron app.

All you need to do is to:

• place all the files of your Express app inside a new app folder in your_electron_app\resources\app
• reconfigure the app.js file
• refactor some relative pathes in your Express app

Configure app.js

You should start your Express app before opening a new BrowserWindow and the load a new mainWindow like this:

const express = require('./express'); //your express app

app.on('ready', function() {
  express();
  mainWindow = new BrowserWindow({
    width: 1280,
    height: 720,
    autoHideMenuBar: true,
    useContentSize: true,
    resizable: false,
  });
  mainWindow.loadURL('http://localhost:5000/');
  mainWindow.focus();

});

Refactor pathes

Pathes in Electron don't work the same way they do in your Express app.

You have to make them all from relative to absolute pathes first.

So instead of doing this:

app.set('views', '/client/views');
app.use(express.static(/client/dist/static));

you have to do this:

app.set('views', __dirname + '/client/views');
app.use(express.static(__dirname + '/client/dist/static'));

I am trying to the same thing with NextJs. Instead of exporting the app as static html files, I am spinning up a local server and trying to achieve the same thing what next start does.

But it doesn't work once I bundle my app using electron-builder. Did you guys find anything?

Same here, Express + socket.io + react in my electron app, build doesn't work, but developpment mode is working

For me, the build was failing because one of the devDependency was not getting bundled, so I moved it to the dependencies and it started working.
Just build the app and run locally to see the error.

@dcooney
You can get a port that is available at production time by using the get-port-electron

How do I send the data from express app to main.js? For example, I use express to receive data to PORT 3000 in app.js. Now I send data from external device to PORT 3000 and I want to send that data to main.js. Is there a way to do this?

Yes, you can have a class that extends EventEmitter and just create a single instance of that class. Use this instance everywhere and listen to the event.

The second way: You can import a function into the file which has express Js from main.js which can be called to manipulates the data of main.js.

Yes, you can have a class that extends EventEmitter and just create a single instance of that class. Use this instance everywhere and listen to the event.

The second way: You can import a function into the file which has express Js from main.js which can be called to manipulates the data of main.js.

I will try the EventEmitter. Thank You

Starting express in a forked child process works great when you want to keep the main thread from freezing:

const { fork } = require("child_process");

  let ps;
  //...
  ps = fork(`${__dirname}/../out-tsc/server-app/main.js`, [], {
    cwd: `${__dirname}/../`,
  });

Starting express in a forked child process works great when you want to keep the main thread from freezing:

const { fork } = require("child_process");

  let ps;
  //...
  ps = fork(`${__dirname}/../out-tsc/server-app/main.js`, [], {
    cwd: `${__dirname}/../`,
  });

You are the man.

When I try to make a fetch() request I get a CORS violation. Not sure how to handle this locally.

When I try to make a fetch() request I get a CORS violation. Not sure how to handle this locally.

Enable CORS (https://expressjs.com/en/resources/middleware/cors.html