Support hosting the frontend on a Unix socket (#17123)

lib/extension/frontend.ts

@@ -74,8 +74,13 @@ export default class Frontend extends Extension {
         this.wss = new WebSocket.Server({noServer: true});
         this.wss.on('connection', this.onWebSocketConnection);
 
-        this.server.listen(this.port, this.host);
-        logger.info(`Started frontend on port ${this.host}:${this.port}`);
+        if (this.host.startsWith('/')) {
+            this.server.listen(this.host);
+            logger.info(`Started frontend on socket ${this.host}`);
+        } else {
+            this.server.listen(this.port, this.host);
+            logger.info(`Started frontend on port ${this.host}:${this.port}`);
+        }
     }
 
     override async stop(): Promise<void> {

lib/util/settings.schema.json

@@ -366,14 +366,15 @@
             "port": {
               "type": "number",
               "title": "Port",
-              "description": "Frontend binding port",
+              "description": "Frontend binding port. Ignored when using a unix domain socket",
               "default": 8080,
               "requiresRestart": true
             },
             "host": {
               "type": "string",
               "title": "Bind host",
-              "description": "Frontend binding host",
+              "description": "Frontend binding host. Binds to a unix socket when an absolute path is given instead.",
+              "examples": ["127.0.0.1", "/run/zigbee2mqtt/zigbee2mqtt.sock"],
               "default": "0.0.0.0",
               "requiresRestart": true
             },

test/frontend.test.js

@@ -128,6 +128,32 @@ describe('Frontend', () => {
         expect(mockWSClient.implementation.terminate).toHaveBeenCalledTimes(1);
         expect(mockHTTP.implementation.close).toHaveBeenCalledTimes(1);
         expect(mockWS.implementation.close).toHaveBeenCalledTimes(1);
+        mockWS.implementation.close.mockClear();
+        mockHTTP.implementation.close.mockClear();
+        mockHTTP.implementation.listen.mockClear();
+        mockHTTPS.implementation.listen.mockClear();
+    });
+
+    it('Start/stop unix socket', async () => {
+        settings.set(['frontend'], {host: "/tmp/zigbee2mqtt.sock"});
+        controller = new Controller(jest.fn(), jest.fn());
+        await controller.start();
+        expect(mockNodeStatic.variables.path).toBe("my/dummy/path");
+        expect(mockHTTP.implementation.listen).toHaveBeenCalledWith("/tmp/zigbee2mqtt.sock");
+        const mockWSClient = {
+            implementation: {
+                terminate: jest.fn(),
+                send: jest.fn(),
+            },
+            events: {},
+        };
+        mockWS.implementation.clients.push(mockWSClient.implementation);
+        await controller.stop();
+        expect(mockWSClient.implementation.terminate).toHaveBeenCalledTimes(1);
+        expect(mockHTTP.implementation.close).toHaveBeenCalledTimes(1);
+        expect(mockWS.implementation.close).toHaveBeenCalledTimes(1);
+        mockWS.implementation.close.mockClear();
+        mockHTTP.implementation.close.mockClear();
         mockHTTP.implementation.listen.mockClear();
         mockHTTPS.implementation.listen.mockClear();
     });