From 15bd2019b052f08633c6069dcbf659537f24c4b5 Mon Sep 17 00:00:00 2001
From: om-dev007 <officialomnarayan@gmail.com>
Date: Sun, 28 Jun 2026 23:03:55 +0530
Subject: [PATCH] refactor: centralize environment variable management and
 update usage across controllers and middleware

---
 backend/src/config/env.ts                 | 26 +++++++++++++++++++++++
 backend/src/controllers/authController.ts |  7 +++---
 backend/src/controllers/chatController.ts |  3 ++-
 backend/src/middleware/authMiddleware.ts  |  3 ++-
 backend/src/scripts/migrate_users.ts      |  3 ++-
 backend/src/server.ts                     | 10 +++------
 6 files changed, 39 insertions(+), 13 deletions(-)
 create mode 100644 backend/src/config/env.ts

diff --git a/backend/src/config/env.ts b/backend/src/config/env.ts
new file mode 100644
index 0000000..4c7c9f5
--- /dev/null
+++ b/backend/src/config/env.ts
@@ -0,0 +1,26 @@
+import dotenv from "dotenv";
+dotenv.config();
+
+const requiredEnv = [
+    "PORT",
+    "MONGO_URI",
+    "JWT_SECRET",
+    "GOOGLE_CLIENT_ID",
+    "CLIENT_URL",
+    "GEMINI_API_KEY"
+]
+
+requiredEnv.forEach((key) => {
+    if(!process.env[key]) {
+        throw new Error(`Missing required environment variable: ${key}`);
+    }
+})
+
+export const config = {
+    PORT: process.env.PORT,
+    MONGO_URI: process.env.MONGO_URI,
+    JWT_SECRET: process.env.JWT_SECRET,
+    GOOGLE_CLIENT_ID: process.env.GOOGLE_CLIENT_ID,
+    CLIENT_URL: process.env.CLIENT_URL,
+    GEMINI_API_KEY: process.env.GEMINI_API_KEY
+}
\ No newline at end of file
diff --git a/backend/src/controllers/authController.ts b/backend/src/controllers/authController.ts
index c91b8d0..6097a4a 100644
--- a/backend/src/controllers/authController.ts
+++ b/backend/src/controllers/authController.ts
@@ -3,12 +3,13 @@ import jwt from 'jsonwebtoken';
 import bcrypt from 'bcryptjs';
 import { prisma } from '../config/db';
 import { OAuth2Client } from 'google-auth-library';
+import { config } from '../config/env';
 
-const client = new OAuth2Client(process.env.GOOGLE_CLIENT_ID);
+const client = new OAuth2Client(config.GOOGLE_CLIENT_ID);
 
 // Generate JWT
 const generateToken = (id: string) => {
-    return jwt.sign({ id }, process.env.JWT_SECRET!, { expiresIn: '30d' });
+    return jwt.sign({ id }, config.JWT_SECRET!, { expiresIn: '30d' });
 };
 
 // @desc    Register new user
@@ -97,7 +98,7 @@ export const googleAuth = async (req: Request, res: Response) => {
     try {
         const ticket = await client.verifyIdToken({
             idToken: token,
-            audience: process.env.GOOGLE_CLIENT_ID
+            audience: config.GOOGLE_CLIENT_ID
         });
 
         const payload = ticket.getPayload();
diff --git a/backend/src/controllers/chatController.ts b/backend/src/controllers/chatController.ts
index 01f28d2..20c4d4e 100644
--- a/backend/src/controllers/chatController.ts
+++ b/backend/src/controllers/chatController.ts
@@ -1,6 +1,7 @@
 import { Request, Response } from 'express';
 import { GoogleGenerativeAI } from '@google/generative-ai';
 import { prisma } from '../config/db';
+import { config } from '../config/env';
 
 const SYSTEM_PROMPT = `You are AlgoBot, a friendly and expert AI tutor for Data Structures & Algorithms on the AlgoForge platform.
 
@@ -24,7 +25,7 @@ export const chat = async (req: Request, res: Response) => {
             return res.status(400).json({ error: 'Message is required' });
         }
 
-        const apiKey = process.env.GEMINI_API_KEY;
+        const apiKey = config.GEMINI_API_KEY;
         if (!apiKey) {
             return res.status(500).json({ error: 'Gemini API key not configured' });
         }
diff --git a/backend/src/middleware/authMiddleware.ts b/backend/src/middleware/authMiddleware.ts
index 90c0ffc..b457d17 100644
--- a/backend/src/middleware/authMiddleware.ts
+++ b/backend/src/middleware/authMiddleware.ts
@@ -1,6 +1,7 @@
 import { Request, Response, NextFunction } from 'express';
 import jwt from 'jsonwebtoken';
 import { prisma } from '../config/db';
+import { config } from '../config/env';
 
 interface JwtPayload {
     id: string;
@@ -24,7 +25,7 @@ const protect = async (req: Request, res: Response, next: NextFunction) => {
         try {
             token = req.headers.authorization.split(' ')[1];
 
-            const decoded = jwt.verify(token, process.env.JWT_SECRET!) as JwtPayload;
+            const decoded = jwt.verify(token, config.JWT_SECRET!) as JwtPayload;
 
             const user = await prisma.user.findUnique({
                 where: { id: decoded.id },
diff --git a/backend/src/scripts/migrate_users.ts b/backend/src/scripts/migrate_users.ts
index c541ca3..1fbe3d2 100644
--- a/backend/src/scripts/migrate_users.ts
+++ b/backend/src/scripts/migrate_users.ts
@@ -1,10 +1,11 @@
 import { PrismaClient } from '@prisma/client';
 import dotenv from 'dotenv';
 import path from 'path';
+import { config } from '../config/env';
 
 dotenv.config({ path: path.join(__dirname, '../../.env') });
 
-const uri = process.env.MONGO_URI as string;
+const uri = config.MONGO_URI as string;
 
 async function migrate() {
     console.log("Starting migration using Prisma engine to bypass DNS issues...");
diff --git a/backend/src/server.ts b/backend/src/server.ts
index 5c16df5..d1a7c01 100644
--- a/backend/src/server.ts
+++ b/backend/src/server.ts
@@ -4,14 +4,10 @@ import cors from 'cors';
 import connectDB from './config/db';
 
 dotenv.config();
-
-// server.ts — add before app.listen()
-if (!process.env.JWT_SECRET) {
-  throw new Error('FATAL: JWT_SECRET environment variable is not set.');
-}
+import { config } from './config/env';
 
 const app: Express = express();
-const port = process.env.PORT || 5000;
+const port = config.PORT || 5000;
 
 // Middleware
 const allowedOrigins = [
@@ -19,7 +15,7 @@ const allowedOrigins = [
     'https://algoforge-2-0.onrender.com',
     'http://localhost:5173',
     'http://localhost:3000',
-    process.env.CLIENT_URL,
+    config.CLIENT_URL,
 ].filter(Boolean) as string[];
 
 app.use(cors({