Implement EventManager integration and enhance socket event handling

- Added EventManager to SocketHost and SocketUser for improved event handling.
- Introduced new socket event handlers for editing objects, listing objects, and subscribing to object actions.
- Refactored authentication logic to streamline host online status updates.
- Enhanced logging and callback mechanisms for better traceability and responsiveness in socket interactions.

.gitignore

@@ -127,4 +127,6 @@ dist
 .yarn/unplugged
 .yarn/build-state.yml
 .yarn/install-state.gz
-.pnp.*
+.pnp.*
+
+*.DS_STORE

package-lock.json

@@ -9,7 +9,10 @@
       "version": "1.0.0",
       "license": "ISC",
       "dependencies": {
+        "@nats-io/nats-core": "^3.1.0",
+        "@nats-io/transport-node": "^3.1.0",
         "axios": "^1.11.0",
+        "canonical-json": "^0.2.0",
         "date-fns": "^4.1.0",
         "dayjs": "^1.11.13",
         "dotenv": "^17.2.1",
@@ -378,6 +381,51 @@
         "sparse-bitfield": "^3.0.3"
       }
     },
+    "node_modules/@nats-io/nats-core": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/@nats-io/nats-core/-/nats-core-3.1.0.tgz",
+      "integrity": "sha512-xsSkLEGGcqNF+Ru8dMjPmKtfbBeq/U4meuJJX4Zi+5TBHpjpjNjs4YkCBC/pGYWnEum1/vdNPizjE1RdNHCyBg==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@nats-io/nkeys": "2.0.3",
+        "@nats-io/nuid": "2.0.3"
+      }
+    },
+    "node_modules/@nats-io/nkeys": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/@nats-io/nkeys/-/nkeys-2.0.3.tgz",
+      "integrity": "sha512-JVt56GuE6Z89KUkI4TXUbSI9fmIfAmk6PMPknijmuL72GcD+UgIomTcRWiNvvJKxA01sBbmIPStqJs5cMRBC3A==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "tweetnacl": "^1.0.3"
+      },
+      "engines": {
+        "node": ">=18.0.0"
+      }
+    },
+    "node_modules/@nats-io/nuid": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/@nats-io/nuid/-/nuid-2.0.3.tgz",
+      "integrity": "sha512-TpA3HEBna/qMVudy+3HZr5M3mo/L1JPofpVT4t0HkFGkz2Cn9wrlrQC8tvR8Md5Oa9//GtGG26eN0qEWF5Vqew==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">= 18.x"
+      }
+    },
+    "node_modules/@nats-io/transport-node": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/@nats-io/transport-node/-/transport-node-3.1.0.tgz",
+      "integrity": "sha512-k5pH7IOKUetwXOMraVgcB5zG0wibcHOwJJuyuY1/5Q4K0XfBJDnb/IbczP5/JJWwMYfxSL9O+46ojtdBHvHRSw==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@nats-io/nats-core": "3.1.0",
+        "@nats-io/nkeys": "2.0.3",
+        "@nats-io/nuid": "2.0.3"
+      },
+      "engines": {
+        "node": ">= 18.0.0"
+      }
+    },
     "node_modules/@nodelib/fs.scandir": {
       "version": "2.1.5",
       "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.5.tgz",
@@ -1054,6 +1102,15 @@
         "node": ">=6"
       }
     },
+    "node_modules/canonical-json": {
+      "version": "0.2.0",
+      "resolved": "https://registry.npmjs.org/canonical-json/-/canonical-json-0.2.0.tgz",
+      "integrity": "sha512-xeH/NgtNA7kIuKSxopJVdXqCKWyDB79aqxQRQ9FV02fvmqW7DSnjoFyzAUrBpfbwjU6lwTYOLc+HM6KupbsfVQ==",
+      "license": "MIT",
+      "bin": {
+        "canonical-json": "canonical-json.js"
+      }
+    },
     "node_modules/chalk": {
       "version": "4.1.2",
       "resolved": "https://registry.npmjs.org/chalk/-/chalk-4.1.2.tgz",
@@ -6401,6 +6458,12 @@
         "strip-bom": "^3.0.0"
       }
     },
+    "node_modules/tweetnacl": {
+      "version": "1.0.3",
+      "resolved": "https://registry.npmjs.org/tweetnacl/-/tweetnacl-1.0.3.tgz",
+      "integrity": "sha512-6rt+RN7aOi1nGMyC4Xa5DdYiukl2UWCbcJft7YhxReBGQD7OAM8Pbxw6YMo4r2diNEA8FEmu32YOn9rhaiE5yw==",
+      "license": "Unlicense"
+    },
     "node_modules/type-check": {
       "version": "0.4.0",
       "resolved": "https://registry.npmjs.org/type-check/-/type-check-0.4.0.tgz",

package.json

@@ -17,7 +17,10 @@
   "author": "Tom Butcher",
   "license": "ISC",
   "dependencies": {
+    "@nats-io/nats-core": "^3.1.0",
+    "@nats-io/transport-node": "^3.1.0",
     "axios": "^1.11.0",
+    "canonical-json": "^0.2.0",
     "date-fns": "^4.1.0",
     "dayjs": "^1.11.13",
     "dotenv": "^17.2.1",

src/actions/actionmanager.js

@@ -1,6 +1,6 @@
 import log4js from 'log4js';
 import { loadConfig } from '../config.js';
-import { etcdServer } from '../database/etcd.js';
+import { natsServer } from '../database/nats.js';
 import { generateEtcId } from '../utils.js';
 
 const config = loadConfig();
@@ -10,7 +10,7 @@ const logger = log4js.getLogger('Action Manager');
 logger.level = config.server.logLevel;
 
