README.md
1# Description
2
3A node.js module for parsing incoming HTML form data.
4
5Changes (breaking or otherwise) in v1.0.0 can be found [here](https://github.com/mscdex/busboy/issues/266).
6
7# Requirements
8
9* [node.js](http://nodejs.org/) -- v10.16.0 or newer
10
11
12# Install
13
14 npm install busboy
15
16
17# Examples
18
19* Parsing (multipart) with default options:
20
21```js
22const http = require('http');
23
24const busboy = require('busboy');
25
26http.createServer((req, res) => {
27 if (req.method === 'POST') {
28 console.log('POST request');
29 const bb = busboy({ headers: req.headers });
30 bb.on('file', (name, file, info) => {
31 const { filename, encoding, mimeType } = info;
32 console.log(
33 `File [${name}]: filename: %j, encoding: %j, mimeType: %j`,
34 filename,
35 encoding,
36 mimeType
37 );
38 file.on('data', (data) => {
39 console.log(`File [${name}] got ${data.length} bytes`);
40 }).on('close', () => {
41 console.log(`File [${name}] done`);
42 });
43 });
44 bb.on('field', (name, val, info) => {
45 console.log(`Field [${name}]: value: %j`, val);
46 });
47 bb.on('close', () => {
48 console.log('Done parsing form!');
49 res.writeHead(303, { Connection: 'close', Location: '/' });
50 res.end();
51 });
52 req.pipe(bb);
53 } else if (req.method === 'GET') {
54 res.writeHead(200, { Connection: 'close' });
55 res.end(`
56 <html>
57 <head></head>
58 <body>
59 <form method="POST" enctype="multipart/form-data">
60 <input type="file" name="filefield"><br />
61 <input type="text" name="textfield"><br />
62 <input type="submit">
63 </form>
64 </body>
65 </html>
66 `);
67 }
68}).listen(8000, () => {
69 console.log('Listening for requests');
70});
71
72// Example output:
73//
74// Listening for requests
75// < ... form submitted ... >
76// POST request
77// File [filefield]: filename: "logo.jpg", encoding: "binary", mime: "image/jpeg"
78// File [filefield] got 11912 bytes
79// Field [textfield]: value: "testing! :-)"
80// File [filefield] done
81// Done parsing form!
82```
83
84* Save all incoming files to disk:
85
86```js
87const { randomFillSync } = require('crypto');
88const fs = require('fs');
89const http = require('http');
90const os = require('os');
91const path = require('path');
92
93const busboy = require('busboy');
94
95const random = (() => {
96 const buf = Buffer.alloc(16);
97 return () => randomFillSync(buf).toString('hex');
98})();
99
100http.createServer((req, res) => {
101 if (req.method === 'POST') {
102 const bb = busboy({ headers: req.headers });
103 bb.on('file', (name, file, info) => {
104 const saveTo = path.join(os.tmpdir(), `busboy-upload-${random()}`);
105 file.pipe(fs.createWriteStream(saveTo));
106 });
107 bb.on('close', () => {
108 res.writeHead(200, { 'Connection': 'close' });
109 res.end(`That's all folks!`);
110 });
111 req.pipe(bb);
112 return;
113 }
114 res.writeHead(404);
115 res.end();
116}).listen(8000, () => {
117 console.log('Listening for requests');
118});
119```
120
121
122# API
123
124## Exports
125
126`busboy` exports a single function:
127
128**( _function_ )**(< _object_ >config) - Creates and returns a new _Writable_ form parser stream.
129
130* Valid `config` properties:
131
132 * **headers** - _object_ - These are the HTTP headers of the incoming request, which are used by individual parsers.
133
134 * **highWaterMark** - _integer_ - highWaterMark to use for the parser stream. **Default:** node's _stream.Writable_ default.
135
136 * **fileHwm** - _integer_ - highWaterMark to use for individual file streams. **Default:** node's _stream.Readable_ default.
137
138 * **defCharset** - _string_ - Default character set to use when one isn't defined. **Default:** `'utf8'`.
139
140 * **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'`.
141
142 * **preservePath** - _boolean_ - If paths in filenames from file parts in a `'multipart/form-data'` request shall be preserved. **Default:** `false`.
143
144 * **limits** - _object_ - Various limits on incoming data. Valid properties are:
145
146 * **fieldNameSize** - _integer_ - Max field name size (in bytes). **Default:** `100`.
147
148 * **fieldSize** - _integer_ - Max field value size (in bytes). **Default:** `1048576` (1MB).
149
150 * **fields** - _integer_ - Max number of non-file fields. **Default:** `Infinity`.
151
152 * **fileSize** - _integer_ - For multipart forms, the max file size (in bytes). **Default:** `Infinity`.
153
154 * **files** - _integer_ - For multipart forms, the max number of file fields. **Default:** `Infinity`.
155
156 * **parts** - _integer_ - For multipart forms, the max number of parts (fields + files). **Default:** `Infinity`.
157
158 * **headerPairs** - _integer_ - For multipart forms, the max number of header key-value pairs to parse. **Default:** `2000` (same as node's http module).
159
160This 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.
161
162## (Special) Parser stream events
163
164* **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:
165
166 * `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.
167
168 * `encoding` - _string_ - The file's `'Content-Transfer-Encoding'` value.
169
170 * `mimeType` - _string_ - The file's `'Content-Type'` value.
171
172 **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.
173 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).
174
175 **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.
176
177* **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:
178
179 * `nameTruncated` - _boolean_ - Whether `name` was truncated or not (due to a configured `limits.fieldNameSize` limit)
180
181 * `valueTruncated` - _boolean_ - Whether `value` was truncated or not (due to a configured `limits.fieldSize` limit)
182
183 * `encoding` - _string_ - The field's `'Content-Transfer-Encoding'` value.
184
185 * `mimeType` - _string_ - The field's `'Content-Type'` value.
186
187* **partsLimit**() - Emitted when the configured `limits.parts` limit has been reached. No more `'file'` or `'field'` events will be emitted.
188
189* **filesLimit**() - Emitted when the configured `limits.files` limit has been reached. No more `'file'` events will be emitted.
190
191* **fieldsLimit**() - Emitted when the configured `limits.fields` limit has been reached. No more `'field'` events will be emitted.
192
