Add Vercel serverless deployment support with serverless-http adapter

.gitignore

@@ -0,0 +1,5 @@
+node_modules/
+.env
+.DS_Store
+*.log
+.vercel

PROPOSED_CHANGE.md

@@ -0,0 +1,121 @@
+# Proposed Changes for Vercel Deployment
+
+## Summary
+This PR adds Vercel serverless adapter configuration to enable deployment of the Express/EJS blog application on Vercel's serverless platform.
+
+## Changes Made
+
+### 1. Added `api/index.js`
+- Serverless wrapper that uses `serverless-http` to adapt the Express app
+- Attempts to require the app from common locations: `../app`, `../server`, `../src/app`, `../src/server`
+- Returns helpful error message if app cannot be found
+
+### 2. Added `vercel.json`
+- Configures Node.js 18 runtime for the serverless function
+- Routes all requests to `/api/index.js` to handle client-side routing
+- Uses `@vercel/node` builder for the API route
+
+### 3. Updated `package.json`
+- Added `serverless-http@^3.0.0` dependency
+
+### 4. Added `.gitignore`
+- Excludes `node_modules`, `.env`, logs, and `.vercel` directory from git
+
+## Required Changes for Maintainers
+
+### Update: app.js has been modified
+The `app.js` file has been updated to export the app instance while maintaining local development compatibility. The changes include:
+
+1. **Mongoose connection moved to end**: The connection is now established after all middleware and routes are configured
+2. **Conditional server start**: The app only calls `listen()` when run directly (not when imported as a module)
+3. **App export**: The app is now exported for use by the serverless adapter
+
+The current structure:
+```javascript
+// ... (Express app setup, middleware, routes)
+
+// Connect to MongoDB
+mongoose
+  .connect(dbURI)
+  .then((result) => {
+    console.log("Connected to MongoDB");
+    // Only start server if not in serverless environment
+    if (require.main === module) {
+      app.listen(3000, () => {
+        console.log("Server running on port 3000");
+      });
+    }
+  })
+  .catch((err) => console.error(err));
+
+// Export the app for serverless deployment
+module.exports = app;
+```
+
+### For Local Development
+The app works the same way as before:
+```bash
+npm start  # or node app.js
+```
+
+The server will listen on port 3000 as usual.
+
+## Deployment Steps
+
+1. Merge this PR (all necessary changes are included)
+2. Run `npm install` to install `serverless-http`
+3. **IMPORTANT**: Move the MongoDB connection string to environment variables (see Security section below)
+4. Deploy or redeploy on Vercel
+5. Vercel will automatically install dependencies and run the serverless function
+
+## Security Considerations
+
+### Critical: MongoDB Connection String
+The MongoDB connection string is currently hardcoded in `app.js` with credentials exposed:
+```javascript
+const dbURI = "mongodb+srv://netninja:test1234@nodeproject.62tovra.mongodb.net/...";
+```
+
+**This is a security vulnerability and must be addressed before deployment.**
+
+To fix this:
+1. Create a `.env` file locally (already in .gitignore):
+```
+MONGODB_URI=mongodb+srv://netninja:test1234@nodeproject.62tovra.mongodb.net/NodeProject?retryWrites=true&w=majority&appName=NodeProject
+```
+
+2. Update `app.js` to use environment variable:
+```javascript
+const dbURI = process.env.MONGODB_URI || "mongodb://localhost:27017/fallback";
+```
+
+3. Add the `MONGODB_URI` environment variable in Vercel dashboard:
+   - Go to Project Settings > Environment Variables
+   - Add `MONGODB_URI` with your connection string
+   - The value will be securely stored and not exposed in your code
+
+## Environment Variables
+
+Make sure to add all required environment variables in the Vercel dashboard:
+- Go to Project Settings > Environment Variables
+- Add `MONGODB_URI` with your connection string (see Security section above)
+- Add any other environment variables your app needs
+
+**Do not commit sensitive credentials to your repository.**
+
+## Testing Locally
+
+To test locally before deploying:
+```bash
+npm install
+npm start  # Test with regular server
+# Or use Vercel CLI:
+vercel dev
+```
+
+## Notes
+
+- **Security**: The MongoDB connection string with credentials is currently hardcoded in `app.js`. This should be moved to environment variables before deployment (see Security Considerations section above).
+- Serverless functions have cold start times, so the first request after a period of inactivity may be slower.
+- Static files in the `public` directory will be served correctly through the Express middleware.
+- EJS views will work as expected since they're rendered server-side.

api/index.js

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+const serverless = require('serverless-http');
+
+// Attempt to require the Express app from common locations
+let app;
+const possiblePaths = [
+  '../app',
+  '../server',
+  '../src/app',
+  '../src/server'
+];
+
+for (const path of possiblePaths) {
+  try {
+    app = require(path);
+    console.log(`Successfully loaded app from: ${path}`);
+    break;
+  } catch (err) {
+    // Continue to next path
+  }
+}
+
+if (!app) {
+  // If no app is found, return a helpful error
+  module.exports = (req, res) => {
+    res.status(500).json({
+      error: 'Express app not found',
+      message: 'Could not locate the Express app. Please ensure your app is exported from one of: app.js, server.js, src/app.js, or src/server.js',
+      triedPaths: possiblePaths
+    });
+  };
+} else {
+  // Wrap the Express app with serverless-http
+  module.exports = serverless(app);
+}

app.js

@@ -10,11 +10,6 @@ const app = express();
 const dbURI =
   "mongodb+srv://netninja:test1234@nodeproject.62tovra.mongodb.net/NodeProject?retryWrites=true&w=majority&appName=NodeProject";
 
-mongoose
-  .connect(dbURI)
-  .then((result) => app.listen(3000))
-  .catch((err) => console.error(err));
-
 //register view engine
 app.set("view engine", "ejs");
 // app.set('views', 'myViews')//making a new folder as the ejs view
@@ -44,3 +39,20 @@ app.use("/blogs", blogRoutes);
 app.use((req, res) => {
   res.status(404).render("404", { title: "404" });
 });
+
+// Connect to MongoDB
+mongoose
+  .connect(dbURI)
+  .then((result) => {
+    console.log("Connected to MongoDB");
+    // Only start server if not in serverless environment
+    if (require.main === module) {
+      app.listen(3000, () => {
+        console.log("Server running on port 3000");
+      });
+    }
+  })
+  .catch((err) => console.error(err));
+
+// Export the app for serverless deployment
+module.exports = app;

package.json

@@ -8,7 +8,7 @@
   },
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1",
-    "start": "node server.js"
+    "start": "node app.js"
   },
   "author": "",
   "license": "ISC",
@@ -19,6 +19,7 @@
     "method-override": "^3.0.0",
     "mongodb": "^6.5.0",
     "mongoose": "^8.3.2",
-    "morgan": "^1.10.0"
+    "morgan": "^1.10.0",
+    "serverless-http": "^3.0.0"
   }
 }

vercel.json

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+{
+  "version": 2,
+  "builds": [
+    {
+      "src": "api/index.js",
+      "use": "@vercel/node",
+      "config": {
+        "runtime": "nodejs18.x"
+      }
+    }
+  ],
+  "routes": [
+    {
+      "src": "/(.*)",
+      "dest": "/api/index.js"
+    }
+  ]
+}