 /**
- * ActionManager handles tracking object updates using Etcd and broadcasts update events via websockets.
+ * ActionManager handles tracking object updates using NATS and broadcasts update events via websockets.
  */
 export class ActionManager {
   constructor(socketClient) {
@@ -20,10 +20,12 @@ export class ActionManager {
 
   async subscribeToObjectActions(id, objectType) {
     logger.debug('Subscribing to object actions...', id, objectType);
-    await etcdServer.onPrefixPutEvent(
-      `/${objectType}s/${id}/actions`,
+    const subject = `${objectType}s.${id}.actions`;
+
+    await natsServer.subscribe(
+      subject,
       this.socketClient.id,
-      (key, value) => {
+      (subject, value) => {
         if (!value?.result) {
           logger.trace('Object action:', id);
           this.socketClient.socket.emit(
@@ -34,9 +36,9 @@ export class ActionManager {
               action: { ...value }
             },
             result => {
-              logger.trace('Got action result:', key);
-              const actionId = key.split('/').pop();
-              etcdServer.setKey(`/${objectType}s/${id}/actions/${actionId}`, {
+              logger.trace('Got action result:', subject);
+              const actionId = value.actionId || generateEtcId();
+              natsServer.publish(`${subject}.${actionId}`, {
                 ...value,
                 result: { ...result }
               });
@@ -49,49 +51,49 @@ export class ActionManager {
   }
 
   async removeObjectActionsListener(id, objectType) {
-    await etcdServer.removePrefixWatcher(
-      `/${objectType}s/${id}/actions`,
-      this.socketClient.id,
-      'put'
-    );
+    const subject = `${objectType}s.${id}.actions`;
+    await natsServer.removeSubscription(subject, this.socketClient.id);
     return { success: true };
   }
 
   async sendObjectAction(id, objectType, action, callback) {
+    const actionId = generateEtcId();
+    const subject = `${objectType}s.${id}.actions.${actionId}`;
+
     try {
-      const actionId = generateEtcId();
       this.callbacks.set(actionId, callback);
       logger.trace(
         `Calling action id: ${actionId}, object id: ${id}, object type: ${objectType} Action:`,
         action
       );
-      await etcdServer.onKeyPutEvent(
-        `/${objectType}s/${id}/actions/${actionId}`,
+
+      // Subscribe to the response subject
+      await natsServer.subscribe(
+        subject,
         this.socketClient.socketId,
-        async (key, value) => {
+        async (subject, value) => {
           if (value.result) {
             logger.trace('Calling result callback...');
             const storedCallback = this.callbacks.get(actionId);
-            await etcdServer.removeKeyWatcher(
-              `/${objectType}s/${id}/actions/${actionId}`,
-              this.socketClient.socketId,
-              'put'
-            );
-            await etcdServer.deleteKey(
-              `/${objectType}s/${id}/actions/${actionId}`
+            await natsServer.removeSubscription(
+              subject,
+              this.socketClient.socketId
             );
             storedCallback(value.result);
           }
         }
       );
-      await etcdServer.setKey(
-        `/${objectType}s/${id}/actions/${actionId}`,
-        action
-      );
+
+      // Publish the action
+      await natsServer.publish(`${objectType}s.${id}.actions`, {
+        ...action,
+        actionId: actionId
+      });
+
       return true;
     } catch (error) {
       logger.error(
-        `Failed to set value for /${objectType}s/${id}/object:`,
+        `Failed to send action for ${objectType}s.${id}.actions.${actionId}:`,
         error
       );
       return false;

src/auth/auth.js

@@ -4,11 +4,7 @@ import jwt from 'jsonwebtoken';
 import log4js from 'log4js';
 // Load configuration
 import { loadConfig } from '../config.js';
-import {
-  editObject,
-  getObject,
-  getObjectByFilter
-} from '../database/database.js';
+import { editObject, getObject, listObjects } from '../database/database.js';
 import { hostModel } from '../database/schemas/management/host.schema.js';
 import { userModel } from '../database/schemas/management/user.schema.js';
 import { generateAuthCode } from '../utils.js';
@@ -82,16 +78,16 @@ export class KeycloakAuth {
         roles: this.extractRoles(decodedToken)
       };
 
-      const user = await getObjectByFilter({
+      const user = await listObjects({
         model: userModel,
         filter: { username: decodedUser.username }
       });
 
       // Cache the verified token
       const expiresAt = introspection.exp * 1000; // Convert to milliseconds
-      this.tokenCache.set(token, { expiresAt, user });
+      this.tokenCache.set(token, { expiresAt, user: user[0] });
 
-      return { valid: true, user };
+      return { valid: true, user: user[0] };
     } catch (error) {
       logger.error('Token verification error:', error.message);
       return { valid: false };
@@ -167,13 +163,14 @@ export class CodeAuth {
 
   async verifyOtp(otp) {
     try {
-      const host = await getObjectByFilter({
+      const hosts = await listObjects({
         model: hostModel,
         filter: { otp: otp },
         cached: false
       });
+      const host = hosts[0];
       if (host == undefined) {
-        const error = 'No host found with OTP.';
+        const error = `No host found with OTP: ${otp}`;
         logger.warn(error);
         return { valid: false, error: error };
       }
@@ -203,9 +200,10 @@ export class CodeAuth {
         id: id,
         updateData: { authCode: generateAuthCode() }
       });
+      logger.info('Host found with OTP:', otp);
       return { valid: true, host: authCodeHost };
     } catch (error) {
-      logger.error('Code verification error:', error.message);
+      logger.error('OTP verification error:', error.message);
       return { valid: false, error: error.message };
     }
   }
@@ -218,7 +216,6 @@ export function createAuthMiddleware(socketUser) {
 
     // Allow the 'authenticate' event through without checks
 
-    logger.trace('Event:', event);
     if (event === 'authenticate') {
       next();
       return;

src/database/database.js

@@ -11,6 +11,7 @@ import {
 import log4js from 'log4js';
 import { loadConfig } from '../config.js';
 import { userModel } from './schemas/management/user.schema.js';
+import { jsonToCacheKey } from '../utils.js';
 
 const config = loadConfig();
 
@@ -19,44 +20,31 @@ const cacheLogger = log4js.getLogger('Local Cache');
 logger.level = config.server.logLevel;
 cacheLogger.level = config.server.logLevel;
 
-const modelCaches = new Map();
+const objectCache = new NodeCache({
+  stdTTL: 30, // 30 sec expiration
+  checkperiod: 600, // 30 sec periodic cleanup
+  useClones: false // Don't clone objects for better performance
+});
 const listCache = new NodeCache({
   stdTTL: 30, // 30 sec expiration
   checkperiod: 600, // 30 sec periodic cleanup
   useClones: false // Don't clone objects for better performance
 });
 
