# Form-Data [![NPM Module](https://img.shields.io/npm/v/form-data.svg)](https://www.npmjs.com/package/form-data) [![Join the chat at https://gitter.im/form-data/form-data](http://form-data.github.io/images/gitterbadge.svg)](https://gitter.im/form-data/form-data)

A library to create readable ```"multipart/form-data"``` streams. Can be used to submit forms and file uploads to other web applications.

The API of this library is inspired by the [XMLHttpRequest-2 FormData Interface][xhr2-fd].

[xhr2-fd]: http://dev.w3.org/2006/webapi/XMLHttpRequest-2/Overview.html#the-formdata-interface
[streams2-thing]: http://nodejs.org/api/stream.html#stream_compatibility_with_older_node_versions

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## Install

```
npm install --save form-data
```

## Usage

In this example we are constructing a form with 3 fields that contain a string,
a buffer and a file stream.

``` javascript
var FormData = require('form-data');
var fs = require('fs');

var form = new FormData();
form.append('my_field', 'my value');
form.append('my_buffer', new Buffer(10));
form.append('my_file', fs.createReadStream('/foo/bar.jpg'));
```

Also you can use http-response stream:

``` javascript
var FormData = require('form-data');
var http = require('http');

var form = new FormData();

http.request('http://nodejs.org/images/logo.png', function(response) {
  form.append('my_field', 'my value');
  form.append('my_buffer', new Buffer(10));
  form.append('my_logo', response);
});
```

Or @mikeal's [request](https://github.com/request/request) stream:

``` javascript
var FormData = require('form-data');
var request = require('request');

var form = new FormData();

form.append('my_field', 'my value');
form.append('my_buffer', new Buffer(10));
form.append('my_logo', request('http://nodejs.org/images/logo.png'));
```

In order to submit this form to a web application, call ```submit(url, [callback])``` method:

``` javascript
form.submit('http://example.org/', function(err, res) {
  // res – response object (http.IncomingMessage)  //
  res.resume();
});

```

For more advanced request manipulations ```submit()``` method returns ```http.ClientRequest``` object, or you can choose from one of the alternative submission methods.

### Alternative submission methods

You can use node's http client interface:

``` javascript
var http = require('http');

var request = http.request({
  method: 'post',
  host: 'example.org',
  path: '/upload',
  headers: form.getHeaders()
});

form.pipe(request);

request.on('response', function(res) {
  console.log(res.statusCode);
});
```

Or if you would prefer the `'Content-Length'` header to be set for you:

``` javascript
form.submit('example.org/upload', function(err, res) {
  console.log(res.statusCode);
});
```

To use custom headers and pre-known length in parts:

``` javascript
var CRLF = '\r\n';
var form = new FormData();

var options = {
  header: CRLF + '--' + form.getBoundary() + CRLF + 'X-Custom-Header: 123' + CRLF + CRLF,
  knownLength: 1
};

form.append('my_buffer', buffer, options);

form.submit('http://example.com/', function(err, res) {
  if (err) throw err;
  console.log('Done');
});
```

Form-Data can recognize and fetch all the required information from common types of streams (```fs.readStream```, ```http.response``` and ```mikeal's request```), for some other types of streams you'd need to provide "file"-related information manually:

``` javascript
someModule.stream(function(err, stdout, stderr) {
  if (err) throw err;

  var form = new FormData();

  form.append('file', stdout, {
    filename: 'unicycle.jpg',
    contentType: 'image/jpg',
    knownLength: 19806
  });

  form.submit('http://example.com/', function(err, res) {
    if (err) throw err;
    console.log('Done');
  });
});
```

For edge cases, like POST request to URL with query string or to pass HTTP auth credentials, object can be passed to `form.submit()` as first parameter:

``` javascript
form.submit({
  host: 'example.com',
  path: '/probably.php?extra=params',
  auth: 'username:password'
}, function(err, res) {
  console.log(res.statusCode);
});
```

In case you need to also send custom HTTP headers with the POST request, you can use the `headers` key in first parameter of `form.submit()`:

``` javascript
form.submit({
  host: 'example.com',
  path: '/surelynot.php',
  headers: {'x-test-header': 'test-header-value'}
}, function(err, res) {
  console.log(res.statusCode);
});
```

### Integration with other libraries

#### Request

Form submission using  [request](https://github.com/request/request):

```javascript
var formData = {
  my_field: 'my_value',
  my_file: fs.createReadStream(__dirname + '/unicycle.jpg'),
};

request.post({url:'http://service.com/upload', formData: formData}, function(err, httpResponse, body) {
  if (err) {
    return console.error('upload failed:', err);
  }
  console.log('Upload successful!  Server responded with:', body);
});
```

For more details see [request readme](https://github.com/request/request#multipartform-data-multipart-form-uploads).

#### node-fetch

You can also submit a form using [node-fetch](https://github.com/bitinn/node-fetch):

```javascript
var form = new FormData();

form.append('a', 1);

fetch('http://example.com', { method: 'POST', body: form })
    .then(function(res) {
        return res.json();
    }).then(function(json) {
        console.log(json);
    });
```

## Notes

- ```getLengthSync()``` method DOESN'T calculate length for streams, use ```knownLength``` options as workaround.
- If it feels like FormData hangs after submit, please check [Compatibility with Older Node Versions][streams2-thing]

## License

Form-Data is released under the [MIT](License) license.
