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 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.

$3

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);
});
`

$3

#### Request

Form submission using 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.

#### node-fetch

You can also submit a form using 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.