-function getModelCache(model) {
-  const modelName = model.modelName;
-  const modelCache = modelCaches.get(modelName);
-  if (modelCache == undefined) {
-    logger.trace('Creating new model cache...');
-    const newModelCache = new NodeCache({
-      stdTTL: 30, // 30 sec expiration
-      checkperiod: 30, // 30 sec periodic cleanup
-      useClones: false // Don't clone objects for better performance
-    });
-    modelCaches.set(modelName, newModelCache);
-    return newModelCache;
-  }
-  logger.trace('Getting model cache...');
-  return modelCache;
-}
-
-export const retrieveObjectCache = ({ model, id }) => {
-  cacheLogger.trace('Retrieving:', {
+export const retrieveObjectCache = ({ model, id, populate = [] }) => {
+  const cacheKeyObject = {
     model: model.modelName,
-    id
-  });
-  const modelCache = getModelCache(model);
+    id,
+    populate
+  };
 
-  const cachedObject = modelCache.get(id);
+  const cacheKey = jsonToCacheKey(cacheKeyObject);
+
+  cacheLogger.trace('Retrieving:');
+  const cachedObject = objectCache.get(cacheKey);
 
   if (cachedObject == undefined) {
-    cacheLogger.trace('Miss:', {
-      model: model.modelName,
-      id
-    });
+    cacheLogger.trace('Miss:', cacheKeyObject);
     return undefined;
   }
 
@@ -68,25 +56,36 @@ export const retrieveObjectCache = ({ model, id }) => {
   return cachedObject;
 };
 
-export const retrieveObjectsCache = ({ model }) => {
-  cacheLogger.trace('Retrieving:', {
-    model: model.modelName
-  });
-  const modelCache = getModelCache(model);
+export const retrieveListCache = ({
+  model,
+  populate = [],
+  filter = {},
+  sort = '',
+  order = 'ascend',
+  project = {}
+}) => {
+  const cacheKeyObject = {
+    model: model.modelName,
+    id,
+    populate,
+    filter,
+    sort,
+    project,
+    order
+  };
 
-  const modelCacheKeys = modelCache.keys();
+  cacheLogger.trace('Retrieving:', cacheKeyObject);
 
-  const cachedList = listCache.get(model.modelName);
+  const cacheKey = jsonToCacheKey(cacheKeyObject);
 
-  if (cachedList == true) {
-    const cachedObjects = modelCacheKeys.map(key => modelCache.get(key));
+  const cachedList = listCache.get(cacheKey);
 
+  if (cachedList != undefined) {
     cacheLogger.trace('Hit:', {
-      model: model.modelName,
-      length: cachedObjects.length
+      ...cacheKeyObject,
+      length: cachedList.length
     });
-
-    return cachedObjects;
+    return cachedList;
   }
 
   cacheLogger.trace('Miss:', {
@@ -95,21 +94,23 @@ export const retrieveObjectsCache = ({ model }) => {
   return undefined;
 };
 
-export const updateObjectCache = ({ model, id, object }) => {
-  cacheLogger.trace('Updating:', {
+export const updateObjectCache = ({ model, id, object, populate = [] }) => {
+  const cacheKeyObject = {
     model: model.modelName,
-    id
-  });
-  const modelCache = getModelCache(model);
-  const cachedObject = modelCache.get(id) || {};
+    id,
+    populate
+  };
+
+  const cacheKey = jsonToCacheKey(cacheKeyObject);
+
+  cacheLogger.trace('Updating:', cacheKeyObject);
+
+  const cachedObject = objectCache.get(cacheKey) || {};
   const mergedObject = _.merge(cachedObject, object);
 
-  modelCache.set(id, mergedObject);
+  objectCache.set(cacheKey, mergedObject);
 
-  cacheLogger.trace('Updated:', {
-    model: model.modelName,
-    id
-  });
+  cacheLogger.trace('Updated:', { ...cacheKeyObject });
 
   return mergedObject;
 };
@@ -130,29 +131,39 @@ export const deleteObjectCache = ({ model, id }) => {
   return mergedObject;
 };
 
-export const updateObjectsCache = ({ model, objects }) => {
-  cacheLogger.trace('Updating:', {
+export const updateListCache = ({
+  model,
+  objects,
+  populate = [],
+  filter = {},
+  sort = '',
+  order = 'ascend',
+  project = {}
+}) => {
+  const cacheKeyObject = {
     model: model.modelName,
+    populate,
+    filter,
+    sort,
+    project,
+    order
+  };
+
+  cacheLogger.trace('Updating:', {
+    ...cacheKeyObject,
     length: objects.length
   });
-  const modelCache = getModelCache(model);
 
-  objects.forEach(object => {
-    const cachedObject = modelCache.get(object._id) || {};
+  const cacheKey = jsonToCacheKey(cacheKeyObject);
 
-    const mergedObject = _.merge(cachedObject, object);
-
-    modelCache.set(object._id, mergedObject);
-  });
-
-  listCache.set(model.modelName, true);
+  listCache.set(cacheKey, objects);
 
   cacheLogger.trace('Updated:', {
-    model: model.modelName,
+    ...cacheKeyObject,
     length: objects.length
   });
 
-  return mergedObject;
+  return objects;
 };
 
 // Reusable function to list objects with aggregation, filtering, search, sorting, and pagination
@@ -162,27 +173,29 @@ export const listObjects = async ({
   filter = {},
   sort = '',
   order = 'ascend',
-  project, // optional: override default projection
+  project = {}, // optional: override default projection
   cached = false
 }) => {
   try {
     logger.trace('Listing objects:', {
       model,
       populate,
-      page,
-      limit,
       filter,
       sort,
       order,
       project,
-      cache
+      cached
     });
 
-    var cacheKey = undefined;
-    var modelCache = getModelCache(model);
-
     if (cached == true) {
-      const objectsCache = retrieveObjectsCache({ model });
+      const objectsCache = retrieveObjectsCache({
+        model,
+        populate,
+        filter,
+        sort,
+        order,
+        project
+      });
       if (objectsCache != undefined) {
         return objectsCache;
       }
@@ -210,7 +223,7 @@ export const listObjects = async ({
     let query = model.find(filter).sort({ [sort]: sortOrder });
 
     // Handle populate (array or single value)
-    if (populate) {
+    if (populate.length > 0) {
       if (Array.isArray(populate)) {
         for (const pop of populate) {
           query = query.populate(pop);
@@ -221,7 +234,7 @@ export const listObjects = async ({
     }
 
