# 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
  
  [![Linux Build](https://img.shields.io/travis/form-data/form-data/master.svg?label=linux:0.10-5.x)](https://travis-ci.org/form-data/form-data)
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  [![Dependency Status](https://img.shields.io/david/form-data/form-data.svg)](https://david-dm.org/form-data/form-data)
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  ## Install
  
  ```
  npm install 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
  ';
  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 and you're on ```node-0.10```, please check [Compatibility with Older Node Versions][streams2-thing]
  
  ## License
  
  Form-Data is licensed under the MIT license.