core/input/keyboard.js

   1 /*
   2  * noVNC: HTML5 VNC client
   3  * Copyright (C) 2012 Joel Martin
   4  * Copyright (C) 2013 Samuel Mannehed for Cendio AB
   5  * Licensed under MPL 2.0 or any later version (see LICENSE.txt)
   6  */
   7
   8 import * as Log from '../util/logging.js';
   9 import { stopEvent } from '../util/events.js';
  10 import * as KeyboardUtil from "./util.js";
  11 import KeyTable from "./keysym.js";
  12 import * as browser from "../util/browser.js";
  13
  14 //
  15 // Keyboard event handler
  16 //
  17
  18 export default function Keyboard(target) {
  19     this._target = target || null;
  20
  21     this._keyDownList = {};         // List of depressed keys
  22                                     // (even if they are happy)
  23     this._pendingKey = null;        // Key waiting for keypress
  24     this._altGrArmed = false;       // Windows AltGr detection
  25
  26     // keep these here so we can refer to them later
  27     this._eventHandlers = {
  28         'keyup': this._handleKeyUp.bind(this),
  29         'keydown': this._handleKeyDown.bind(this),
  30         'keypress': this._handleKeyPress.bind(this),
  31         'blur': this._allKeysUp.bind(this)
  32     };
  33 };
  34
  35 Keyboard.prototype = {
  36     // ===== EVENT HANDLERS =====
  37
  38     onkeyevent: function () {},     // Handler for key press/release
  39
  40     // ===== PRIVATE METHODS =====
  41
  42     _sendKeyEvent: function (keysym, code, down) {
  43         if (down) {
  44             this._keyDownList[code] = keysym;
  45         } else {
  46             // Do we really think this key is down?
  47             if (!(code in this._keyDownList)) {
  48                 return;
  49             }
  50             delete this._keyDownList[code];
  51         }
  52
  53         Log.Debug("onkeyevent " + (down ? "down" : "up") +
  54                   ", keysym: " + keysym, ", code: " + code);
  55         this.onkeyevent(keysym, code, down);
  56     },
  57
  58     _getKeyCode: function (e) {
  59         var code = KeyboardUtil.getKeycode(e);
  60         if (code !== 'Unidentified') {
  61             return code;
  62         }
  63
  64         // Unstable, but we don't have anything else to go on
  65         // (don't use it for 'keypress' events thought since
  66         // WebKit sets it to the same as charCode)
  67         if (e.keyCode && (e.type !== 'keypress')) {
  68             // 229 is used for composition events
  69             if (e.keyCode !== 229) {
  70                 return 'Platform' + e.keyCode;
  71             }
  72         }
  73
  74         // A precursor to the final DOM3 standard. Unfortunately it
  75         // is not layout independent, so it is as bad as using keyCode
  76         if (e.keyIdentifier) {
  77             // Non-character key?
  78             if (e.keyIdentifier.substr(0, 2) !== 'U+') {
  79                 return e.keyIdentifier;
  80             }
  81
  82             var codepoint = parseInt(e.keyIdentifier.substr(2), 16);
  83             var char = String.fromCharCode(codepoint);
  84             // Some implementations fail to uppercase the symbols
  85             char = char.toUpperCase();
  86
  87             return 'Platform' + char.charCodeAt();
  88         }
  89
  90         return 'Unidentified';
  91     },
  92
  93     _handleKeyDown: function (e) {
  94         var code = this._getKeyCode(e);
  95         var keysym = KeyboardUtil.getKeysym(e);
  96
  97         // Windows doesn't have a proper AltGr, but handles it using
  98         // fake Ctrl+Alt. However the remote end might not be Windows,
  99         // so we need to merge those in to a single AltGr event. We
 100         // detect this case by seeing the two key events directly after
 101         // each other with a very short time between them (<50ms).
 102         if (this._altGrArmed) {
 103             this._altGrArmed = false;
 104             clearTimeout(this._altGrTimeout);
 105
 106             if ((code === "AltRight") &&
 107                 ((e.timeStamp - this._altGrCtrlTime) < 50)) {
 108                 // FIXME: We fail to detect this if either Ctrl key is
 109                 //        first manually pressed as Windows then no
 110                 //        longer sends the fake Ctrl down event. It
 111                 //        does however happily send real Ctrl events
 112                 //        even when AltGr is already down. Some
 113                 //        browsers detect this for us though and set the
 114                 //        key to "AltGraph".