     // Handle select (projection)
-    if (project) {
+    if (project != {}) {
       query = query.select(project);
     }
 
@@ -231,18 +244,25 @@ export const listObjects = async ({
 
     const finalResult = expandObjectIds(queryResult);
 
-    updateObjectsCache({ model, objects });
+    updateListCache({
+      model,
+      objects: finalResult,
+      populate,
+      filter,
+      sort,
+      order,
+      project
+    });
 
     logger.trace('Retreived from database:', {
       model,
       populate,
-      page,
-      limit,
       filter,
       sort,
       order,
       project,
-      cache
+      cached,
+      length: finalResult.length
     });
     return finalResult;
   } catch (error) {
@@ -252,7 +272,12 @@ export const listObjects = async ({
 };
 
 // Reusable function to get a single object by ID
-export const getObject = async ({ model, id, populate, cached = false }) => {
+export const getObject = async ({
+  model,
+  id,
+  populate = [],
+  cached = false
+}) => {
   try {
     logger.trace('Getting object:', {
       model,
@@ -261,7 +286,7 @@ export const getObject = async ({ model, id, populate, cached = false }) => {
     });
 
     if (cached == true) {
-      const cachedObject = retrieveObjectCache({ model, id });
+      const cachedObject = retrieveObjectCache({ model, id, populate });
       if (cachedObject != undefined) {
         return cachedObject;
       }
@@ -299,63 +324,14 @@ export const getObject = async ({ model, id, populate, cached = false }) => {
     updateObjectCache({
       model: model,
       id: finalResult._id.toString(),
+      populate,
       object: finalResult
     });
 
     return finalResult;
   } catch (error) {
     logger.error('An error retreiving object:', error.message);
-    return undefined;
-  }
-};
-
-// Reusable function to get a single object by ID
-export const getObjectByFilter = async ({ model, filter, populate }) => {
-  try {
-    logger.trace('Getting object:', {
-      model,
-      filter,
-      populate
-    });
-
-    let query = model.findOne(filter).lean();
-
-    // Handle populate (array or single value)
-    if (populate) {
-      if (Array.isArray(populate)) {
-        for (const pop of populate) {
-          query = query.populate(pop);
-        }
-      } else if (typeof populate === 'string' || typeof populate === 'object') {
-        query = query.populate(populate);
-      }
-    }
-    const finalResult = await query;
-
-    if (!finalResult) {
-      logger.warn('Object not found in database:', {
-        model,
-        filter,
-        populate
-      });
-      return undefined;
-    }
-
-    logger.trace('Retreived object from database:', {
-      model,
-      filter,
-      populate
-    });
-
-    updateObjectCache({
-      model: model,
-      id: finalResult._id.toString(),
-      object: finalResult
-    });
-
-    return finalResult;
-  } catch (error) {
-    logger.error('An error retreiving object:', error.message);
+    throw error;
     return undefined;
   }
 };
@@ -367,7 +343,7 @@ export const editObject = async ({
   updateData,
   owner = undefined,
   ownerType = undefined,
-  populate
+  populate = []
 }) => {
   try {
     // Determine parentType from model name

