Introduction to Busboy

Busboy is a Node.js module for handling HTML form file uploads. It is a lightweight and efficient middleware that makes file uploading in Node.js applications straightforward. In this blog post, we’ll explore Busboy and provide dozens of useful API explanations with code snippets.

Installing Busboy

  npm install busboy

Initializing Busboy

First, set up a basic Node.js server and initialize Busboy:

  const http = require('http');
  const Busboy = require('busboy');
  
  const server = http.createServer((req, res) => {
    if (req.method === 'POST') {
      const busboy = new Busboy({ headers: req.headers });
      // Busboy code will go here
    } else {
      res.writeHead(404);
      res.end();
    }
  });
  
  server.listen(8000, () => {
    console.log('Server listening on http://localhost:8000');
  });

Handling File Uploads

You can add event listeners to handle different parts of the upload:

  busboy.on('file', (fieldname, file, filename, encoding, mimetype) => {
    console.log(`File [${fieldname}]: filename: ${filename}, encoding: ${encoding}, mimetype: ${mimetype}`);
    file.on('data', (data) => {
      console.log(`File [${fieldname}] got ${data.length} bytes`);
    });
    file.on('end', () => {
      console.log(`File [${fieldname}] Finished`);
    });
  });

  busboy.on('finish', () => {
    res.writeHead(200, { 'Connection': 'close' });
    res.end("That's all folks!");
  });

  req.pipe(busboy);

Handling Form Fields

Busboy also allows you to handle regular form fields:

  busboy.on('field', (fieldname, val, fieldnameTruncated, valTruncated, encoding, mimetype) => {
    console.log(`Field [${fieldname}]: value: ${val}`);
  });

Complete App Example

Here’s a complete example of a simple file upload server:

  const http = require('http');
  const Busboy = require('busboy');
  
  const server = http.createServer((req, res) => {
    if (req.method === 'POST') {
      const busboy = new Busboy({ headers: req.headers });
      
      busboy.on('file', (fieldname, file, filename, encoding, mimetype) => {
        console.log(`File [${fieldname}]: filename: ${filename}, encoding: ${encoding}, mimetype: ${mimetype}`);
        file.on('data', (data) => {
          console.log(`File [${fieldname}] got ${data.length} bytes`);
        });
        file.on('end', () => {
          console.log(`File [${fieldname}] Finished`);
        });
      });

      busboy.on('field', (fieldname, val, fieldnameTruncated, valTruncated, encoding, mimetype) => {
        console.log(`Field [${fieldname}]: value: ${val}`);
      });

      busboy.on('finish', () => {
        res.writeHead(200, { 'Connection': 'close' });
        res.end("That's all folks!");
      });

      req.pipe(busboy);
    } else {
      res.writeHead(404);
      res.end();
    }
  });
  
  server.listen(8000, () => {
    console.log('Server listening on http://localhost:8000');
  });

By using Busboy, you can effectively handle file uploads and form data in your Node.js applications with ease.

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