feat: add support for Web Bluetooth pin pairing (#35416)

* feat: add bluetooth pairing handler

* Update docs/api/session.md

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* Update docs/api/session.md

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* docs: update based on review

* Apply suggestions from code review

Co-authored-by: Erick Zhao <erick@hotmail.ca>
Co-authored-by: Charles Kerr <charles@charleskerr.com>

* chore: update docs per review

* chore: cleanup callback per review

Co-authored-by: Charles Kerr <charles@charleskerr.com>
Co-authored-by: Erick Zhao <erick@hotmail.ca>

docs/api/session.md

@@ -823,6 +823,71 @@ app.whenReady().then(() => {
 })
 ```
 
+#### `ses.setBluetoothPairingHandler(handler)` _Windows_ _Linux_
+
+* `handler` Function | null
+  * `details` Object
+    * `deviceId` string
+    * `pairingKind` string - The type of pairing prompt being requested.
+      One of the following values:
+      * `confirm`
+        This prompt is requesting confirmation that the Bluetooth device should
+        be paired.
+      * `confirmPin`
+        This prompt is requesting confirmation that the provided PIN matches the
+        pin displayed on the device.
+      * `providePin`
+        This prompt is requesting that a pin be provided for the device.
+    * `frame` [WebFrameMain](web-frame-main.md)
+    * `pin` string (optional) - The pin value to verify if `pairingKind` is `confirmPin`.
+  * `callback` Function
+    * `response` Object
+      * `confirmed` boolean - `false` should be passed in if the dialog is canceled.
+        If the `pairingKind` is `confirm` or `confirmPin`, this value should indicate
+        if the pairing is confirmed.  If the `pairingKind` is `providePin` the value
+        should be `true` when a value is provided.
+      * `pin` string | null (optional) - When the `pairingKind` is `providePin`
+        this value should be the required pin for the Bluetooth device.
+
+Sets a handler to respond to Bluetooth pairing requests. This handler
+allows developers to handle devices that require additional validation
+before pairing.  When a handler is not defined, any pairing on Linux or Windows
+that requires additional validation will be automatically cancelled.
+macOS does not require a handler because macOS handles the pairing
+automatically.  To clear the handler, call `setBluetoothPairingHandler(null)`.
+
+```javascript
+
+const { app, BrowserWindow, ipcMain, session } = require('electron')
+
+let bluetoothPinCallback = null
+
+function createWindow () {
+  const mainWindow = new BrowserWindow({
+    webPreferences: {
+      preload: path.join(__dirname, 'preload.js')
+    }
+  })
+}
+
+// Listen for an IPC message from the renderer to get the response for the Bluetooth pairing.
+ipcMain.on('bluetooth-pairing-response', (event, response) => {
+  bluetoothPinCallback(response)
+})
+
+mainWindow.webContents.session.setBluetoothPairingHandler((details, callback) => {
+  bluetoothPinCallback = callback
+  // Send a IPC message to the renderer to prompt the user to confirm the pairing.
+  // Note that this will require logic in the renderer to handle this message and
+  // display a prompt to the user.
+  mainWindow.webContents.send('bluetooth-pairing-request', details)
+})
+
+app.whenReady().then(() => {
+  createWindow()
+})
+```
+
 #### `ses.clearHostResolverCache()`
 
 Returns `Promise<void>` - Resolves when the operation is complete.

docs/fiddles/features/web-bluetooth/main.js

@@ -1,10 +1,13 @@
-const {app, BrowserWindow} = require('electron')
+const {app, BrowserWindow, ipcMain} = require('electron')
 const path = require('path')
 
 function createWindow () {
   const mainWindow = new BrowserWindow({
     width: 800,
-    height: 600
+    height: 600,
+    webPreferences: {
+      preload: path.join(__dirname, 'preload.js')
+    }    
   })
 
   mainWindow.webContents.on('select-bluetooth-device', (event, deviceList, callback) => {
@@ -14,6 +17,18 @@ function createWindow () {
     } 
   })
 
+  // Listen for a message from the renderer to get the response for the Bluetooth pairing.
+  ipcMain.on('bluetooth-pairing-response', (event, response) => {
+    bluetoothPinCallback(response)
+  })
+
+  mainWindow.webContents.session.setBluetoothPairingHandler((details, callback) => {
+
+    bluetoothPinCallback = callback
+    // Send a message to the renderer to prompt the user to confirm the pairing.
+    mainWindow.webContents.send('bluetooth-pairing-request', details)
+  })  
+
   mainWindow.loadFile('index.html')
 }
 

docs/fiddles/features/web-bluetooth/preload.js

@@ -0,0 +1,6 @@
+const { contextBridge, ipcRenderer } = require('electron')
+
+contextBridge.exposeInMainWorld('electronAPI', {
+  bluetoothPairingRequest: (callback) => ipcRenderer.on('bluetooth-pairing-request', callback),
+  bluetoothPairingResponse: (response) => ipcRenderer.send('bluetooth-pairing-respnse', response)
+})

docs/fiddles/features/web-bluetooth/renderer.js

@@ -5,4 +5,30 @@ async function testIt() {
   document.getElementById('device-name').innerHTML = device.name || `ID: ${device.id}`
 }
 
-document.getElementById('clickme').addEventListener('click',testIt)
+document.getElementById('clickme').addEventListener('click',testIt)
+
+window.electronAPI.bluetoothPairingRequest((event, details) => {
+  const response = {}
+  
+  switch (details.pairingKind) {
+    case 'confirm': {
+      response.confirmed = confirm(`Do you want to connect to device ${details.deviceId}?`)
+      break
+    }
+    case 'confirmPin': {
+      response.confirmed = confirm(`Does the pin ${details.pin} match the pin displayed on device ${details.deviceId}?`)
+      break
+    }
+    case 'providePin': {
+      const pin = prompt(`Please provide a pin for ${details.deviceId}.`)
+      if (pin) {
+        response.pin = pin
+        response.confirmed = true
+      } else {
+        response.confirmed = false
+      }
+    }
+  }
+
+  window.electronAPI.bluetoothPairingResponse(response)
+})

docs/tutorial/devices.md

@@ -16,6 +16,10 @@ with bluetooth devices. In order to use this API in Electron, developers will
 need to handle the [`select-bluetooth-device` event on the webContents](../api/web-contents.md#event-select-bluetooth-device)
 associated with the device request.
 
+Additionally, [`ses.setBluetoothPairingHandler(handler)`](../api/session.md#sessetbluetoothpairinghandlerhandler-windows-linux)
+can be used to handle pairing to bluetooth devices on Windows or Linux when
+additional validation such as a pin is needed.
+
 ### Example
 
 This example demonstrates an Electron application that automatically selects