src/database/nats.js

@@ -0,0 +1,307 @@
+import { connect } from '@nats-io/transport-node';
+import log4js from 'log4js';
+import { loadConfig } from '../config.js';
+
+const config = loadConfig();
+const logger = log4js.getLogger('Nats');
+logger.level = config.server.logLevel;
+
+class NatsServer {
+  constructor() {
+    this.client = null;
+    this.subscriptions = new Map(); // subject → { subscription, callbacks }
+    this.requestHandlers = new Map(); // subject → { handler, callbacks }
+    this.queuedSubscriptions = new Map(); // subject → { subscription, callbacks, queue }
+
+    const natsConfig = config.database?.nats || config.database; // fallback for production config
+    const host = natsConfig.host || 'localhost';
+    const port = natsConfig.port || 4222;
+    this.servers = [`nats://${host}:${port}`];
+    this.textEncoder = new TextEncoder();
+    this.textDecoder = new TextDecoder();
+
+    logger.trace(`NatsServer: servers set to ${JSON.stringify(this.servers)}`);
+  }
+
+  async connect() {
+    if (!this.client) {
+      logger.info('Connecting to NATS...');
+      logger.trace(
+        `Creating NATS client with servers ${JSON.stringify(this.servers)}`
+      );
+
+      try {
+        this.client = await connect({
+          servers: this.servers,
+          reconnect: true,
+          maxReconnectAttempts: -1, // unlimited reconnects
+          reconnectTimeWait: 1000,
+          timeout: 20000
+        });
+
+        // Test connection by checking if client is connected
+        try {
+          if (this.client.isClosed()) {
+            throw new Error('NATS client connection failed');
+          }
+          logger.trace('NATS client connected successfully.');
+        } catch (error) {
+          throw error;
+        }
+      } catch (error) {
+        logger.error('Failed to connect to NATS:', error);
+        throw error;
+      }
+    } else {
+      logger.trace('NATS client already exists, skipping connection.');
+    }
+    return this.client;
+  }
+
+  async getClient() {
+    if (!this.client) {
+      logger.trace('No client found, calling connect().');
+      await this.connect();
+    }
+    return this.client;
+  }
+
+  async publish(subject, data) {
+    const client = await this.getClient();
+    const payload = typeof data === 'string' ? data : JSON.stringify(data);
+
+    try {
+      client.publish(subject, this.textEncoder.encode(payload));
+      logger.trace(`Published to subject: ${subject}, data: ${payload}`);
+      return { success: true };
+    } catch (error) {
+      logger.error(`Failed to publish to subject ${subject}:`, error);
+      throw error;
+    }
+  }
+
+  async request(subject, data, timeout = 30000) {
+    const client = await this.getClient();
+    const payload = typeof data === 'string' ? data : JSON.stringify(data);
+
+    try {
+      const response = await client.request(
+        subject,
+        this.textEncoder.encode(payload),
+        {
+          timeout: timeout
+        }
+      );
+
+      const responseData = this.textDecoder.decode(response.data);
+      logger.trace(`Request to subject: ${subject}, response: ${responseData}`);
+
+      // Try to parse as JSON, fallback to string
+      try {
+        return JSON.parse(responseData);
+      } catch {
+        return responseData;
+      }
+    } catch (error) {
+      if (error.code === 'TIMEOUT') {
+        logger.trace(`Request timeout for subject: ${subject}`);
+        return null;
+      }
+      throw error;
+    }
+  }
+
+  async subscribe(subject, owner, callback) {
+    const client = await this.getClient();
+    const subscriptionKey = subject;
+
+    if (this.subscriptions.has(subscriptionKey)) {
+      this.subscriptions.get(subscriptionKey).callbacks.set(owner, callback);
+      logger.trace(
+        `Added subscription callback for owner=${owner} on subject=${subject}`
+      );
+      return { success: true };
+    }
+
+    logger.trace(`Creating new subscription for subject: ${subject}`);
+    const subscription = client.subscribe(subject);
+    const callbacks = new Map();
+    callbacks.set(owner, callback);
+
+    (async () => {
+      for await (const msg of subscription) {
+        logger.trace(`Message received on subject: ${subject}`);
+        const data = this.textDecoder.decode(msg.data);
+        let parsedData;
+
+        try {
+          parsedData = JSON.parse(data);
+        } catch {
+          parsedData = data;
+        }
+
+        for (const [ownerId, cb] of callbacks) {
+          try {
+            cb(subject, parsedData, msg);
+          } catch (err) {
+            logger.error(
+              `Error in subscription callback for owner=${ownerId}, subject=${subject}:`,
+              err
+            );
+          }
+        }
+      }
+    })().catch(err => {
+      logger.error(`Subscription error for subject ${subject}:`, err);
+    });
+
+    this.subscriptions.set(subscriptionKey, { subscription, callbacks });
+    return { success: true };
+  }
+
+  async setRequestHandler(subject, owner, handler) {
+    const client = await this.getClient();
+    const handlerKey = subject;
+
+    if (this.requestHandlers.has(handlerKey)) {
+      this.requestHandlers.get(handlerKey).callbacks.set(owner, handler);
+      logger.trace(
+        `Added request handler for owner=${owner} on subject=${subject}`
+      );
+      return { success: true };
+    }
+
+    logger.trace(`Creating new request handler for subject: ${subject}`);
+    const subscription = client.subscribe(subject);
+    const callbacks = new Map();
+    callbacks.set(owner, handler);
+
+    (async () => {
+      for await (const msg of subscription) {
+        logger.trace(`Request received on subject: ${subject}`);
+        const data = this.textDecoder.decode(msg.data);
+        let parsedData;
+
+        try {
+          parsedData = JSON.parse(data);
+        } catch {
+          parsedData = data;
+        }
+
+        for (const [ownerId, cb] of callbacks) {
+          try {
+            const response = await cb(subject, parsedData, msg);
+            const responsePayload =
+              typeof response === 'string'
+                ? response
+                : JSON.stringify(response);
+            msg.respond(this.textEncoder.encode(responsePayload));
+          } catch (err) {
+            logger.error(
+              `Error in request handler for owner=${ownerId}, subject=${subject}:`,
+              err
+            );
+            // Send error response
+            msg.respond(
+              this.textEncoder.encode(JSON.stringify({ error: err.message }))
+            );
+          }
+        }
+      }
+    })().catch(err => {
+      logger.error(`Request handler error for subject ${subject}:`, err);
+    });
+
+    this.requestHandlers.set(handlerKey, { subscription, callbacks });
+    return { success: true };
+  }
+
+  async removeSubscription(subject, owner) {
+    const entry = this.subscriptions.get(subject);
+
+    if (!entry) {
+      logger.trace(`Subscription not found for subject: ${subject}`);
+      return false;
+    }
+
+    if (entry.callbacks.delete(owner)) {
+      logger.trace(
+        `Removed subscription callback for owner: ${owner} on subject: ${subject}`
+      );
+    } else {
+      logger.trace(
+        `No subscription callback found for owner: ${owner} on subject: ${subject}`
+      );
+    }
+
+    if (entry.callbacks.size === 0) {
+      logger.trace(`No callbacks left, stopping subscription for ${subject}`);
+      entry.subscription.unsubscribe();
+      this.subscriptions.delete(subject);
+    }
+
+    return true;
+  }
+
+  async removeRequestHandler(subject, owner) {
+    const entry = this.requestHandlers.get(subject);
+
+    if (!entry) {
+      logger.trace(`Request handler not found for subject: ${subject}`);
+      return false;
+    }
+
+    if (entry.callbacks.delete(owner)) {
+      logger.trace(
+        `Removed request handler for owner: ${owner} on subject: ${subject}`
+      );
+    } else {
+      logger.trace(
+        `No request handler found for owner: ${owner} on subject: ${subject}`
+      );
+    }
+
+    if (entry.callbacks.size === 0) {
+      logger.trace(`No handlers left, stopping request handler for ${subject}`);
+      entry.subscription.unsubscribe();
+      this.requestHandlers.delete(subject);
+    }
+
+    return true;
+  }
+
+  async disconnect() {
+    logger.info('Disconnecting from NATS...');
+
+    // Stop all subscriptions
+    for (const [subject, entry] of this.subscriptions) {
+      logger.trace(`Stopping subscription: ${subject}`);
+      entry.subscription.unsubscribe();
+    }
+    this.subscriptions.clear();
+
+    // Stop all queued subscriptions
+    for (const [key, entry] of this.queuedSubscriptions) {
+      logger.trace(`Stopping queued subscription: ${key}`);
+      entry.subscription.unsubscribe();
+    }
+    this.queuedSubscriptions.clear();
+
+    // Stop all request handlers
+    for (const [subject, entry] of this.requestHandlers) {
+      logger.trace(`Stopping request handler: ${subject}`);
+      entry.subscription.unsubscribe();
+    }
+    this.requestHandlers.clear();
+
+    if (this.client) {
+      await this.client.close();
+      this.client = null;
+      logger.info('Disconnected from NATS');
+    }
+  }
+}
+
+const natsServer = new NatsServer();
+
+export { NatsServer, natsServer };

src/database/schemas/production/printer.schema.js

@@ -16,7 +16,8 @@ const moonrakerSchema = new Schema(
 const alertSchema = new Schema(
   {
     priority: { type: String, required: true }, // order to show
-    type: { type: String, required: true } // selectFilament, error, info, message,
+    type: { type: String, required: true }, // selectFilament, error, info, message
+    message: { type: String, required: false }
   },
   { timestamps: true, _id: false }
 );

