Push-to-Talk Support for Jitsi

README.md

@@ -141,7 +141,14 @@ package for 64 bit Linux:
  1. Follow the instructions in 'Building From Source' above
  2. `node_modules/.bin/build -l --x64`
 
-All Electron packages go into `electron_app/dist/`
+All electron packages go into `electron_app/dist/`.
+
+Electron Specific Features
+--------------------------
+
+The electron version of Riot contains some features that are only possible from electron rather than within a browser window. This includes the "Push-to-Talk" feature, which allows you to toggle your microphone during a call even if Riot is not in focus.
+
+This requires the use of a native node module called [iohook](https://github.com/matrix-org/iohook/). Native node modules are written in C, and by default during the build of Riot the compiled binaries will be downloaded from npm. If you would like to build this module from source yourself, please read [Compiling iohook](docs/native_node_modules.md#compiling-iohook).
 
 Many thanks to @aviraldg for the initial work on the Electron integration.
 

docs/native_node_modules.md

@@ -0,0 +1,40 @@
+# Native Node Modules
+
+Since v???, the electron version of Riot can make use of native node modules.
+These allow Riot to integrate with the desktop in ways that a browser cannot.
+
+While handy, these modules must be compiled and are thus downloaded
+pre-compiled during build so that a single OS can compile Riot for all
+platforms. If you would like to compile the native node modules from source,
+as is done for Riot releases, instead of trusting binaries hosted on npm,
+then please read on.
+
+Do note that compiling a module for a particular operating system
+(Linux/Mac/Windows) and will need to be done on that operating system.
+
+## Compiling iohook
+
+[iohook](https://github.com/matrix-org/iohook/) is a native node module
+written in C/C++ that allows for cross-platform capturing of keystrokes. This
+is used for providing Push-to-Talk functionality (pressing a key to toggle
+the microphone in a call) and is ONLY enabled during a call and while setting
+the keybinding in settings.
+
+If you would like to rebuild the module yourself and replace the downloaded
+binaries, then first make sure you have the following dependencies. Then
+simply execute `build-native-modules.sh` with the following flags:
+
+```bash
+./scripts/build-native-modules.sh -e 4.2.6 -a 69 -i
+```
+
+`-e` specifies the electron version, `-a` specifies the electron ABI version,
+and `-i` tells the script to build iohook and then install it.
+
+If you'd just like to build the module without installing it, use `-I` instead.
+
+```bash
+./scripts/build-native-modules.sh -e 4.2.6 -a 69 -I
+```
+
+To then start Electron, use `npx electron .`. To package, use `build -wml -ia32 --x64`.

electron_app/package.json

@@ -9,7 +9,19 @@
     "auto-launch": "^5.0.1",
     "electron-store": "^2.0.0",
     "electron-window-state": "^4.1.0",
+    "iohook": "^0.4.2",
     "minimist": "^1.2.0",
     "png-to-ico": "^1.0.2"
-  }
+  },
+  "cmake-js": {
+    "runtime": "electron",
+    "runtimeVersion": "4.2.6"
+  },
+  "supportedTargets": [
+    [
+      "electron",
+      "4.2.6",
+      "69"
+    ]
+  ]
 }

electron_app/src/electron-main.js

@@ -27,6 +27,7 @@ const argv = require('minimist')(process.argv);
 const {app, ipcMain, powerSaveBlocker, BrowserWindow, Menu, autoUpdater, protocol} = require('electron');
 const AutoLaunch = require('auto-launch');
 const path = require('path');
+const ioHook = require('iohook');
 
 const tray = require('./tray');
 const vectorMenu = require('./vectormenu');
@@ -369,6 +370,13 @@ app.on('ready', () => {
             return false;
         }
     });
+    mainWindow.on('blur', () => {
+        // Stop recording keypresses if Riot loses focus
+        // Used for Push-To-Talk, keypress recording only triggered when setting
+        // a global shortcut in Settings
+        mainWindow.webContents.send('window-blurred');
+        stopListeningKeys();
+    });
 
     if (process.platform === 'win32') {
         // Handle forward/backward mouse buttons in Windows
@@ -411,6 +419,92 @@ app.on('second-instance', (ev, commandLine, workingDirectory) => {
     }
 });
 
+// Counter for keybindings we have registered
+let ioHookTasks = 0;
+
+// Limit for amount of keybindings that can be
+// registered at once.
+const keybindingRegistrationLimit = 1;
+
+// Fires when a global keybinding is being registered
+ipcMain.on('register-keybinding', function(ev, keybinding) {
+    // Prevent registering more than the defined limit
+    if (ioHookTasks >= keybindingRegistrationLimit) {
+        ioHookTasks = keybindingRegistrationLimit;
+        return;
+    }
+
+    // Start listening for global keyboard shortcuts
+    if (ioHookTasks <= 0) {
+        ioHookTasks = 0;
+        ioHook.start();
+    }
+    ioHookTasks++;
+
+    ioHook.registerShortcut(keybinding.code, () => {
+        ev.sender.send('keybinding-pressed', keybinding.name);
+    }, () => {
+        ev.sender.send('keybinding-released', keybinding.name);
+    });
+});
+
+// Fires when a global keybinding is being unregistered
+ipcMain.on('unregister-keybinding', function(ev, keybindingCode) {
+    // Stop listening for global keyboard shortcuts if we're
+    // unregistering the last one
+    if (ioHookTasks <= 1) {
+        ioHook.stop();
+    }
+    ioHookTasks--;
+
+    ioHook.unregisterShortcutByKeys(keybindingCode);
+});
+
+// Tell renderer process what key was pressed
+// iohook has its own encoding for keys, so we can't just use a
+// listener in the renderer process to register iohook shortcuts
+let renderProcessID = null;
+const reportKeyEvent = function(keyEvent) {
+    // "this" is the renderer process because we call this method with .bind()
+    renderProcessID.sender.send('keypress', {
+        keydown: keyEvent.type == 'keydown',
+        keycode: keyEvent.keycode,
+    });
+};
+
+// Fires when listening on all keys
+// !!Security note: Ensure iohook is only allowed to listen to keybindings
+// when the browser window is in focus, else an XSS could lead to keylogging
+// Currently, this is achieved by leveraging browserWindow to act on focus loss
+ipcMain.on('start-listening-keys', function(ev, keybindingCode) {
+    // Start recording keypresses
+    if (ioHookTasks <= 0) {
+        ioHookTasks = 0;
+        ioHook.start();
+    }
+    ioHookTasks++;
+
+    renderProcessID = ev;
+    ioHook.on('keydown', reportKeyEvent);
+    ioHook.on('keyup', reportKeyEvent);
+});
+
+const stopListeningKeys = () => {
+    // Stop recording keypresses
+    ioHook.off('keydown', reportKeyEvent);
+    ioHook.off('keyup', reportKeyEvent);
+};
+
+ipcMain.on('stop-listening-keys', () => {
+    if (ioHookTasks <= 1) {
+        ioHookTasks = 1;
+        ioHook.stop();
+    }
+    ioHookTasks--;
+
+    stopListeningKeys();
+});
+
 // Set the App User Model ID to match what the squirrel
 // installer uses for the shortcut icon.
 // This makes notifications work on windows 8.1 (and is