The busboy npm package is a Node.js module for parsing incoming HTML form data, particularly file uploads. It is a stream-based parser that can handle multipart/form-data, which is primarily used for uploading files via HTTP.
File Upload Parsing
This code sample demonstrates how to use busboy to parse file uploads from an HTML form. When a file is received, it logs the file details and the amount of data received.
const Busboy = require('busboy');
const http = require('http');
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 ${data.length} bytes`);
}).on('end', () => {
console.log(`File [${fieldname}] Finished`);
});
});
busboy.on('finish', () => {
console.log('Done parsing form!');
res.writeHead(303, { Connection: 'close', Location: '/' });
res.end();
});
req.pipe(busboy);
} else {
res.writeHead(404);
res.end();
}
}).listen(8000, () => {
console.log('Server listening on port 8000');
});Field Parsing
This code sample shows how to use busboy to parse non-file fields from an HTML form. It logs the name and value of each field received.
const Busboy = require('busboy');
const http = require('http');
http.createServer((req, res) => {
if (req.method === 'POST') {
const busboy = new Busboy({ headers: req.headers });
busboy.on('field', (fieldname, val, fieldnameTruncated, valTruncated, encoding, mimetype) => {
console.log(`Field [${fieldname}]: value: ${val}`);
});
busboy.on('finish', () => {
res.end('Done parsing form!');
});
req.pipe(busboy);
} else {
res.writeHead(404);
res.end();
}
}).listen(8000, () => {
console.log('Server listening on port 8000');
});Formidable is an npm package similar to busboy that is used for parsing form data, especially file uploads. It is also stream-based and can handle multipart/form-data. Compared to busboy, Formidable provides a higher-level abstraction and can also handle file uploads to disk, but it might be less efficient for large file uploads due to its buffering approach.
Multiparty is another npm package for parsing multipart/form-data. Like busboy, it is stream-based and suitable for handling large file uploads. However, multiparty differs in its API and the way it handles parts of the form data, which may make it more suitable for certain use cases.
Multer is a middleware for Express.js that handles multipart/form-data, which is primarily used for uploading files. It is built on top of busboy for maximum efficiency. Unlike busboy, which is a general-purpose stream parser, multer provides a set of convenient features specifically designed for Express applications.
A node.js module for parsing incoming HTML form data.
npm install busboy
var http = require('http'),
inspect = require('util').inspect;
var Busboy = require('busboy');
http.createServer(function(req, res) {
if (req.method === 'POST') {
var busboy = new Busboy({ headers: req.headers });
busboy.on('file', function(fieldname, file, filename, encoding) {
console.log('File [' + fieldname +']: filename: ' + filename + ', encoding: ' + encoding);
file.on('data', function(data) {
console.log('File [' + fieldname +'] got ' + data.length + ' bytes');
});
file.once('end', function() {
console.log('File [' + fieldname +'] Finished');
});
});
busboy.on('field', function(fieldname, val, valTruncated, keyTruncated) {
console.log('Field [' + fieldname + ']: value: ' + inspect(val));
});
busboy.once('end', 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" enctype="multipart/form-data">\
<input type="text" name="textfield"><br />\
<input type="file" name="filefield"><br />\
<input type="submit">\
</form>\
</body>');
}
}).listen(8000, function() {
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!
multipart/form-data & saving files. Keep track of the point where the files are all properly saved to disk.http.createServer(function(req, res) {
if (req.method === 'POST') {
var infiles = 0, outfiles = 0, done = false,
busboy = new Busboy({ headers: req.headers });
console.log('Start parsing form ...');
busboy.on('file', function(fieldname, file, filename, encoding) {
++infiles;
onFile(fieldname, file, filename, encoding, function() {
++outfiles;
if (done)
console.log(outfiles + '/' + infiles + ' parts written to disk');
if (done && infiles === outfiles) {
// ACTUAL EXIT CONDITION
console.log('All parts written to disk');
res.writeHead(200, { 'Connection': 'close' });
res.end("That's all folks!");
}
});
});
busboy.once('end', function() {
console.log('Done parsing form!');
done = true;
});
req.pipe(busboy);
}
}).listen(8000, function() {
console.log('Listening for requests');
});
function onFile(fieldname, file, filename, encoding, next) {
// or save at some other location
var fstream = fs.createWriteStream(path.join(os.tmpDir(), path.basename(filename)));
file.once('end', function() {
console.log(fieldname + '(' + filename + ') EOF');
});
fstream.once('close', function() {
console.log(fieldname + '(' + filename + ') written to disk');
next();
});
console.log(fieldname + '(' + filename + ') start saving');
file.pipe(fstream);
}
var http = require('http'),
inspect = require('util').inspect;
var Busboy = require('busboy');
http.createServer(function(req, res) {
if (req.method === 'POST') {
var busboy = new Busboy({ headers: req.headers });
busboy.on('file', function(fieldname, file, filename, encoding) {
console.log('File [' + fieldname +']: filename: ' + filename + ', encoding: ' + encoding);
file.on('data', function(data) {
console.log('File [' + fieldname +'] got ' + data.length + ' bytes');
});
file.once('end', function() {
console.log('File [' + fieldname +'] Finished');
});
});
busboy.on('field', function(fieldname, val, valTruncated, keyTruncated) {
console.log('Field [' + fieldname + ']: value: ' + inspect(val));
});
busboy.once('end', 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>');
}
}).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!
Busboy is a WritableStream
file(< string >fieldname, < ReadableStream >stream, < string >filename, < string >transferEncoding) - Emitted for each new file form field found. transferEncoding contains the 'Content-Transfer-Encoding' value for the file stream.
field(< string >fieldname, < string >value, < boolean >valueTruncated, < boolean >fieldnameTruncated) - Emitted for each new non-file field found.
Note: The stream passed in on the 'file' event will also emit a 'limit' event (no arguments) if the fileSize limit is reached. If this happens, no more data will be available on the stream.
(constructor)(< object >config) - Creates and returns a new Busboy instance with the following valid config settings:
headers - object - These are the HTTP headers of the incoming request, which are used by individual parsers.
highWaterMark - integer - highWaterMark from WritableStream (Default: WritableStream default).
limits - object - Various limits on incoming data. Valid properties are:
fieldNameSize - integer - Max field name size (Default: 100 bytes).
fieldSize - integer - Max field value size (Default: 1MB).
fields - integer - Max number of non-file fields (Default: Infinity).
fileSize - integer - For multipart forms, the max file size (Default: Infinity).
files - integer - For multipart forms, the max number of file fields (Default: Infinity).
parts - integer - For multipart forms, the max number of parts (fields + files) (Default: Infinity).
headerPairs - integer - For multipart forms, the max number of header key=>value pairs to parse Default: 2000 (same as node's http).
FAQs
A streaming parser for HTML form data for node.js
The npm package busboy receives a total of 12,729,367 weekly downloads. As such, busboy popularity was classified as popular.
We found that busboy demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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