src/database/utils.js

@@ -1,6 +1,6 @@
 import { ObjectId } from 'mongodb';
 import { auditLogModel } from './schemas/management/auditlog.schema.js';
-import { etcdServer } from './etcd.js';
+import { natsServer } from './nats.js';
 
 function parseFilter(property, value) {
   if (typeof value === 'string') {
@@ -411,11 +411,11 @@ async function getAuditLogs(idOrIds) {
 }
 
 async function distributeUpdate(value, id, type) {
-  await etcdServer.setKey(`/${type}s/${id}/object`, value);
+  await natsServer.publish(`${type}s.${id}.object`, value);
 }
 
 async function distributeNew(id, type) {
-  await etcdServer.setKey(`/${type}s/new`, id);
+  await natsServer.publish(`${type}s.new`, id);
 }
 
 function flatternObjectIds(object) {

src/events/eventmanager.js

@@ -0,0 +1,71 @@
+import log4js from 'log4js';
+import { loadConfig } from '../config.js';
+import { natsServer } from '../database/nats.js';
+
+const config = loadConfig();
+
+// Setup logger
+const logger = log4js.getLogger('Event Manager');
+logger.level = config.server.logLevel;
+
+/**
+ * EventManager handles tracking object events using NATS and broadcasts event events via websockets.
+ */
+export class EventManager {
+  constructor(socketClient) {
+    this.socketClient = socketClient;
+  }
+
+  async subscribeToObjectEvent(id, objectType, eventType) {
+    logger.debug('Subscribing to object event:', eventType, id, objectType);
+    await natsServer.subscribe(
+      `${objectType}s.${id}.events.${eventType}`,
+      this.socketClient.socketId,
+      (key, value) => {
+        if (!value?.result) {
+          logger.trace('Object event detected:', id);
+          this.socketClient.socket.emit('objectEvent', {
+            _id: id,
+            objectType: objectType,
+            event: { ...value }
+          });
+        }
+      }
+    );
+    return { success: true };
+  }
+
+  async removeObjectEventsListener(id, objectType, eventType) {
+    // Remove specific event subscription for this object
+    await natsServer.removeSubscription(
+      `${objectType}s.${id}.events.${eventType}`,
+      this.socketClient.socketId
+    );
+    return { success: true };
+  }
+
+  async sendObjectEvent(id, objectType, event) {
+    const eventType = event?.type || 'unknown';
+    try {
+      logger.trace(
+        `Calling event: ${eventType}, object id: ${id}, object type: ${objectType} Event:`,
+        event
+      );
+      await natsServer.publish(
+        `${objectType}s.${id}.events.${eventType}`,
+        event
+      );
+      return { success: true };
+    } catch (error) {
+      logger.error(
+        `Failed to publish event for ${objectType}s.${id}.events.${eventType}:`,
+        error
+      );
+      return {
+        error:
+          error?.message ||
+          `Failed to publish event for ${objectType}s.${id}.events.${eventType}.`
+      };
+    }
+  }
+}

src/index.js

@@ -1,6 +1,7 @@
 import { loadConfig } from './config.js';
 import { SocketManager } from './socket/socketmanager.js';
 import { etcdServer } from './database/etcd.js';
+import { natsServer } from './database/nats.js';
 import express from 'express';
 import log4js from 'log4js';
 import http from 'http';
@@ -29,6 +30,15 @@ import { mongoServer } from './database/mongo.js';
     throw err;
   }
 
+  // Connect to NATS (await)
+  try {
+    await natsServer.connect();
+    logger.info('Connected to NATS');
+  } catch (err) {
+    logger.error('Failed to connect to NATS:', err);
+    throw err;
+  }
+
   // Connect to Mongo DB (await)
   try {
     await mongoServer.connect();

src/socket/sockethost.js

@@ -2,11 +2,12 @@ import log4js from 'log4js';
 // Load configuration
 import { loadConfig } from '../config.js';
 import { CodeAuth, createAuthMiddleware } from '../auth/auth.js';
-import { editObject, getObject } from '../database/database.js';
+import { editObject, getObject, listObjects } from '../database/database.js';
 import { hostModel } from '../database/schemas/management/host.schema.js';
 import { UpdateManager } from '../updates/updatemanager.js';
 import { ActionManager } from '../actions/actionmanager.js';
 import { getModelByName } from '../utils.js';
+import { EventManager } from '../events/eventmanager.js';
 
 const config = loadConfig();
 
@@ -23,6 +24,7 @@ export class SocketHost {
     this.socketManager = socketManager;
     this.updateManager = new UpdateManager(this);
     this.actionManager = new ActionManager(this);
+    this.eventManager = new EventManager(this);
     this.codeAuth = new CodeAuth();
     this.setupSocketEventHandlers();
   }
@@ -32,6 +34,13 @@ export class SocketHost {
     this.socket.on('authenticate', this.handleAuthenticate.bind(this));
     this.socket.on('updateHost', this.handleUpdateHost.bind(this));
     this.socket.on('getObject', this.handleGetObject.bind(this));
+    this.socket.on('editObject', this.handleEditObject.bind(this));
+    this.socket.on('listObjects', this.handleListObjects.bind(this));
+    this.socket.on(
+      'subscribeToObjectActions',
+      this.handleSubscribeToObjectActions.bind(this)
+    );
+    this.socket.on('objectEvent', this.handleObjectEventEvent.bind(this));
     this.socket.on('disconnect', this.handleDisconnect.bind(this));
   }
 
