updated server logic

server.js

@@ -1,18 +1,19 @@
 const express = require('express');
 const multer = require('multer');
 const cors = require('cors');
-const imageProcessor = require('./image-processing-logic'); 
+const imageProcessor = require('./image-processing-logic');
 
 const app = express();
 const PORT = process.env.PORT || 7860;
 
+// Enable CORS for all origins. This is crucial for a public API.
 app.use(cors());
 app.use(express.json());
 
 const storage = multer.memoryStorage();
-const upload = multer({ 
+const upload = multer({
     storage: storage,
-    limits: { fileSize: 15 * 1024 * 1024 },
+    limits: { fileSize: 15 * 1024 * 1024 }, // 15MB file size limit
     fileFilter: (req, file, cb) => {
         if (file.mimetype.startsWith('image/')) {
             cb(null, true);
@@ -22,11 +23,18 @@ const upload = multer({
     }
 });
 
+// A simple endpoint to confirm the server is running.
 app.get('/ping', (req, res) => {
     res.status(200).send('pong');
 });
 
-app.post('/api/process', upload.single('images'), async (req, res) => {
+// A root path to prevent "Cannot GET /" errors.
+app.get('/', (req, res) => {
+    res.status(200).send('Image compression backend is running!');
+});
+
+// Main image processing route
+app.post('/api/process', upload.single('images'), async (req, res, next) => {
     try {
         if (!req.file) {
             return res.status(400).json({ error: 'No images uploaded' });
@@ -43,17 +51,32 @@ app.post('/api/process', upload.single('images'), async (req, res) => {
         
         res.setHeader('Content-Type', `image/${format}`);
         res.setHeader('Content-Disposition', `attachment; filename=compressed_${req.file.originalname}`);
-        res.send(processedImage.buffer);
+        res.status(200).send(processedImage.buffer);
 
     } catch (error) {
-        console.error('Error in compression route:', error);
-        res.status(500).json({ error: error.message });
+        // Pass any caught errors to the main error handler
+        next(error);
     }
 });
 
+// Global error handling middleware.
+// This handles all errors from the application, including Multer errors.
 app.use((err, req, res, next) => {
+    // Check for specific Multer errors
+    if (err instanceof multer.MulterError) {
+        if (err.code === 'LIMIT_FILE_SIZE') {
+            return res.status(413).json({ error: 'File is too large. Max size is 15MB.' });
+        }
+    }
+
+    // Handle other custom errors from the fileFilter or general route logic
+    if (err.message === 'Only image files are allowed!') {
+        return res.status(415).json({ error: err.message });
+    }
+
+    // Default error handling for any other unhandled errors
     console.error(err.stack);
-    res.status(500).json({ error: err.message });
+    res.status(500).json({ error: 'An unexpected error occurred.' });
 });
 
 app.listen(PORT, () => {