 115                 keysym = KeyTable.XK_ISO_Level3_Shift;
 116             } else {
 117                 this._sendKeyEvent(KeyTable.XK_Control_L, "ControlLeft", true);
 118             }
 119         }
 120
 121         // We cannot handle keys we cannot track, but we also need
 122         // to deal with virtual keyboards which omit key info
 123         // (iOS omits tracking info on keyup events, which forces us to
 124         // special treat that platform here)
 125         if ((code === 'Unidentified') || browser.isIOS()) {
 126             if (keysym) {
 127                 // If it's a virtual keyboard then it should be
 128                 // sufficient to just send press and release right
 129                 // after each other
 130                 this._sendKeyEvent(keysym, code, true);
 131                 this._sendKeyEvent(keysym, code, false);
 132             }
 133
 134             stopEvent(e);
 135             return;
 136         }
 137
 138         // Alt behaves more like AltGraph on macOS, so shuffle the
 139         // keys around a bit to make things more sane for the remote
 140         // server. This method is used by RealVNC and TigerVNC (and
 141         // possibly others).
 142         if (browser.isMac()) {
 143             switch (keysym) {
 144             case KeyTable.XK_Super_L:
 145                 keysym = KeyTable.XK_Alt_L;
 146                 break;
 147             case KeyTable.XK_Super_R:
 148                 keysym = KeyTable.XK_Super_L;
 149                 break;
 150             case KeyTable.XK_Alt_L:
 151                 keysym = KeyTable.XK_Mode_switch;
 152                 break;
 153             case KeyTable.XK_Alt_R:
 154                 keysym = KeyTable.XK_ISO_Level3_Shift;
 155                 break;
 156             }
 157         }
 158
 159         // Is this key already pressed? If so, then we must use the
 160         // same keysym or we'll confuse the server
 161         if (code in this._keyDownList) {
 162             keysym = this._keyDownList[code];
 163         }
 164
 165         // macOS doesn't send proper key events for modifiers, only
 166         // state change events. That gets extra confusing for CapsLock
 167         // which toggles on each press, but not on release. So pretend
 168         // it was a quick press and release of the button.
 169         if (browser.isMac() && (code === 'CapsLock')) {
 170             this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', true);
 171             this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', false);
 172             stopEvent(e);
 173             return;
 174         }
 175
 176         // If this is a legacy browser then we'll need to wait for
 177         // a keypress event as well
 178         // (IE and Edge has a broken KeyboardEvent.key, so we can't
 179         // just check for the presence of that field)
 180         if (!keysym && (!e.key || browser.isIE() || browser.isEdge())) {
 181             this._pendingKey = code;
 182             // However we might not get a keypress event if the key
 183             // is non-printable, which needs some special fallback
 184             // handling
 185             setTimeout(this._handleKeyPressTimeout.bind(this), 10, e);
 186             return;
 187         }
 188
 189         this._pendingKey = null;
 190         stopEvent(e);
 191
 192         // Possible start of AltGr sequence? (see above)
 193         if ((code === "ControlLeft") && browser.isWindows() &&
 194             !("ControlLeft" in this._keyDownList)) {
 195             this._altGrArmed = true;
 196             this._altGrTimeout = setTimeout(this._handleAltGrTimeout.bind(this), 100);
 197             this._altGrCtrlTime = e.timeStamp;
 198             return;
 199         }
 200
 201         this._sendKeyEvent(keysym, code, true);
 202     },
 203
 204     // Legacy event for browsers without code/key
 205     _handleKeyPress: function (e) {
 206         stopEvent(e);
 207
 208         // Are we expecting a keypress?
 209         if (this._pendingKey === null) {
 210             return;
 211         }
 212
 213         var code = this._getKeyCode(e);
 214         var keysym = KeyboardUtil.getKeysym(e);
 215
 216         // The key we were waiting for?
