busboy
Description
A Node.js module for parsing incoming HTML form data.
This is an officially supported fork by fastify organization of the amazing library originally created by Brian White,
aimed at addressing long-standing issues with it.
Benchmark (Mean time for 500 Kb payload, 2000 cycles, 1000 cycle warmup):
| Library | Version | Mean time in nanoseconds (less is better) |
|---|
| busboy | 0.3.1 | 340114 |
| @fastify/busboy | 1.0.0 | 270984 |
Changelog since busboy 0.31.
Requirements
Install
npm i @fastify/busboy
Examples
- Parsing (multipart) with default options:
const http = require('node:http');
const { inspect } = require('node:util');
const Busboy = require('@fastify/busboy');
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: ${inspect(val)}`);
});
busboy.on('finish', () => {
console.log('Done parsing form!');
res.writeHead(303, { Connection: 'close', Location: '/' });
res.end();
});
req.pipe(busboy);
} else if (req.method === 'GET') {
res.writeHead(200, { Connection: 'close' });
res.end(`<html><head></head><body>
<form method="POST" enctype="multipart/form-data">
<input type="text" name="textfield"><br>
<input type="file" name="filefield"><br>
<input type="submit">
</form>
</body></html>`);
}
}).listen(8000, () => {
console.log('Listening for requests');
});
// Example output, using http://nodejs.org/images/ryan-speaker.jpg as the file:
//
// Listening for requests
// File [filefield]: filename: ryan-speaker.jpg, encoding: binary
// File [filefield] got 11971 bytes
// Field [textfield]: value: 'testing! :-)'
// File [filefield] Finished
// Done parsing form!
- Save all incoming files to disk:
const http = require('node:http');
const path = require('node:path');
const os = require('node:os');
const fs = require('node:fs');
const Busboy = require('@fastify/busboy');
http.createServer(function(req, res) {
if (req.method === 'POST') {
const busboy = new Busboy({ headers: req.headers });
busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
var saveTo = path.join(os.tmpdir(), path.basename(fieldname));
file.pipe(fs.createWriteStream(saveTo));
});
busboy.on('finish', function() {
res.writeHead(200, { 'Connection': 'close' });
res.end("That's all folks!");
});
return req.pipe(busboy);
}
res.writeHead(404);
res.end();
}).listen(8000, function() {
console.log('Listening for requests');
});
- Parsing (urlencoded) with default options:
const http = require('node:http');
const { inspect } = require('node:util');
const Busboy = require('@fastify/busboy');
http.createServer(function(req, res) {
if (req.method === 'POST') {
const busboy = new Busboy({ headers: req.headers });
busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
console.log('File [' + fieldname + ']: filename: ' + filename);
file.on('data', function(data) {
console.log('File [' + fieldname + '] got ' + data.length + ' bytes');
});
file.on('end', function() {
console.log('File [' + fieldname + '] Finished');
});
});
busboy.on('field', function(fieldname, val, fieldnameTruncated, valTruncated) {
console.log('Field [' + fieldname + ']: value: ' + inspect(val));
});
busboy.on('finish', function() {
console.log('Done parsing form!');
res.writeHead(303, { Connection: 'close', Location: '/' });
res.end();
});
req.pipe(busboy);
} else if (req.method === 'GET') {
res.writeHead(200, { Connection: 'close' });
res.end('<html><head></head><body>\
<form method="POST">\
<input type="text" name="textfield"><br />\
<select name="selectfield">\
<option value="1">1</option>\
<option value="10">10</option>\
<option value="100">100</option>\
<option value="9001">9001</option>\
</select><br />\
<input type="checkbox" name="checkfield">Node.js rules!<br />\
<input type="submit">\
</form>\
</body></html>');
}
}).listen(8000, function() {
console.log('Listening for requests');
});
// Example output:
//
// Listening for requests
// Field [textfield]: value: 'testing! :-)'
// Field [selectfield]: value: '9001'
// Field [checkfield]: value: 'on'
// Done parsing form!
API
Busboy is a Writable stream
Busboy (special) events
-
file(< string >fieldname, < ReadableStream >stream, < string >filename, < string >transferEncoding, < string >mimeType) - Emitted for each new file form field found. transferEncoding contains the 'Content-Transfer-Encoding' value for the file stream. mimeType contains the 'Content-Type' value for the file stream.
- Note: if you listen for this event, you should always handle the
stream no matter if you care about the file contents or not (e.g. you can simply just do stream.resume(); if you want to discard the contents), otherwise the 'finish' event will never fire on the Busboy instance. However, if you don't care about any incoming files, you can simply not listen for the 'file' event at all and any/all files will be automatically and safely discarded (these discarded files do still count towards files and parts limits).
- If a configured file size limit was reached,
stream will both have a boolean property truncated (best checked at the end of the stream) and emit a 'limit' event to notify you when this happens.
- The property
bytesRead informs about the number of bytes that have been read so far.
-
field(< string >fieldname, < string >value, < boolean >fieldnameTruncated, < boolean >valueTruncated, < string >transferEncoding, < string >mimeType) - Emitted for each new non-file field found.
-
partsLimit() - Emitted when specified parts limit has been reached. No more 'file' or 'field' events will be emitted.
-
filesLimit() - Emitted when specified files limit has been reached. No more 'file' events will be emitted.
-
fieldsLimit() - Emitted when specified fields limit has been reached. No more 'field' events will be emitted.
Busboy methods
