From 7af22c9da743573df36a5e2c66ded138edb6ae42 Mon Sep 17 00:00:00 2001
From: "G.Ambatte" <sean@robertson-family.nz>
Date: Sat, 26 Jul 2025 12:13:59 +1200
Subject: [PATCH] Return a basic error message when DB connection is lost

---
 server/app.js                     |  2 +
 server/middleware/dbCheck.js      | 13 +++++++
 server/middleware/dbCheck.spec.js | 63 +++++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+)
 create mode 100644 server/middleware/dbCheck.js
 create mode 100644 server/middleware/dbCheck.spec.js

diff --git a/server/app.js b/server/app.js
index 869fe6555..113f4c37d 100644
--- a/server/app.js
+++ b/server/app.js
@@ -32,6 +32,7 @@ import { splitTextStyleAndMetadata } from '../shared/helpers.js';
 
 //==== Middleware Imports ====//
 import contentNegotiation from './middleware/content-negotiation.js';
+import dbCheck from './middleware/dbCheck.js';
 import bodyParser         from 'body-parser';
 import cookieParser       from 'cookie-parser';
 import forceSSL           from './forcessl.mw.js';
@@ -49,6 +50,7 @@ const sanitizeBrew = (brew, accessType)=>{
 app.set('trust proxy', 1 /* number of proxies between user and server */);
 
 app.use('/', serveCompressedStaticAssets(`build`));
+app.use(dbCheck);
 app.use(contentNegotiation);
 app.use(bodyParser.json({ limit: '25mb' }));
 app.use(cookieParser());
diff --git a/server/middleware/dbCheck.js b/server/middleware/dbCheck.js
new file mode 100644
index 000000000..e90190517
--- /dev/null
+++ b/server/middleware/dbCheck.js
@@ -0,0 +1,13 @@
+import mongoose from 'mongoose';
+import config from '../config.js';
+
+export default (req, res, next)=>{
+	// Bypass DB checks during testing
+	if(config.get('node_env') == 'test') return next();
+
+	if(mongoose.connection.readyState == 1) return next();
+	return res.status(503).send({
+		message : 'Unable to connect to database',
+		state   : mongoose.connection.readyState
+	});
+};
diff --git a/server/middleware/dbCheck.spec.js b/server/middleware/dbCheck.spec.js
new file mode 100644
index 000000000..c4482a54a
--- /dev/null
+++ b/server/middleware/dbCheck.spec.js
@@ -0,0 +1,63 @@
+import mongoose from 'mongoose';
+import dbCheck from './dbCheck.js';
+import config from '../config.js';
+
+describe('database check middleware', ()=>{
+	let request;
+	let response;
+	let next;
+
+	beforeEach(()=>{
+		request = {
+			get : function(key) {
+				return this[key];
+			}
+		};
+		response = {
+			status : jest.fn(()=>response),
+			send   : jest.fn(()=>{})
+		};
+		next = jest.fn();
+
+		// Mock the Config module
+		jest.mock('../config.js');
+		config.get = jest.fn((param)=>{
+			// The requested key name will be reflected to the output
+			return param;
+		});
+	});
+
+	afterEach(()=>{
+		jest.clearAllMocks();
+	});
+
+	it('should return 503 if readystate != 1', ()=>{
+		const dbState = mongoose.connection.readyState;
+
+		mongoose.connection.readyState = 99;
+
+		dbCheck(request, response);
+
+		mongoose.connection.readyState = dbState;
+
+		expect(response.status).toHaveBeenLastCalledWith(503);
+		expect(response.send).toHaveBeenLastCalledWith(
+			expect.objectContaining({
+				message : 'Unable to connect to database',
+				state   : 99
+			})
+		);
+	});
+
+	it('should call next if readystate == 1', ()=>{
+		const dbState = mongoose.connection.readyState;
+
+		mongoose.connection.readyState = 1;
+
+		dbCheck(request, response, next);
+
+		mongoose.connection.readyState = dbState;
+
+		expect(next).toHaveBeenCalled();
+	});
+});