 217         if ((code !== 'Unidentified') && (code != this._pendingKey)) {
 218             return;
 219         }
 220
 221         code = this._pendingKey;
 222         this._pendingKey = null;
 223
 224         if (!keysym) {
 225             Log.Info('keypress with no keysym:', e);
 226             return;
 227         }
 228
 229         this._sendKeyEvent(keysym, code, true);
 230     },
 231     _handleKeyPressTimeout: function (e) {
 232         // Did someone manage to sort out the key already?
 233         if (this._pendingKey === null) {
 234             return;
 235         }
 236
 237         var code, keysym;
 238
 239         code = this._pendingKey;
 240         this._pendingKey = null;
 241
 242         // We have no way of knowing the proper keysym with the
 243         // information given, but the following are true for most
 244         // layouts
 245         if ((e.keyCode >= 0x30) && (e.keyCode <= 0x39)) {
 246             // Digit
 247             keysym = e.keyCode;
 248         } else if ((e.keyCode >= 0x41) && (e.keyCode <= 0x5a)) {
 249             // Character (A-Z)
 250             var char = String.fromCharCode(e.keyCode);
 251             // A feeble attempt at the correct case
 252             if (e.shiftKey)
 253                 char = char.toUpperCase();
 254             else
 255                 char = char.toLowerCase();
 256             keysym = char.charCodeAt();
 257         } else {
 258             // Unknown, give up
 259             keysym = 0;
 260         }
 261
 262         this._sendKeyEvent(keysym, code, true);
 263     },
 264
 265     _handleKeyUp: function (e) {
 266         stopEvent(e);
 267
 268         var code = this._getKeyCode(e);
 269
 270         // We can't get a release in the middle of an AltGr sequence, so
 271         // abort that detection
 272         if (this._altGrArmed) {
 273             this._altGrArmed = false;
 274             clearTimeout(this._altGrTimeout);
 275             this._sendKeyEvent(KeyTable.XK_Control_L, "ControlLeft", true);
 276         }
 277
 278         // See comment in _handleKeyDown()
 279         if (browser.isMac() && (code === 'CapsLock')) {
 280             this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', true);
 281             this._sendKeyEvent(KeyTable.XK_Caps_Lock, 'CapsLock', false);
 282             return;
 283         }
 284
 285         this._sendKeyEvent(this._keyDownList[code], code, false);
 286     },
 287
 288     _handleAltGrTimeout: function () {
 289         this._altGrArmed = false;
 290         clearTimeout(this._altGrTimeout);
 291         this._sendKeyEvent(KeyTable.XK_Control_L, "ControlLeft", true);
 292     },
 293
 294     _allKeysUp: function () {
 295         Log.Debug(">> Keyboard.allKeysUp");
 296         for (var code in this._keyDownList) {
 297             this._sendKeyEvent(this._keyDownList[code], code, false);
 298         };
 299         Log.Debug("<< Keyboard.allKeysUp");
 300     },
 301
 302     // ===== PUBLIC METHODS =====
 303
 304     grab: function () {
 305         //Log.Debug(">> Keyboard.grab");
 306         var c = this._target;
 307
 308         c.addEventListener('keydown', this._eventHandlers.keydown);
 309         c.addEventListener('keyup', this._eventHandlers.keyup);
 310         c.addEventListener('keypress', this._eventHandlers.keypress);
 311
 312         // Release (key up) if window loses focus
 313         window.addEventListener('blur', this._eventHandlers.blur);
 314
 315         //Log.Debug("<< Keyboard.grab");
 316     },
 317
 318     ungrab: function () {
 319         //Log.Debug(">> Keyboard.ungrab");
 320         var c = this._target;
 321
 322         c.removeEventListener('keydown', this._eventHandlers.keydown);
 323         c.removeEventListener('keyup', this._eventHandlers.keyup);
 324         c.removeEventListener('keypress', this._eventHandlers.keypress);
 325         window.removeEventListener('blur', this._eventHandlers.blur);
 326
 327         // Release (key up) all keys that are in a down state
 328         this._allKeysUp();
 329
 330         //Log.Debug(">> Keyboard.ungrab");
 331     },
 332 };