@@ -40,6 +49,23 @@ export class SocketHost {
   }
 
   async handleAuthenticate(data, callback) {
+    const setHostOnline = async verifyResult => {
+      logger.info('Host authenticated and valid.');
+      this.host = verifyResult.host;
+      this.id = this.host._id.toString();
+      this.authenticated = true;
+      await editObject({
+        model: hostModel,
+        id: this.host._id,
+        updateData: {
+          online: true,
+          state: { type: 'online' },
+          connectedAt: new Date()
+        },
+        owner: this.host,
+        ownerType: 'host'
+      });
+    };
     logger.trace('handleAuthenticateEvent');
     const id = data.id || undefined;
     const authCode = data.authCode || undefined;
@@ -49,17 +75,7 @@ export class SocketHost {
       logger.info('Authenticating host with id + authCode...');
       const verifyResult = await this.codeAuth.verifyCode(id, authCode);
       if (verifyResult.valid == true) {
-        logger.info('Host authenticated and valid.');
-        this.host = verifyResult.host;
-        this.id = this.host._id.toString();
-        this.authenticated = true;
-        await editObject({
-          model: hostModel,
-          id: this.host._id,
-          updateData: { online: true, state: { type: 'online' } },
-          owner: this.host,
-          ownerType: 'host'
-        });
+        await setHostOnline(verifyResult);
         await this.initializeHost();
       }
       callback(verifyResult);
@@ -71,8 +87,8 @@ export class SocketHost {
       const verifyResult = await this.codeAuth.verifyOtp(otp);
       if (verifyResult.valid == true) {
         logger.info('Host authenticated and valid.');
-        this.host = verifyResult.host;
-        this.authenticated = true;
+        await setHostOnline(verifyResult);
+        await this.initializeHost();
       }
       callback(verifyResult);
       return;
@@ -91,6 +107,18 @@ export class SocketHost {
     });
   }
 
+  async handleEditObject(data, callback) {
+    const object = await editObject({
+      model: getModelByName(data.objectType),
+      id: data._id,
+      updateData: data.updateData,
+      populate: data.populate,
+      owner: this.host,
+      ownerType: 'host'
+    });
+    callback(object);
+  }
+
   async handleGetObject(data, callback) {
     const object = await getObject({
       model: getModelByName(data.objectType),
@@ -101,12 +129,45 @@ export class SocketHost {
     callback(object);
   }
 
+  async handleListObjects(data, callback) {
+    const object = await listObjects({
+      model: getModelByName(data.objectType),
+      id: data._id,
+      cached: data?.cached,
+      populate: data?.populate,
+      filter: data?.filter,
+      project: data?.project,
+      sort: data?.sort,
+      order: data?.order
+    });
+    callback(object);
+  }
+
+  async handleObjectEventEvent(data) {
+    await this.eventManager.sendObjectEvent(
+      data._id,
+      data.objectType,
+      data.event
+    );
+  }
+
+  async handleSubscribeToObjectActions(data) {
+    await this.actionManager.subscribeToObjectActions(
+      data._id,
+      data.objectType
+    );
+  }
+
   async handleDisconnect() {
     if (this.authenticated) {
       await editObject({
         model: hostModel,
         id: this.host._id,
-        updateData: { online: false, state: { type: 'offline' } },
+        updateData: {
+          online: false,
+          state: { type: 'offline' },
+          connectedAt: null
+        },
         owner: this.host,
         ownerType: 'host'
       });

src/socket/socketuser.js

@@ -6,6 +6,7 @@ import { generateHostOTP } from '../utils.js';
 import { LockManager } from '../lock/lockmanager.js';
 import { UpdateManager } from '../updates/updatemanager.js';
 import { ActionManager } from '../actions/actionmanager.js';
+import { EventManager } from '../events/eventmanager.js';
 
 const config = loadConfig();
 
@@ -23,6 +24,7 @@ export class SocketUser {
     this.lockManager = new LockManager(this);
     this.updateManager = new UpdateManager(this);
     this.actionManager = new ActionManager(this);
+    this.eventManager = new EventManager(this);
     this.templateManager = socketManager.templateManager;
     this.keycloakAuth = new KeycloakAuth();
     this.setupSocketEventHandlers();
@@ -42,6 +44,22 @@ export class SocketUser {
       'subscribeToObjectUpdate',
       this.handleSubscribeToObjectUpdateEvent.bind(this)
     );
+    this.socket.on(
+      'subscribeToObjectEvent',
+      this.handleSubscribeToObjectEventEvent.bind(this)
+    );
+    this.socket.on(
+      'unsubscribeObjectTypeUpdate',
+      this.handleUnsubscribeToObjectTypeUpdateEvent.bind(this)
+    );
+    this.socket.on(
+      'unsubscribeObjectUpdate',
+      this.handleUnsubscribeToObjectUpdateEvent.bind(this)
+    );
+    this.socket.on(
+      'unsubscribeObjectEvent',
+      this.handleUnsubscribeObjectEventEvent.bind(this)
+    );
     this.socket.on(
       'previewTemplate',
       this.handlePreviewTemplateEvent.bind(this)
@@ -60,6 +78,7 @@ export class SocketUser {
       const result = await this.keycloakAuth.verifyToken(token);
       if (result.valid == true) {
         logger.info('User authenticated and valid.');
+
         this.user = result.user;
         this.id = this.user._id.toString();
         this.authenticated = true;
@@ -126,18 +145,47 @@ export class SocketUser {
   }
 
   async handleSubscribeToObjectTypeUpdateEvent(data, callback) {
-    const result = this.updateManager.subscribeToObjectNew(data.objectType);
-    callback(result);
+    await this.updateManager.subscribeToObjectNew(data.objectType);
+    await this.updateManager.subscribeToObjectDelete(data.objectType);
+    callback({ success: true });
   }
 
   async handleSubscribeToObjectUpdateEvent(data, callback) {
-    const result = this.updateManager.subscribeToObjectUpdate(
+    const result = await this.updateManager.subscribeToObjectUpdate(
       data._id,
       data.objectType
     );
     callback(result);
   }
 
+  async handleSubscribeToObjectEventEvent(data) {
+    await this.eventManager.subscribeToObjectEvent(
+      data._id,
+      data.objectType,
+      data.eventType
+    );
+  }
+
+  async handleUnsubscribeToObjectTypeUpdateEvent(data) {
+    await this.updateManager.removeObjectNewListener(data.objectType);
+    await this.updateManager.removeObjectDeleteListener(data.objectType);
+  }
+
+  async handleUnsubscribeToObjectUpdateEvent(data) {
+    await this.updateManager.removeObjectUpdateListener(
+      data._id,
+      data.objectType
+    );
+  }
+
+  async handleUnsubscribeObjectEventEvent(data) {
+    await this.eventManager.removeObjectEventsListener(
+      data._id,
+      data.objectType,
+      data.eventType
+    );
+  }
+
   async handlePreviewTemplateEvent(data, callback) {
     const result = await this.templateManager.renderTemplate(
       data._id,

src/templates/templatemanager.js

@@ -87,6 +87,15 @@ function getNodeStyles(attributes) {
   if (attributes?.shrink) {
     styles += `flex-shrink: ${attributes.shrink};`;
   }
+  if (attributes?.color) {
+    styles += `color: ${attributes.color};`;
+  }
+  if (attributes?.background) {
+    styles += `background: ${attributes.background};`;
+  }
+  if (attributes?.scale) {
+    styles += `transform: scale(${attributes.scale});`;
+  }
   return styles;
 }
 
