CODEWITHSUNDEEP
expresselectronelectron-builder
somerandomusername
somerandomusername

Reputation: 2023

Using 'express' inside Electron main thread, cannot find module

I'm trying to use express library in main.js file. It works fine on my dev build, but when I package the app I get

Error: Cannot find module 'express'

I'm not quite sure how electron main thread works, is it packaged separately by some other build tool, and do I need to define(include) package manually? My app is packaged by webpack, and I have included libraries in package.json. Every sample I have found just includes express library and moves on, I can't find any additional steps for this.

package.json

{
  "name": "basic-electron-react-boilerplate",
  "version": "0.7.0",
  "description": "Minimal and modern react+electron+webpack boilerplate",
  "author": "Phillip Barbiero",
  "homepage": "https://github.com/pbarbiero/basic-electron-react-boilerplate",
  "repository": {
    "type": "git",
    "url": "https://github.com/pbarbiero/basic-electron-react-boilerplate.git"
  },
  "build": {
    "appId": "your.id",
    "mac": {
      "category": "your.app.category.type"
    }
  },
  "license": "MIT",
  "main": "main.js",
  "scripts": {
    "prod": "webpack --config webpack.build.config.js && electron --noDevServer .",
    "test": "node  test.js",
    "dev": "webpack-dev-server --hot --host 0.0.0.0 --config=./webpack.dev.config.js",
    "build": "webpack --config webpack.build.config.js",
    "package": "webpack --config webpack.build.config.js",
    "postpackage": "electron-packager ./ --out=./builds",
    "pack": "electron-builder --dir",
    "dist": "electron-builder"
  },
  "devDependencies": {
    "@babel/core": "^7.1.2",
    "@babel/plugin-proposal-class-properties": "^7.1.0",
    "@babel/plugin-proposal-export-default-from": "^7.0.0",
    "@babel/plugin-proposal-object-rest-spread": "^7.0.0",
    "@babel/preset-env": "^7.1.0",
    "@babel/preset-es2017": "^7.0.0-beta.53",
    "@babel/preset-react": "^7.0.0",
    "babel-core": "^6.24.1",
    "babel-loader": "^8.0.4",
    "babel-plugin-lodash": "^3.3.4",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-es2016": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "babel-preset-stage-2": "^6.24.1",
    "babili-webpack-plugin": "^0.1.2",
    "body-parser": "^1.18.3",
    "css-loader": "^0.28.1",
    "electron": "^1.7.8",
    "electron-builder": "^20.28.4",
    "electron-packager": "^9.1.0",
    "express": "^4.16.4",
    "extract-text-webpack-plugin": "^3.0.1",
    "file-loader": "^1.1.5",
    "html-webpack-plugin": "^2.28.0",
    "react": "^16.0.0",
    "react-dom": "^16.0.0",
    "request": "^2.88.0",
    "style-loader": "^0.19.0",
    "webpack": "^3.6.0",
    "webpack-dev-server": "^2.4.5"
  },
  "dependencies": {
    "electron-fetch": "^1.2.1",
    "electron-require": "^0.3.0",
    "express": "^4.16.4",
    "faker": "^4.1.0",
    "lodash": "^4.17.11",
    "moment": "^2.22.2",
    "rc-time-picker": "^3.4.0",
    "react-async-script-loader": "^0.3.0",
    "react-dropdown": "^1.6.2",
    "react-places-autocomplete": "^7.2.0",
    "request": "^2.88.0",
    "resolve-url-loader": "^3.0.0",
    "semantic-ui-css": "^2.4.1",
    "semantic-ui-react": "^0.82.5",
    "styled-components": "^4.0.2"
  }
}

Upvotes: 5

Views: 2096

Answers (1)

Bharathvaj Ganesan
Bharathvaj Ganesan

Reputation: 3194

You can run Express server inside Electron. Here is a sample repo for running express inside Electron.

You can fork a child process to run express app as follows

app = require("electron").remote.app),
node = require("child_process").fork(
         `${app.getAppPath()}/express-app/bin/www`,
         [],
         {
             stdio: ["pipe", "pipe", "pipe", "ipc"]
         });

The express app used here is a generated one using express-generator.

The problem with your approach is that you are maintaining a single package.json file for both Electron and Express. Checkout Electron-React-Boilerplate, here i have two separate npm installation locations one is for Electron alone and other is for React stuffs. Electron-packager and Electron-builder works using this pattern. This is the reason why your process on main thread throws

Error: Cannot find module 'express'

Upvotes: 3

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