add /cluster/statushash endpoint

src/main.js

@@ -6,7 +6,7 @@ import morgan from "morgan";
 
 import { api } from "./package.js";
 import { requestPVE, handleResponse, getDiskInfo, getDeviceInfo, getNodeAvailDevices } from "./pve.js";
-import { checkAuth, approveResources, getUserResources } from "./utils.js";
+import { checkAuth, approveResources, getUserResources, getObjectHash } from "./utils.js";
 import { db, pveAPIToken, listenPort, hostname, domain } from "./db.js";
 
 const app = express();
@@ -1198,11 +1198,28 @@ app.delete(`/api/:node(${nodeRegexP})/:type(${typeRegexP})/:vmid(${vmidRegexP})/
 
 /**
  * GET - get hash of current cluster resources states
+ * Client can use this endpoint to check for cluster state changes to avoid costly data transfers to the client.
  * responses:
- * - string 
+ * - 401: {auth: false}
+ * - 200: string
  */
-app.get(`/cluster/statushash`, async (req, res) => {
-
+app.get(`/api/cluster/statushash`, async (req, res) => {
+	// check auth
+	const auth = await checkAuth(req.cookies, res);
+	if (!auth) {
+		return;
+	}
+	// get current cluster resources
+	let status = (await requestPVE("/cluster/resources", "GET", req.cookies)).data.data;
+	// filter out just state information of resources that are needed
+	let resources = ["lxc", "qemu", "node"]; 
+	let state = {};
+	status.forEach((element) => {
+		if (resources.includes(element.type)) {
+			state[element.id] = element.status;
+		}
+	});
+	res.status(200).send(getObjectHash(state));
 });
 
 app.listen(listenPort, () => {

src/utils.js

@@ -1,3 +1,5 @@
+import {createHash} from "crypto";
+
 import { getUsedResources, requestPVE } from "./pve.js";
 import { db } from "./db.js";
 
@@ -91,3 +93,10 @@ export async function approveResources (req, username, request) {
 	});
 	return approved; // if all requested resources pass, allow
 }
+
+
+export function getObjectHash (object, alg = "sha256", format = "hex") {
+	const hash = createHash(alg);
+	hash.update(JSON.stringify(object, Object.keys(object).sort()));
+	return hash.digest(format);
+}