const mongoose = require(‘mongoose’);
const Grid = require(‘gridfs-stream’);
const fs = require(‘fs’);
const path = require(‘path’);

// Connect to MongoDB
mongoose.connect(‘mongodb://localhost:27017/gridfs-example’, {
useNewUrlParser: true,
useUnifiedTopology: true,
});

const conn = mongoose.connection;
Grid.mongo = mongoose.mongo;

let gfs;
conn.once(‘open’, () => {
console.log(‘MongoDB connected’);
gfs = Grid(conn.db);
gfs.collection(‘uploads’);

// Upload a file
const filePath = ‘/path/to/your/file.txt’;
const writeStream = gfs.createWriteStream({
filename: path.basename(filePath),
});
fs.createReadStream(filePath).pipe(writeStream);
writeStream.on(‘close’, (file) => {
console.log(`File ${file.filename} written to DB`);

// Retrieve the file
const filename = file.filename;
const destination = `/path/to/destination/${filename}`;
const readStream = gfs.createReadStream({ filename });
const writeStream = fs.createWriteStream(destination);
readStream.pipe(writeStream);
writeStream.on(‘close’, () => {
console.log(`File ${filename} has been written to ${destination}`);

// Delete the file
gfs.remove({ filename }, (err) => {
if (err) {
console.error(‘Error deleting file:’, err);
} else {
console.log(`File ${filename} deleted from DB`);
}
});
});
});
}