# Description A node.js module for parsing incoming HTML form data. Changes (breaking or otherwise) in v1.0.0 can be found [here](https://github.com/mscdex/busboy/issues/266). # Requirements * [node.js](http://nodejs.org/) -- v10.16.0 or newer # Install npm install busboy # Examples * Parsing (multipart) with default options: ```js const http = require('http'); const busboy = require('busboy'); http.createServer((req, res) => { if (req.method === 'POST') { console.log('POST request'); const bb = busboy({ headers: req.headers }); bb.on('file', (name, file, info) => { const { filename, encoding, mimeType } = info; console.log( `File [${name}]: filename: %j, encoding: %j, mimeType: %j`, filename, encoding, mimeType ); file.on('data', (data) => { console.log(`File [${name}] got ${data.length} bytes`); }).on('close', () => { console.log(`File [${name}] done`); }); }); bb.on('field', (name, val, info) => { console.log(`Field [${name}]: value: %j`, val); }); bb.on('close', () => { console.log('Done parsing form!'); res.writeHead(303, { Connection: 'close', Location: '/' }); res.end(); }); req.pipe(bb); } else if (req.method === 'GET') { res.writeHead(200, { Connection: 'close' }); res.end(` `); } }).listen(8000, () => { console.log('Listening for requests'); }); // Example output: // // Listening for requests // < ... form submitted ... > // POST request // File [filefield]: filename: "logo.jpg", encoding: "binary", mime: "image/jpeg" // File [filefield] got 11912 bytes // Field [textfield]: value: "testing! :-)" // File [filefield] done // Done parsing form! ``` * Save all incoming files to disk: ```js const { randomFillSync } = require('crypto'); const fs = require('fs'); const http = require('http'); const os = require('os'); const path = require('path'); const busboy = require('busboy'); const random = (() => { const buf = Buffer.alloc(16); return () => randomFillSync(buf).toString('hex'); })(); http.createServer((req, res) => { if (req.method === 'POST') { const bb = busboy({ headers: req.headers }); bb.on('file', (name, file, info) => { const saveTo = path.join(os.tmpdir(), `busboy-upload-${random()}`); file.pipe(fs.createWriteStream(saveTo)); }); bb.on('close', () => { res.writeHead(200, { 'Connection': 'close' }); res.end(`That's all folks!`); }); req.pipe(bb); return; } res.writeHead(404); res.end(); }).listen(8000, () => { console.log('Listening for requests'); }); ``` # API ## Exports `busboy` exports a single function: **( _function_ )**(< _object_ >config) - Creates and returns a new _Writable_ form parser stream. * Valid `config` properties: * **headers** - _object_ - These are the HTTP headers of the incoming request, which are used by individual parsers. * **highWaterMark** - _integer_ - highWaterMark to use for the parser stream. **Default:** node's _stream.Writable_ default. * **fileHwm** - _integer_ - highWaterMark to use for individual file streams. **Default:** node's _stream.Readable_ default. * **defCharset** - _string_ - Default character set to use when one isn't defined. **Default:** `'utf8'`. * **defParamCharset** - _string_ - For multipart forms, the default character set to use for values of part header parameters (e.g. filename) that are not extended parameters (that contain an explicit charset). **Default:** `'latin1'`. * **preservePath** - _boolean_ - If paths in filenames from file parts in a `'multipart/form-data'` request shall be preserved. **Default:** `false`. * **limits** - _object_ - Various limits on incoming data. Valid properties are: * **fieldNameSize** - _integer_ - Max field name size (in bytes). **Default:** `100`. * **fieldSize** - _integer_ - Max field value size (in bytes). **Default:** `1048576` (1MB). * **fields** - _integer_ - Max number of non-file fields. **Default:** `Infinity`. * **fileSize** - _integer_ - For multipart forms, the max file size (in bytes). **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 module). This function can throw exceptions if there is something wrong with the values in `config`. For example, if the Content-Type in `headers` is missing entirely, is not a supported type, or is missing the boundary for `'multipart/form-data'` requests. ## (Special) Parser stream events * **file**(< _string_ >name, < _Readable_ >stream, < _object_ >info) - Emitted for each new file found. `name` contains the form field name. `stream` is a _Readable_ stream containing the file's data. No transformations/conversions (e.g. base64 to raw binary) are done on the file's data. `info` contains the following properties: * `filename` - _string_ - If supplied, this contains the file's filename. **WARNING:** You should almost _never_ use this value as-is (especially if you are using `preservePath: true` in your `config`) as it could contain malicious input. You are better off generating your own (safe) filenames, or at the very least using a hash of the filename. * `encoding` - _string_ - The file's `'Content-Transfer-Encoding'` value. * `mimeType` - _string_ - The file's `'Content-Type'` value. **Note:** If you listen for this event, you should always consume the `stream` whether you care about its contents or not (you can simply do `stream.resume();` if you want to discard/skip the contents), otherwise the `'finish'`/`'close'` event will never fire on the busboy parser stream. However, if you aren't accepting files, you can either simply not listen for the `'file'` event at all or set `limits.files` to `0`, and any/all files will be automatically skipped (these skipped files will still count towards any configured `limits.files` and `limits.parts` limits though). **Note:** If a configured `limits.fileSize` limit was reached for a file, `stream` will both have a boolean property `truncated` set to `true` (best checked at the end of the stream) and emit a `'limit'` event to notify you when this happens. * **field**(< _string_ >name, < _string_ >value, < _object_ >info) - Emitted for each new non-file field found. `name` contains the form field name. `value` contains the string value of the field. `info` contains the following properties: * `nameTruncated` - _boolean_ - Whether `name` was truncated or not (due to a configured `limits.fieldNameSize` limit) * `valueTruncated` - _boolean_ - Whether `value` was truncated or not (due to a configured `limits.fieldSize` limit) * `encoding` - _string_ - The field's `'Content-Transfer-Encoding'` value. * `mimeType` - _string_ - The field's `'Content-Type'` value. * **partsLimit**() - Emitted when the configured `limits.parts` limit has been reached. No more `'file'` or `'field'` events will be emitted. * **filesLimit**() - Emitted when the configured `limits.files` limit has been reached. No more `'file'` events will be emitted. * **fieldsLimit**() - Emitted when the configured `limits.fields` limit has been reached. No more `'field'` events will be emitted.