1# busboy 2 3<div align="center"> 4 5[](https://github.com/fastify/busboy/actions) 6[](https://coveralls.io/r/fastify/busboy?branch=master) 7[](https://standardjs.com/) 8[](https://github.com/fastify/.github/blob/main/SECURITY.md) 9 10</div> 11 12<div align="center"> 13 14[](https://www.npmjs.com/package/@fastify/busboy) 15[](https://www.npmjs.com/package/@fastify/busboy) 16 17</div> 18 19Description 20=========== 21 22A Node.js module for parsing incoming HTML form data. 23 24This is an officially supported fork by [fastify](https://github.com/fastify/) organization of the amazing library [originally created](https://github.com/mscdex/busboy) by Brian White, 25aimed at addressing long-standing issues with it. 26 27Benchmark (Mean time for 500 Kb payload, 2000 cycles, 1000 cycle warmup): 28 29| Library | Version | Mean time in nanoseconds (less is better) | 30|-----------------------|---------|-------------------------------------------| 31| busboy | 0.3.1 | `340114` | 32| @fastify/busboy | 1.0.0 | `270984` | 33 34[Changelog](https://github.com/fastify/busboy/blob/master/CHANGELOG.md) since busboy 0.31. 35 36Requirements 37============ 38 39* [Node.js](http://nodejs.org/) 10+ 40 41 42Install 43======= 44 45 npm i @fastify/busboy 46 47 48Examples 49======== 50 51* Parsing (multipart) with default options: 52 53```javascript 54const http = require('node:http'); 55const { inspect } = require('node:util'); 56const Busboy = require('busboy'); 57 58http.createServer((req, res) => { 59 if (req.method === 'POST') { 60 const busboy = new Busboy({ headers: req.headers }); 61 busboy.on('file', (fieldname, file, filename, encoding, mimetype) => { 62 console.log(`File [${fieldname}]: filename: ${filename}, encoding: ${encoding}, mimetype: ${mimetype}`); 63 file.on('data', data => { 64 console.log(`File [${fieldname}] got ${data.length} bytes`); 65 }); 66 file.on('end', () => { 67 console.log(`File [${fieldname}] Finished`); 68 }); 69 }); 70 busboy.on('field', (fieldname, val, fieldnameTruncated, valTruncated, encoding, mimetype) => { 71 console.log(`Field [${fieldname}]: value: ${inspect(val)}`); 72 }); 73 busboy.on('finish', () => { 74 console.log('Done parsing form!'); 75 res.writeHead(303, { Connection: 'close', Location: '/' }); 76 res.end(); 77 }); 78 req.pipe(busboy); 79 } else if (req.method === 'GET') { 80 res.writeHead(200, { Connection: 'close' }); 81 res.end(`<html><head></head><body> 82 <form method="POST" enctype="multipart/form-data"> 83 <input type="text" name="textfield"><br> 84 <input type="file" name="filefield"><br> 85 <input type="submit"> 86 </form> 87 </body></html>`); 88 } 89}).listen(8000, () => { 90 console.log('Listening for requests'); 91}); 92 93// Example output, using http://nodejs.org/images/ryan-speaker.jpg as the file: 94// 95// Listening for requests 96// File [filefield]: filename: ryan-speaker.jpg, encoding: binary 97// File [filefield] got 11971 bytes 98// Field [textfield]: value: 'testing! :-)' 99// File [filefield] Finished 100// Done parsing form! 101``` 102 103* Save all incoming files to disk: 104 105```javascript 106const http = require('node:http'); 107const path = require('node:path'); 108const os = require('node:os'); 109const fs = require('node:fs'); 110 111const Busboy = require('busboy'); 112 113http.createServer(function(req, res) { 114 if (req.method === 'POST') { 115 const busboy = new Busboy({ headers: req.headers }); 116 busboy.on('file', function(fieldname, file, filename, encoding, mimetype) { 117 var saveTo = path.join(os.tmpdir(), path.basename(fieldname)); 118 file.pipe(fs.createWriteStream(saveTo)); 119 }); 120 busboy.on('finish', function() { 121 res.writeHead(200, { 'Connection': 'close' }); 122 res.end("That's all folks!"); 123 }); 124 return req.pipe(busboy); 125 } 126 res.writeHead(404); 127 res.end(); 128}).listen(8000, function() { 129 console.log('Listening for requests'); 130}); 131``` 132 133* Parsing (urlencoded) with default options: 134 135```javascript 136const http = require('node:http'); 137const { inspect } = require('node:util'); 138 139const Busboy = require('busboy'); 140 141http.createServer(function(req, res) { 142 if (req.method === 'POST') { 143 const busboy = new Busboy({ headers: req.headers }); 144 busboy.on('file', function(fieldname, file, filename, encoding, mimetype) { 145 console.log('File [' + fieldname + ']: filename: ' + filename); 146 file.on('data', function(data) { 147 console.log('File [' + fieldname + '] got ' + data.length + ' bytes'); 148 }); 149 file.on('end', function() { 150 console.log('File [' + fieldname + '] Finished'); 151 }); 152 }); 153 busboy.on('field', function(fieldname, val, fieldnameTruncated, valTruncated) { 154 console.log('Field [' + fieldname + ']: value: ' + inspect(val)); 155 }); 156 busboy.on('finish', function() { 157 console.log('Done parsing form!'); 158 res.writeHead(303, { Connection: 'close', Location: '/' }); 159 res.end(); 160 }); 161 req.pipe(busboy); 162 } else if (req.method === 'GET') { 163 res.writeHead(200, { Connection: 'close' }); 164 res.end('<html><head></head><body>\ 165 <form method="POST">\ 166 <input type="text" name="textfield"><br />\ 167 <select name="selectfield">\ 168 <option value="1">1</option>\ 169 <option value="10">10</option>\ 170 <option value="100">100</option>\ 171 <option value="9001">9001</option>\ 172 </select><br />\ 173 <input type="checkbox" name="checkfield">Node.js rules!