Add support for DesktopName extension

This extension allows session name to be changed during runtime.

kasmweb/core/encodings.js

@@ -20,6 +20,7 @@ export const encodings = {
     pseudoEncodingLastRect: -224,
     pseudoEncodingCursor: -239,
     pseudoEncodingQEMUExtendedKeyEvent: -258,
+    pseudoEncodingDesktopName: -307,
     pseudoEncodingExtendedDesktopSize: -308,
     pseudoEncodingXvp: -309,
     pseudoEncodingFence: -312,

kasmweb/core/rfb.js

@@ -542,6 +542,13 @@ export default class RFB extends EventTargetMixin {
         this.focus();
     }
 
+    _setDesktopName(name) {
+        this._fb_name = name;
+        this.dispatchEvent(new CustomEvent(
+            "desktopname",
+            { detail: { name: this._fb_name } }));
+    }
+
     _windowResize(event) {
         // If the window resized then our screen element might have
         // as well. Update the viewport dimensions.
@@ -1256,7 +1263,7 @@ export default class RFB extends EventTargetMixin {
         /* Connection name/title */
         const name_length = this._sock.rQshift32();
         if (this._sock.rQwait('server init name', name_length, 24)) { return false; }
-        this._fb_name = decodeUTF8(this._sock.rQshiftStr(name_length));
+        let name = decodeUTF8(this._sock.rQshiftStr(name_length));
 
         if (this._rfb_tightvnc) {
             if (this._sock.rQwait('TightVNC extended server init header', 8, 24 + name_length)) { return false; }
@@ -1296,10 +1303,7 @@ export default class RFB extends EventTargetMixin {
                   ", blue_shift: " + blue_shift);
 
         // we're past the point where we could backtrack, so it's safe to call this
-        this.dispatchEvent(new CustomEvent(
-            "desktopname",
-            { detail: { name: this._fb_name } }));
-
+        this._setDesktopName(name);
         this._resize(width, height);
 
         if (!this._viewOnly) { this._keyboard.grab(); }
@@ -1383,6 +1387,7 @@ export default class RFB extends EventTargetMixin {
         encs.push(encodings.pseudoEncodingXvp);
         encs.push(encodings.pseudoEncodingFence);
         encs.push(encodings.pseudoEncodingContinuousUpdates);
+        encs.push(encodings.pseudoEncodingDesktopName);
         if (this._hasWebp())
             encs.push(encodings.pseudoEncodingWEBP);
 
@@ -1694,6 +1699,9 @@ export default class RFB extends EventTargetMixin {
                 }
                 return true;
 
+            case encodings.pseudoEncodingDesktopName:
+                return this._handleDesktopName();
+
             case encodings.pseudoEncodingDesktopSize:
                 this._resize(this._FBU.width, this._FBU.height);
                 return true;
@@ -1743,6 +1751,25 @@ export default class RFB extends EventTargetMixin {
         return true;
     }
 
+    _handleDesktopName() {
+        if (this._sock.rQwait("DesktopName", 4)) {
+            return false;
+        }
+
+        let length = this._sock.rQshift32();
+
+        if (this._sock.rQwait("DesktopName", length, 4)) {
+            return false;
+        }
+
+        let name = this._sock.rQshiftStr(length);
+        name = decodeUTF8(name);
+
+        this._setDesktopName(name);
+
+        return true;
+    }
+
     _handleExtendedDesktopSize() {
         if (this._sock.rQwait("ExtendedDesktopSize", 4)) {
             return false;

kasmweb/tests/test.rfb.js

@@ -41,6 +41,13 @@ function push32(arr, num) {
              num & 0xFF);
 }
 
+function pushString(arr, string) {
+    let utf8 = unescape(encodeURIComponent(string));
+    for (let i = 0; i < utf8.length; i++) {
+        arr.push(utf8.charCodeAt(i));
+    }
+}
+
 describe('Remote Frame Buffer Protocol Client', function () {
     let clock;
     let raf;
@@ -2128,6 +2135,21 @@ describe('Remote Frame Buffer Protocol Client', function () {
                     send_fbu_msg([{ x: 0, y: 0, width: 0, height: 0, encoding: -224}], [[]], client, 100);
                     expect(client._FBU.rects).to.equal(0);
                 });
+
+                it('should handle the DesktopName pseudo-encoding', function () {
+                    let data = [];
+                    push32(data, 9);
+                    pushString(data, "some name");
+
+                    const spy = sinon.spy();
+                    client.addEventListener("desktopname", spy);
+
+                    send_fbu_msg([{ x: 0, y: 0, width: 0, height: 0, encoding: -307 }], [data], client);
+
+                    expect(client._fb_name).to.equal('some name');
+                    expect(spy).to.have.been.calledOnce;
+                    expect(spy.args[0][0].detail.name).to.equal('some name');
+                });
             });
         });