How to upload file in cloudinary using express.js and multer

Step-by-Step Procedure to Upload Any File in Backend using Express.js, Cloudinary, and Multer

1. Install all the packages:

   npm install express multer cloudinary dotenv

2. Create an account in Cloudinary and keep these information in a .env file:

   // Cloudinary configuration
   CLOUDINARY_CLOUD_NAME=Your_cloudinary_name
   CLOUDINARY_API_KEY=Your_cloudinary_api_key
   CLOUDINARY_API_SECRET=Your_cloudinary_secret_key

3. After installing these packages, create two files: index.js and multer-config.js.
4. In multer-config.js file, write the basic multer configuration code:

   const multer = require('multer');
   const storage = multer.memoryStorage();  // store image in memory
   const upload = multer({ storage: storage });
   module.exports = upload;

5. Use the multer mechanism in index.js file with a POST route '/upload':

   const express = require('express');
   const cloudinary = require('cloudinary').v2;
   require('dotenv').config();
   const upload = require('./multer-config');
   
   const app = express();
   
   app.use(express.json());
   app.use(express.urlencoded({ extended: true }));
   
   // Cloudinary configuration
   cloudinary.config({
       cloud_name: process.env.CLOUDINARY_CLOUD_NAME,
       api_key: process.env.CLOUDINARY_API_KEY,
       api_secret: process.env.CLOUDINARY_API_SECRET,
   });
   
   app.post('/upload', upload.single('image'), (req, res) => {
       try {
           // Upload image to Cloudinary using stream
           const uploadStream = cloudinary.uploader.upload_stream({ folder: 'upload' }, (error, result) => {
               if (error) {
                   console.error(error);
                   return res.status(500).json({ error: 'Error uploading image to Cloudinary' });
               }
               // Send the Cloudinary URL in the response
               res.json({ imageUrl: result.secure_url });
           });
   
           // Pipe the file buffer to the uploadStream
           if (req.file && req.file.buffer) {
               uploadStream.end(req.file.buffer);
           } else {
               res.status(400).json({ error: 'No file uploaded' });
           }
       } catch (error) {
           console.error(error);
           res.status(500).json({ error: 'Error processing upload' });
       }
   });
   
   //Run server
   app.listen(5000, () => {
       console.log('Server is running on port 5000');
   });

6. Now, you can hit the '/upload' route with a POST request and upload your file.

Congratulations ☺️✌️