HORIZON PROJECT

# multiparty [![Build Status](https://travis-ci.org/pillarjs/multiparty.svg?branch=master)](https://travis-ci.org/pillarjs/multiparty) [![Coverage Status](https://img.shields.io/coveralls/pillarjs/multiparty.svg)](https://coveralls.io/r/pillarjs/multiparty)

Parse http requests with content-type `multipart/form-data`, also known as file uploads.

See also [busboy](https://github.com/mscdex/busboy) - a

[faster](https://github.com/mscdex/dicer/wiki/Benchmarks) alternative

which may be worth looking into.

### Why the fork?

 * This module uses the Node.js v0.10 streams properly

 * It will not create a temp file for you unless you want it to.

 * Counts bytes and does math to help you figure out the `Content-Length` of

   the final part.

 * You can stream uploads to s3 with

   [aws-sdk](https://github.com/aws/aws-sdk-js), for [example](examples/s3.js).

 * Less bugs. This code is simpler, has all deprecated functionality removed,

   has cleaner tests, and does not try to do anything beyond multipart stream

   parsing.

## Installation

```

npm install multiparty

```

## Usage

 * See [examples](examples).

Parse an incoming `multipart/form-data` request.

```js

var multiparty = require('multiparty');

var http = require('http');

var util = require('util');

http.createServer(function(req, res) {

  if (req.url === '/upload' && req.method === 'POST') {

    // parse a file upload

    var form = new multiparty.Form();

    form.parse(req, function(err, fields, files) {

      res.writeHead(200, {'content-type': 'text/plain'});

      res.write('received upload:\n\n');

      res.end(util.inspect({fields: fields, files: files}));

    });

    return;

  }

  // show a file upload form

  res.writeHead(200, {'content-type': 'text/html'});

  res.end(

    '<form action="/upload" enctype="multipart/form-data" method="post">'+

    '<input type="text" name="title"><br>'+

    '<input type="file" name="upload" multiple="multiple"><br>'+

    '<input type="submit" value="Upload">'+

    '</form>'

  );

}).listen(8080);

```

## API

### multiparty.Form

```js

var form = new multiparty.Form(options)

```

Creates a new form. Options:

 * `encoding` - sets encoding for the incoming form fields. Defaults to `utf8`.

 * `maxFieldsSize` - Limits the amount of memory all fields (not files) can

   allocate in bytes. If this value is exceeded, an `error` event is emitted.

   The default size is 2MB.

 * `maxFields` - Limits the number of fields that will be parsed before

   emitting an `error` event. A file counts as a field in this case.

   Defaults to 1000.

 * `maxFilesSize` - Only relevant when `autoFiles` is `true`.  Limits the

   total bytes accepted for all files combined. If this value is exceeded,

   an `error` event is emitted. The default is `Infinity`.

 * `autoFields` - Enables `field` events and disables `part` events for fields.

   This is automatically set to `true` if you add a `field` listener.

 * `autoFiles` - Enables `file` events and disables `part` events for files.

   This is automatically set to `true` if you add a `file` listener.

 * `uploadDir` - Only relevant when `autoFiles` is `true`. The directory for

   placing file uploads in. You can move them later using `fs.rename()`.

   Defaults to `os.tmpdir()`.

#### form.parse(request, [cb])

Parses an incoming node.js `request` containing form data.This will cause

`form` to emit events based off the incoming request.

```js

var count = 0;

var form = new multiparty.Form();

// Errors may be emitted

// Note that if you are listening to 'part' events, the same error may be

// emitted from the `form` and the `part`.

form.on('error', function(err) {

  console.log('Error parsing form: ' + err.stack);

});

// Parts are emitted when parsing the form

form.on('part', function(part) {

  // You *must* act on the part by reading it

  // NOTE: if you want to ignore it, just call "part.resume()"

  if (!part.filename) {

    // filename is not defined when this is a field and not a file

    console.log('got field named ' + part.name);

    // ignore field's content

    part.resume();

  }

  if (part.filename) {

    // filename is defined when this is a file

    count++;

    console.log('got file named ' + part.name);

    // ignore file's content here

    part.resume();

  }

  part.on('error', function(err) {

    // decide what to do

  });

});

// Close emitted after form parsed

form.on('close', function() {

  console.log('Upload completed!');

  res.setHeader('text/plain');

  res.end('Received ' + count + ' files');

});

// Parse req

form.parse(req);

```

If `cb` is provided, `autoFields` and `autoFiles` are set to `true` and all

fields and files are collected and passed to the callback, removing the need to

listen to any events on `form`. This is for convenience when you want to read

everything, but be sure to write cleanup code, as this will write all uploaded

files to the disk, even ones you may not be interested in.

```js

form.parse(req, function(err, fields, files) {

  Object.keys(fields).forEach(function(name) {

    console.log('got field named ' + name);

  });

  Object.keys(files).forEach(function(name) {

    console.log('got file named ' + name);

  });

  console.log('Upload completed!');

  res.setHeader('text/plain');

  res.end('Received ' + files.length + ' files');

});

```

`fields` is an object where the property names are field names and the values

are arrays of field values.

`files` is an object where the property names are field names and the values

are arrays of file objects.

#### form.bytesReceived

The amount of bytes received for this form so far.

#### form.bytesExpected

The expected number of bytes in this form.

### Events

#### 'error' (err)

Unless you supply a callback to `form.parse`, you definitely want to handle

this event. Otherwise your server *will* crash when users submit bogus

multipart requests!

Only one 'error' event can ever be emitted, and if an 'error' event is

emitted, then 'close' will not be emitted.

If the error would correspond to a certain HTTP response code, the `err` object

will have a `statusCode` property with the value of the suggested HTTP response

code to send back.

Note that an 'error' event will be emitted both from the `form` and from the

current `part`.

#### 'part' (part)

Emitted when a part is encountered in the request. `part` is a

`ReadableStream`. It also has the following properties:

 * `headers` - the headers for this part. For example, you may be interested

   in `content-type`.

 * `name` - the field name for this part

 * `filename` - only if the part is an incoming file

 * `byteOffset` - the byte offset of this part in the request body

 * `byteCount` - assuming that this is the last part in the request,

   this is the size of this part in bytes. You could use this, for

   example, to set the `Content-Length` header if uploading to S3.

   If the part had a `Content-Length` header then that value is used

   here instead.

Parts for fields are not emitted when `autoFields` is on, and likewise parts

for files are not emitted when `autoFiles` is on.

`part` emits 'error' events! Make sure you handle them.

#### 'aborted'

Emitted when the request is aborted. This event will be followed shortly

by an `error` event. In practice you do not need to handle this event.

#### 'progress' (bytesReceived, bytesExpected)

#### 'close'

Emitted after all parts have been parsed and emitted. Not emitted if an `error`

event is emitted.

If you have `autoFiles` on, this is not fired until all the data has been

flushed to disk and the file handles have been closed.

This is typically when you would send your response.

#### 'file' (name, file)

**By default multiparty will not touch your hard drive.** But if you add this

listener, multiparty automatically sets `form.autoFiles` to `true` and will

stream uploads to disk for you. 

**The max bytes accepted per request can be specified with `maxFilesSize`.**

 * `name` - the field name for this file

 * `file` - an object with these properties:

   - `fieldName` - same as `name` - the field name for this file

   - `originalFilename` - the filename that the user reports for the file

   - `path` - the absolute path of the uploaded file on disk

   - `headers` - the HTTP headers that were sent along with this file

   - `size` - size of the file in bytes

#### 'field' (name, value)

 * `name` - field name

 * `value` - string field value