<br />\ 174 <input type="submit">\ 175 </form>\ 176 </body></html>'); 177 } 178}).listen(8000, function() { 179 console.log('Listening for requests'); 180}); 181 182// Example output: 183// 184// Listening for requests 185// Field [textfield]: value: 'testing! :-)' 186// Field [selectfield]: value: '9001' 187// Field [checkfield]: value: 'on' 188// Done parsing form! 189``` 190 191 192API 193=== 194 195_Busboy_ is a _Writable_ stream 196 197Busboy (special) events 198----------------------- 199 200* **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. 201 * 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). 202 * 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. 203 * The property `bytesRead` informs about the number of bytes that have been read so far. 204 205* **field**(< _string_ >fieldname, < _string_ >value, < _boolean_ >fieldnameTruncated, < _boolean_ >valueTruncated, < _string_ >transferEncoding, < _string_ >mimeType) - Emitted for each new non-file field found. 206 207* **partsLimit**() - Emitted when specified `parts` limit has been reached. No more 'file' or 'field' events will be emitted. 208 209* **filesLimit**() - Emitted when specified `files` limit has been reached. No more 'file' events will be emitted. 210 211* **fieldsLimit**() - Emitted when specified `fields` limit has been reached. No more 'field' events will be emitted. 212 213 214Busboy methods 215-------------- 216 217* **(constructor)**(< _object_ >config) - Creates and returns a new Busboy instance. 218 219 * The constructor takes the following valid `config` settings: 220 221 * **headers** - _object_ - These are the HTTP headers of the incoming request, which are used by individual parsers. 222 223 * **autoDestroy** - _boolean_ - Whether this stream should automatically call .destroy() on itself after ending. (Default: false). 224 225 * **highWaterMark** - _integer_ - highWaterMark to use for this Busboy instance (Default: WritableStream default). 226 227 * **fileHwm** - _integer_ - highWaterMark to use for file streams (Default: ReadableStream default). 228 229 * **defCharset** - _string_ - Default character set to use when one isn't defined (Default: 'utf8'). 230 231 * **preservePath** - _boolean_ - If paths in the multipart 'filename' field shall be preserved. (Default: false). 232 233 * **isPartAFile** - __function__ - Use this function to override the default file detection functionality. It has following parameters: 234 235 * fieldName - __string__ The name of the field. 236 237 * contentType - __string__ The content-type of the part, e.g. `text/plain`, `image/jpeg`, `application/octet-stream` 238 239 * fileName - __string__ The name of a file supplied by the part. 240 241 (Default: `(fieldName, contentType, fileName) => (contentType === 'application/octet-stream' || fileName !== undefined)`) 242 243 * **limits** - _object_ - Various limits on incoming data. Valid properties are: 244 245 * **fieldNameSize** - _integer_ - Max field name size (in bytes) (Default: 100 bytes). 246 247 * **fieldSize** - _integer_ - Max field value size (in bytes) (Default: 1 MiB, which is 1024 x 1024 bytes). 248 249 * **fields** - _integer_ - Max number of non-file fields (Default: Infinity). 250 251 * **fileSize** - _integer_ - For multipart forms, the max file size (in bytes) (Default: Infinity). 252 253 * **files** - _integer_ - For multipart forms, the max number of file fields (Default: Infinity). 254 255 * **parts** - _integer_ - For multipart forms, the max number of parts (fields + files) (Default: Infinity). 256 257 * **headerPairs** - _integer_ - For multipart forms, the max number of header key=>value pairs to parse **Default:** 2000 258 259 * **headerSize** - _integer_ - For multipart forms, the max size of a multipart header **Default:** 81920. 260 261 * The constructor can throw errors: 262 263 * **Busboy expected an options-Object.** - Busboy expected an Object as first parameters. 264 265 * **Busboy expected an options-Object with headers-attribute.** - The first parameter is lacking of a headers-attribute. 266 267 * **Limit $limit is not a valid number** - Busboy expected the desired limit to be of type number. Busboy throws this Error to prevent a potential security issue by falling silently back to the Busboy-defaults. Potential source for this Error can be the direct use of environment variables without transforming them to the type number. 268 269 * **Unsupported Content-Type.** - The `Content-Type` isn't one Busboy can parse. 270 271 * **Missing Content-Type-header.** - The provided headers don't include `Content-Type` at all. 272
