Initial commit

.backup/servers/gateway/functions.js

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+/*
+    ! /servers/gateway/functions.js – Central Gateway Server Functions
+    ? This modules exports the functionality for the express gateway server
+*/
+
+// % import nodejs dependencies
+const WebSocket = require('ws');
+
+// % core variables
+const ip = process.env.INTERNAL_HOST_IP;
+const port = process.env.INTERNAL_GATEWAY_PORT;
+
+// % create a reference for the websocket client
+let wsClient = null;
+
+// % create an event emitter for the gateway
+const EventEmitter = require('events');
+const gatewayEvents = new EventEmitter();
+
+// $ helper: send messages through websocket
+function sendToWs(payload) {
+    if (wsClient && wsClient.readyState === WebSocket.OPEN) {
+        wsClient.send(JSON.stringify(payload));
+    } else {
+        console.error('WebSocket not connected.');
+    }
+}
+
+// $ server start function
+async function boot(server) {
+    // ~ start express server
+    server.listen(port, ip, () => {
+        console.info(`Express server is now running on http://${ip}:${port}`);
+    });
+
+    // ~ connect to the websocket server
+    const wsUrl = `ws://${process.env.INTERNAL_HOST_IP}:${process.env.INTERNAL_WEBSOCKET_PORT}?key=${process.env.INTERNAL_SECRET}&codename=gateway`;
+    wsClient = new WebSocket(wsUrl);
+
+    wsClient.on('open', () => {
+        console.info('Connected to central websocket server');
+    });
+
+    wsClient.on('message', (data) => {
+        const msg = JSON.parse(data);
+        gatewayEvents.emit('ws_message', msg);
+    });
+
+    wsClient.on('error', (err) => {
+        console.error('WebSocket error:', err.message);
+    });
+
+    // ~ return running express server reference
+    return server;
+};
+
+// $ server shutdown function
+async function shutdown(server) {
+    // ~ close websocket server
+    if (wsClient) {
+        wsClient.close();
+        wsClient = null;
+    }
+
+    // ~ shutdown running express server
+    return new Promise((resolve) => {
+        server.close(() => {
+            console.info('Express server shut down.');
+            resolve(server);
+        });
+    });
+};
+
+// $ server restart function
+async function restart(server) {
+    // ~ shutdown the running express server
+    await shutdown(server);
+
+    // ~ restart the express server
+    await boot(server);
+
+    // ~ return the server reference
+    return server;
+};
+
+// $ server status function
+async function status(server) {
+    // ~ get and return server listening status
+    return server.listening ? 'online' : 'offline';
+};
+
+// § export server functions module
+module.exports = { boot, shutdown, restart, status, sendToWs, gatewayEvents };