rudifa/Electron IPC Pattern #2

## Electron IPC Pattern #2
// 1. Renderer defines a listener that will, on the user click,
//    call asynchronously window.electronAPI.openFile(),
//    which is defined by preload.
//    Function openFile returns the data
//    (the file path selected by the user) that the handler in main
//    obtained from the OS dialog.
//    The listener updates the html text with this data.

// 2. Preload defines function openFile that calls invoke(<channel>)
//    which will be handled by the main

// 3. Main defines a function to hanndle the fileOpen request
//    by launching the OS File Open dialog,
//    and attaches it (below) to handle the request comming in
//    (from renderer)
//    on success, the function returns the filepath selected by the user

// 3a. handleFileOpen is attached here to handle the request on the channel

## index.html
<!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>Dialog</title>
  </head>
  <body>
    <button type="button" id="btn">Open a File</button>
    File path: <strong id="filePath"></strong>
    <script src='./renderer.js'></script>
  </body>
</html>

## main.js
const {app, BrowserWindow, ipcMain, dialog} = require('electron')
const path = require('path')

// 3. Main defines a function to hanndle the fileOpen request
//    by launching the OS File Open dialog,
//    and attaches it (below) to handle the request comming in
//    (from renderer)
//    on success, the function returns the filepath selected by the user
async function handleFileOpen() {
  const { canceled, filePaths } = await dialog.showOpenDialog()
  if (canceled) {
    return
  } else {
    return filePaths[0]
  }
}

function createWindow () {
  const mainWindow = new BrowserWindow({
    webPreferences: {
      preload: path.join(__dirname, 'preload.js')
    }
  })
  mainWindow.loadFile('index.html')
}

app.whenReady().then(() => {
  // 3a. handleFileOpen is attached here to handle the request on the channel
  ipcMain.handle('dialog:openFile', handleFileOpen)
  createWindow()
  app.on('activate', function () {
    if (BrowserWindow.getAllWindows().length === 0) createWindow()
  })
})

app.on('window-all-closed', function () {
  if (process.platform !== 'darwin') app.quit()
})

## package.json
{
  "name": "real-chairs-curve-0p1c0",
  "productName": "real-chairs-curve-0p1c0",
  "description": "My Electron application description",
  "keywords": [],
  "main": "./main.js",
  "version": "1.0.0",
  "author": "rudifarkas",
  "scripts": {
    "start": "electron ."
  },
  "dependencies": {},
  "devDependencies": {
    "electron": "21.2.0"
  }
}

## preload.js
const { contextBridge, ipcRenderer } = require('electron')

// 2. Preload defines function openFile that calls invoke(<channel>)
//    which will be handled by the main

contextBridge.exposeInMainWorld('electronAPI',{
  openFile: () => ipcRenderer.invoke('dialog:openFile')
})

## renderer.js
// 1. Renderer defines a listener that will, on the user click,
//    call asynchronously window.electronAPI.openFile(),
//    which is defined by preload.
//    Function openFile returns the data
//    (the file path selected by the user) that the handler in main
//    obtained from the OS dialog.
//    The listener updates the html text with this data.

const btn = document.getElementById('btn')
const filePathElement = document.getElementById('filePath')

btn.addEventListener('click', async () => {
  const filePath = await window.electronAPI.openFile()
  filePathElement.innerText = filePath
})

## styles.css
/* styles.css */

/* Add styles here to customize the appearance of your app */
	// 1. Renderer defines a listener that will, on the user click,
	// call asynchronously window.electronAPI.openFile(),
	// which is defined by preload.
	// Function openFile returns the data
	// (the file path selected by the user) that the handler in main
	// obtained from the OS dialog.
	// The listener updates the html text with this data.

	// 2. Preload defines function openFile that calls invoke(<channel>)
	// which will be handled by the main

	// 3. Main defines a function to hanndle the fileOpen request
	// by launching the OS File Open dialog,
	// and attaches it (below) to handle the request comming in
	// (from renderer)
	// on success, the function returns the filepath selected by the user

	// 3a. handleFileOpen is attached here to handle the request on the channel
	<!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>Dialog</title>
	</head>
	<body>
	<button type="button" id="btn">Open a File</button>
	File path: <strong id="filePath"></strong>
	<script src='./renderer.js'></script>
	</body>
	</html>
	const {app, BrowserWindow, ipcMain, dialog} = require('electron')
	const path = require('path')

	// 3. Main defines a function to hanndle the fileOpen request
	// by launching the OS File Open dialog,
	// and attaches it (below) to handle the request comming in
	// (from renderer)
	// on success, the function returns the filepath selected by the user
	async function handleFileOpen() {
	const { canceled, filePaths } = await dialog.showOpenDialog()
	if (canceled) {
	return
	} else {
	return filePaths[0]
	}
	}

	function createWindow () {
	const mainWindow = new BrowserWindow({
	webPreferences: {
	preload: path.join(__dirname, 'preload.js')
	}
	})
	mainWindow.loadFile('index.html')
	}

	app.whenReady().then(() => {
	// 3a. handleFileOpen is attached here to handle the request on the channel
	ipcMain.handle('dialog:openFile', handleFileOpen)
	createWindow()
	app.on('activate', function () {
	if (BrowserWindow.getAllWindows().length === 0) createWindow()
	})
	})

	app.on('window-all-closed', function () {
	if (process.platform !== 'darwin') app.quit()
	})
	{
	"name": "real-chairs-curve-0p1c0",
	"productName": "real-chairs-curve-0p1c0",
	"description": "My Electron application description",
	"keywords": [],
	"main": "./main.js",
	"version": "1.0.0",
	"author": "rudifarkas",
	"scripts": {
	"start": "electron ."
	},
	"dependencies": {},
	"devDependencies": {
	"electron": "21.2.0"
	}
	}
	const { contextBridge, ipcRenderer } = require('electron')

	// 2. Preload defines function openFile that calls invoke(<channel>)
	// which will be handled by the main

	contextBridge.exposeInMainWorld('electronAPI',{
	openFile: () => ipcRenderer.invoke('dialog:openFile')
	})
	/* styles.css */

	/* Add styles here to customize the appearance of your app */