fix: resolve server 500 errors by downgrading Express v5 and making Supabase optional

- Downgrade Express from 5.2.1 to 4.21.0 to fix middleware incompatibility
- Make Supabase connection non-fatal so server starts without it
- Add 5s timeout to Supabase requests to prevent hanging
- Fix download route filename validation to accept _dkutils_ pattern

Closes #28

Author: gaureshpai

backend/index.js

@@ -26,17 +26,20 @@ const supabase = createClient(process.env.SUPABASE_URL, process.env.SUPABASE_SER
 
 /**
  * Tests the connection to Supabase Storage by attempting to get the specified bucket.
- * Logs a success message if the bucket is found, or an error message if the connection fails.
- * @throws {Error} If the connection fails
+ * Logs a success message if the bucket is found, or a warning if the connection fails.
+ * Does NOT throw - Supabase is optional for server startup.
+ * @returns {Promise<boolean>} true if connected, false otherwise
  */
 const testSupabaseConnection = async () => {
 	try {
 		const { data: bucket, error: getBucketError } = await supabase.storage.getBucket("utilityhub");
 		if (getBucketError) throw getBucketError;
 		console.log(`Supabase Storage connected!\nBucket '${bucket.name}' found.`);
+		return true;
 	} catch (error) {
-		console.error("Supabase Storage connection failed:", error.message);
-		throw error;
+		console.warn("⚠️ Supabase Storage unavailable (non-fatal):", error.message);
+		console.warn("File storage features will not work until Supabase is reachable.");
+		return false;
 	}
 };
 
@@ -151,7 +154,7 @@ app.use((err, req, res, next) => {
 
 /**
  * Starts the Express.js server and connects to MongoDB and Supabase.
- * @throws {Error} If there is an error connecting to MongoDB or Supabase.
+ * Supabase connection failure is non-fatal - server will start without it.
  */
 const startServer = async () => {
 	try {

backend/package.json

@@ -43,7 +43,7 @@
 		"cors": "^2.8.6",
 		"docx": "catalog:",
 		"dotenv": "^17.2.3",
-		"express": "^5.2.1",
+		"express": "^4.21.0",
 		"express-rate-limit": "^8.2.1",
 		"express-validator": "^7.3.1",
 		"image-type": "^5.2.0",

backend/routes/imageConverter.js

@@ -142,7 +142,9 @@ router.get("/download", async (req, res) => {
 			"merged_dkutils_",
 		];
 
-		const isAllowed = allowedPrefixes.some((prefix) => filename.startsWith(prefix));
+		const isAllowed =
+			allowedPrefixes.some((prefix) => filename.startsWith(prefix)) ||
+			filename.includes("_dkutils_");
 		if (!isAllowed || filename.includes("..")) {
 			return res.status(403).json({ msg: "Access denied." });
 		}

backend/utils/supabaseClient.js

@@ -8,6 +8,20 @@ if (!process.env.SUPABASE_URL || !process.env.SUPABASE_SERVICE_ROLE_KEY) {
 	throw new Error("Missing required Supabase environment variables");
 }
 
-const supabase = createClient(process.env.SUPABASE_URL, process.env.SUPABASE_SERVICE_ROLE_KEY);
+const SUPABASE_TIMEOUT_MS = 5000;
+
+const fetchWithTimeout = async (url, options = {}) => {
+	const controller = new AbortController();
+	const timeoutId = setTimeout(() => controller.abort(), SUPABASE_TIMEOUT_MS);
+	try {
+		return await fetch(url, { ...options, signal: controller.signal });
+	} finally {
+		clearTimeout(timeoutId);
+	}
+};
+
+const supabase = createClient(process.env.SUPABASE_URL, process.env.SUPABASE_SERVICE_ROLE_KEY, {
+	global: { fetch: fetchWithTimeout },
+});
 
 module.exports = { supabase };