@@ -120,24 +129,36 @@ async function transformCustomElements(content) {
       tree.match({ tag: 'Text' }, node => ({
         ...node,
         tag: 'p',
-        attrs: { class: 'documentText' }
+        attrs: { class: 'documentText', style: getNodeStyles(node.attrs) }
       })),
     tree =>
       tree.match({ tag: 'Bold' }, node => ({
         ...node,
         tag: 'strong',
-        attrs: { style: 'font-weight: bold;', class: 'documentBoldText' }
+        attrs: {
+          style: 'font-weight: bold;',
+          class: 'documentBoldText',
+          style: getNodeStyles(node.attrs)
+        }
       })),
     tree =>
       tree.match({ tag: 'Barcode' }, node => {
         return {
-          tag: 'svg',
+          tag: 'div',
+          content: [
+            {
+              tag: 'svg',
+              attrs: {
+                class: 'documentBarcode',
+                'jsbarcode-displayValue': 'false',
+                'jsbarcode-value': node.content[0],
+                'jsbarcode-format': node.attrs.format
+              }
+            }
+          ],
           attrs: {
-            class: 'documentBarcode',
-            'jsbarcode-width': node.attrs?.width,
-            'jsbarcode-height': node.attrs?.height,
-            'jsbarcode-value': node.content[0],
-            'jsbarcode-format': node.attrs.format
+            class: 'documentBarcodeContainer',
+            style: getNodeStyles(node.attrs)
           }
         };
       }),

src/updates/updatemanager.js

@@ -1,9 +1,6 @@
 import log4js from 'log4js';
 import { loadConfig } from '../config.js';
-import NodeCache from 'node-cache';
-import { etcdServer } from '../database/etcd.js';
-import { updateObjectCache } from '../database/database.js';
-
+import { natsServer } from '../database/nats.js';
 const config = loadConfig();
 
 // Setup logger
@@ -19,13 +16,28 @@ export class UpdateManager {
   }
 
   async subscribeToObjectNew(objectType) {
-    await etcdServer.onKeyPutEvent(
-      `/${objectType}s/new`,
+    await natsServer.subscribe(
+      `${objectType}s.new`,
       this.socketClient.socketId,
       (key, value) => {
         logger.trace('Object new event:', value);
         this.socketClient.socket.emit('objectNew', {
-          _id: value,
+          object: value,
+          objectType: objectType
+        });
+      }
+    );
+    return { success: true };
+  }
+
+  async subscribeToObjectDelete(objectType) {
+    await natsServer.subscribe(
+      `${objectType}s.delete`,
+      this.socketClient.socketId,
+      (key, value) => {
+        logger.trace('Object delete event:', value);
+        this.socketClient.socket.emit('objectDelete', {
+          object: value,
           objectType: objectType
         });
       }
@@ -34,8 +46,8 @@ export class UpdateManager {
   }
 
   async subscribeToObjectUpdate(id, objectType) {
-    await etcdServer.onKeyPutEvent(
-      `/${objectType}s/${id}/object`,
+    await natsServer.subscribe(
+      `${objectType}s.${id}.object`,
       this.socketClient.socketId,
       (key, value) => {
         logger.trace('Object update event:', id);
@@ -50,52 +62,26 @@ export class UpdateManager {
   }
 
   async removeObjectNewListener(objectType) {
-    await etcdServer.removeKeyWatcher(
-      `/${objectType}s/new`,
-      this.socketClient.socketId,
-      'put'
+    await natsServer.removeSubscription(
+      `${objectType}s.new`,
+      this.socketClient.socketId
+    );
+    return { success: true };
+  }
+
+  async removeObjectDeleteListener(objectType) {
+    await natsServer.removeSubscription(
+      `${objectType}s.delete`,
+      this.socketClient.socketId
     );
     return { success: true };
   }
 
   async removeObjectUpdateListener(id, objectType) {
-    await etcdServer.removeKeyWatcher(
-      `/${objectType}s/${id}/object`,
-      this.socketClient.socketId,
-      'put'
+    await natsServer.removeSubscription(
+      `${objectType}s.${id}.object`,
+      this.socketClient.socketId
     );
     return { success: true };
   }
-
-  async getObjectUpdate(id, objectType) {
-    try {
-      const objectUpdate = {
-        _id: id,
-        objectType: objectType,
-        object: await etcdServer.get(`/${objectType}s/${id}/object`)
-      };
-      logger.trace(`Returning path: /${objectType}s/${id}/object`);
-      return objectUpdate;
-    } catch (error) {
-      logger.error(
-        `UpdateManager: Failed to get current value for /${objectType}s/${id}/object:`,
-        error
-      );
-      return { error: 'Not found' };
-    }
-  }
-
-  async setObjectUpdate(id, objectType, value) {
-    try {
-      await etcdServer.set(`/${objectType}s/${id}/object`, value);
-      logger.trace(`Set value for path: /${objectType}s/${id}/object`);
-      return true;
-    } catch (error) {
-      logger.error(
-        `Failed to set value for /${objectType}s/${id}/object:`,
-        error
-      );
-      return false;
-    }
-  }
 }

src/utils.js

@@ -2,6 +2,7 @@ import { editObject } from './database/database.js';
 import { hostModel } from './database/schemas/management/host.schema.js';
 import crypto from 'crypto';
 import { nanoid } from 'nanoid';
+import canonicalize from 'canonical-json';
 
 import { loadConfig } from './config.js';
 import { userModel } from './database/schemas/management/user.schema.js';
@@ -86,5 +87,11 @@ export function getChangedValues(oldObj, newObj, old = false) {
 }
 
 export function getModelByName(modelName) {
-  return modelList.filter(model => model.modelName == modelName);
+  return modelList.filter(model => model.modelName == modelName)[0];
+}
+
+export function jsonToCacheKey(obj) {
+  const normalized = canonicalize(obj);
+  const hash = crypto.createHash('sha256').update(normalized).digest('hex');
+  return hash;
 }