218 lines
6.3 KiB
Markdown
218 lines
6.3 KiB
Markdown
# Form-Data [](https://www.npmjs.com/package/form-data) [](https://gitter.im/form-data/form-data)
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A library to create readable ```"multipart/form-data"``` streams. Can be used to submit forms and file uploads to other web applications.
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The API of this library is inspired by the [XMLHttpRequest-2 FormData Interface][xhr2-fd].
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[xhr2-fd]: http://dev.w3.org/2006/webapi/XMLHttpRequest-2/Overview.html#the-formdata-interface
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[streams2-thing]: http://nodejs.org/api/stream.html#stream_compatibility_with_older_node_versions
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[](https://travis-ci.org/form-data/form-data)
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[](https://ci.appveyor.com/project/alexindigo/form-data)
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[](https://coveralls.io/github/form-data/form-data?branch=master)
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[](https://david-dm.org/form-data/form-data)
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[](https://www.bithound.io/github/form-data/form-data)
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## Install
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```
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npm install --save form-data
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```
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## Usage
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In this example we are constructing a form with 3 fields that contain a string,
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a buffer and a file stream.
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``` javascript
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var FormData = require('form-data');
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var fs = require('fs');
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var form = new FormData();
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form.append('my_field', 'my value');
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form.append('my_buffer', new Buffer(10));
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form.append('my_file', fs.createReadStream('/foo/bar.jpg'));
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```
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Also you can use http-response stream:
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``` javascript
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var FormData = require('form-data');
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var http = require('http');
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var form = new FormData();
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http.request('http://nodejs.org/images/logo.png', function(response) {
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form.append('my_field', 'my value');
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form.append('my_buffer', new Buffer(10));
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form.append('my_logo', response);
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});
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```
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Or @mikeal's [request](https://github.com/request/request) stream:
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``` javascript
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var FormData = require('form-data');
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var request = require('request');
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var form = new FormData();
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form.append('my_field', 'my value');
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form.append('my_buffer', new Buffer(10));
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form.append('my_logo', request('http://nodejs.org/images/logo.png'));
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```
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In order to submit this form to a web application, call ```submit(url, [callback])``` method:
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``` javascript
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form.submit('http://example.org/', function(err, res) {
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// res – response object (http.IncomingMessage) //
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res.resume();
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});
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```
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For more advanced request manipulations ```submit()``` method returns ```http.ClientRequest``` object, or you can choose from one of the alternative submission methods.
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### Alternative submission methods
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You can use node's http client interface:
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``` javascript
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var http = require('http');
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var request = http.request({
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method: 'post',
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host: 'example.org',
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path: '/upload',
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headers: form.getHeaders()
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});
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form.pipe(request);
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request.on('response', function(res) {
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console.log(res.statusCode);
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});
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```
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Or if you would prefer the `'Content-Length'` header to be set for you:
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``` javascript
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form.submit('example.org/upload', function(err, res) {
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console.log(res.statusCode);
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});
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```
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To use custom headers and pre-known length in parts:
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``` javascript
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var CRLF = '\r\n';
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var form = new FormData();
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var options = {
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header: CRLF + '--' + form.getBoundary() + CRLF + 'X-Custom-Header: 123' + CRLF + CRLF,
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knownLength: 1
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};
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form.append('my_buffer', buffer, options);
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form.submit('http://example.com/', function(err, res) {
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if (err) throw err;
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console.log('Done');
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});
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```
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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:
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``` javascript
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someModule.stream(function(err, stdout, stderr) {
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if (err) throw err;
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var form = new FormData();
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form.append('file', stdout, {
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filename: 'unicycle.jpg',
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contentType: 'image/jpg',
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knownLength: 19806
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});
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form.submit('http://example.com/', function(err, res) {
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if (err) throw err;
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console.log('Done');
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});
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});
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```
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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:
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``` javascript
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form.submit({
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host: 'example.com',
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path: '/probably.php?extra=params',
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auth: 'username:password'
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}, function(err, res) {
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console.log(res.statusCode);
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});
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```
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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()`:
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``` javascript
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form.submit({
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host: 'example.com',
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path: '/surelynot.php',
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headers: {'x-test-header': 'test-header-value'}
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}, function(err, res) {
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console.log(res.statusCode);
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});
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```
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### Integration with other libraries
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#### Request
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Form submission using [request](https://github.com/request/request):
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```javascript
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var formData = {
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my_field: 'my_value',
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my_file: fs.createReadStream(__dirname + '/unicycle.jpg'),
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};
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request.post({url:'http://service.com/upload', formData: formData}, function(err, httpResponse, body) {
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if (err) {
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return console.error('upload failed:', err);
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}
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console.log('Upload successful! Server responded with:', body);
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});
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```
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For more details see [request readme](https://github.com/request/request#multipartform-data-multipart-form-uploads).
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#### node-fetch
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You can also submit a form using [node-fetch](https://github.com/bitinn/node-fetch):
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```javascript
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var form = new FormData();
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form.append('a', 1);
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fetch('http://example.com', { method: 'POST', body: form })
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.then(function(res) {
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return res.json();
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}).then(function(json) {
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console.log(json);
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});
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```
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## Notes
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- ```getLengthSync()``` method DOESN'T calculate length for streams, use ```knownLength``` options as workaround.
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- If it feels like FormData hangs after submit, please check [Compatibility with Older Node Versions][streams2-thing]
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## License
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Form-Data is released under the [MIT](License) license.
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