A library to create readable ``
The API of this library is inspired by the XMLHttpRequest-2 FormData Interfacexhr2-fd.
Also you can use http-response stream:
Or @mikeal's request stream:
In order to submit this form to a web application, call ``
For more advanced request manipulations ``
List of available options could be found in combined-stream
Or if you would prefer the
To use custom headers and pre-known length in parts:
Form-Data can recognize and fetch all the required information from common types of streams (``
The
For edge cases, like POST request to URL with query string or to pass HTTP auth credentials, object can be passed to
In case you need to also send custom HTTP headers with the POST request, you can use the
You may provide a string for options, or an object.
Note: The boundary must be unique and may not appear in the data.
Note: getLengthSync doesn't calculate streams length.
For more details see request readme.
"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 Interfacexhr2-fd.
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.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:
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:
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: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.Custom options
You can provide custom options, such asmaxDataSize
:var FormData = require('form-data');
var form = new FormData({ maxDataSize: 20971520 });
form.append('my_field', 'my value');
form.append('my_buffer', /* something big */);
List of available options could be found in combined-stream
Alternative submission methods
You can use node's http client interface: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:form.submit('example.org/upload', function(err, res) {
console.log(res.statusCode);
});
To use custom headers and pre-known length in parts:
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:someModule.stream(function(err, stdout, stderr) {
if (err) throw err;
var form = new FormData();
form.append('file', stdout, {
filename: 'unicycle.jpg', // ... or:
filepath: 'photos/toys/unicycle.jpg',
contentType: 'image/jpeg',
knownLength: 19806
});
form.submit('http://example.com/', function(err, res) {
if (err) throw err;
console.log('Done');
});
});
The
filepath
property overrides filename
and may contain a relative path. This is typically used when uploading multiple files from a directory.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: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()
:form.submit({
host: 'example.com',
path: '/surelynot.php',
headers: {'x-test-header': 'test-header-value'}
}, function(err, res) {
console.log(res.statusCode);
});
Methods
- Void append( String field, Mixed value , Mixed options ).
- Headers getHeaders( Headers userHeaders )
- String getBoundary()
- Void setBoundary()
- Buffer getBuffer()
- Integer getLengthSync()
- Integer getLength( function callback )
- Boolean hasKnownLength()
- Request submit( params, function callback )
- String toString()
Void append( String field, Mixed value , Mixed options )
Append data to the form. You can submit about any format (string, integer, boolean, buffer, etc.). However, Arrays are not supported and need to be turned into strings by the user.var form = new FormData();
form.append( 'my_string', 'my value' );
form.append( 'my_integer', 1 );
form.append( 'my_boolean', true );
form.append( 'my_buffer', new Buffer(10) );
form.append( 'my_array_as_json', JSON.stringify( ['bird','cute'] ) )
You may provide a string for options, or an object.
// Set filename by providing a string for options
form.append( 'my_file', fs.createReadStream('/foo/bar.jpg'), 'bar.jpg' );
// provide an object.
form.append( 'my_file', fs.createReadStream('/foo/bar.jpg'), {filename: 'bar.jpg', contentType: 'image/jpeg', knownLength: 19806} );
Headers getHeaders( Headers userHeaders )
This method adds the correctcontent-type
header to the provided array of userHeaders
.String getBoundary()
Return the boundary of the formData. By default, the boundary consists of 26-
followed by 24 numbers
for example:
--------------------------515890814546601021194782
Void setBoundary(String boundary)
Set the boundary string, overriding the default behavior described above.Note: The boundary must be unique and may not appear in the data.
Buffer getBuffer()
Return the full formdata request package, as a Buffer. You can insert this Buffer in e.g. Axios to send multipart data.var form = new FormData();
form.append( 'my_buffer', Buffer.from([0x4a,0x42,0x20,0x52,0x6f,0x63,0x6b,0x73]) );
form.append( 'my_file', fs.readFileSync('/foo/bar.jpg') );
axios.post( 'https://example.com/path/to/api',
form.getBuffer(),
form.getHeaders()
)
Note: Because the output is of type Buffer, you can only append types that are accepted by Buffer: string, Buffer, ArrayBuffer, Array, or Array-like Object. A ReadStream for example will result in an error.Integer getLengthSync()
Same asgetLength
but synchronous.Note: getLengthSync doesn't calculate streams length.
Integer getLength( function callback )
Returns theContent-Length
async. The callback is used to handle errors and continue once the length has been calculated
this.getLength(function(err, length) {
if (err) {
this._error(err);
return;
}
// add content length
request.setHeader('Content-Length', length);
...
}.bind(this));
Boolean hasKnownLength()
Checks if the length of added values is known.Request submit( params, function callback )
Submit the form to a web application.var form = new FormData();
form.append( 'my_string', 'Hello World' );
form.submit( 'http://example.com/', function(err, res) {
// res – response object (http.IncomingMessage) //
res.resume();
} );
String toString()
Returns the form data as a string. Don't use this if you are sending files or buffers, usegetBuffer()
instead.Integration with other libraries
Request
Form submission using request: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: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);
});
axios
In Node.js you can post a file using axios:const form = new FormData();
const stream = fs.createReadStream(PATH_TO_FILE);
form.append('image', stream);
// In Node.js environment you need to set boundary in the header field 'Content-Type' by calling method `getHeaders`
const formHeaders = form.getHeaders();
axios.post('http://example.com', form, {
headers: {
...formHeaders,
},
})
.then(response => response)
.catch(error => error)
Notes
- ``
getLengthSync()
`method DOESN'T calculate length for streams, use
`knownLength
`` options as workaround. - ``
getLength(cb)
`will send an error as first parameter of callback if stream length cannot be calculated (e.g. send in custom streams w/o using
`knownLength
``). - ``
submit
`will not add
content-length` if form length is unknown or not calculable. - Starting version
2.x
FormData has dropped support fornode@0.10.x
. - Starting version
3.x
FormData has dropped support fornode@4.x
.