# formidable [![npm version][npmv-img]][npmv-url] [![MIT license][license-img]][license-url] [![Libera Manifesto][libera-manifesto-img]][libera-manifesto-url]
> A Node.js module for parsing form data, especially file uploads.
### Important Notes
For more info, check the [CHANGELOG](https://github.com/node-formidable/formidable/blob/master/CHANGELOG.md) on the master branch.
#### v1 is deprecated
All `v1` versions are deprecated in NPM for over 2 years. You can find it at `formidable@v1` or `formidable@legacy` on NPM, and on [v1-legacy branch][v1branch] on GitHub.
We highly recommend to use `v2` or `v3`. Both are already in use by many, especially `v2` which was on `formidable@canary` for 2 years.
- **Status: Not Maintained!**
- We won't provide support or accept reports on that version.
- **No Backporting:** bugfixes, security fixes, or new features WILL NOT happen!
- Please move to at least **v2**!
- Try with installing `formidable@v2` and if still have the problem - report!
---
#### v2 is the new `latest`
The `v2` will be simultaneously on two places for some time - `formidable@latest` and `formidable@v2`.
The source code be available **only** on [v2 branch][v2branch].
If you want to use v2, it's recommended to use the v2 dist-tag `formidable@v2`.
**Main Differences from v1:**
- Better organization and modernized code, requiring newer Node.js versions (>= v10).
- A lot of bugfixes, closed issues, merged or closed PRs.
- **Backward compatible to v1!** Should not have problems, the major version bump is just for ensurance.
- Better docs, new features (plugins, parsers, options) and optimizations.
---
#### v3 - ESModules, Promises, Monorepo structure
We recommend to use `formidable@v3`, as it uses more modern Node.js Streams, has support for Promises and more stuff.
You can see more info and track some ideas on [issue#635](https://github.com/node-formidable/formidable/issues/635).
- The source code can be found on the [master branch](https://github.com/node-formidable/formidable) on GitHub.
- It will be published on `formidable@latest` after some time.
- Dropping older Node.js versions, requiring higher than v12-v14.
- Dropping v1 compatibility.
- Rewritten to ESModules, more optimizations.
- Moving to monorepo structure, more plugins & helper utils.
[v1branch]: https://github.com/node-formidable/formidable/tree/v1-legacy
[v2branch]: https://github.com/node-formidable/formidable/tree/v2
[v3branch]: https://github.com/node-formidable/formidable/tree/v3
---
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If you have any _how-to_ kind of questions, please read the [Contributing
Guide][contributing-url] and [Code of Conduct][code_of_conduct-url]
documents.
For bugs reports and feature requests, [please create an
issue][open-issue-url] or ping [@tunnckoCore](https://twitter.com/tunnckoCore)
at Twitter.
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## v1 status: not maintained!
## Project Status: Maintained
This module was initially developed by
[**@felixge**](https://github.com/felixge) for
[Transloadit](http://transloadit.com/), a service focused on uploading and
encoding images and videos. It has been battle-tested against hundreds of GBs of
file uploads from a large variety of clients and is considered production-ready
and is used in production for years.
Currently, we are few maintainers trying to deal with it. :) More contributors
are always welcome! :heart: Jump on
[issue #412](https://github.com/felixge/node-formidable/issues/412) which is
closed, but if you are interested we can discuss it and add you after strict
rules, like enabling Two-Factor Auth in your npm and GitHub accounts.
## Features
* Fast (~500mb/sec), non-buffering multipart parser
* Automatically writing file uploads to disk
* Low memory footprint
* Graceful error handling
* Very high test coverage
## Installation
```sh
npm install formidable@v1
npm install formidable@v2
npm install formidable@v3
```
This is a low-level package, and if you're using a high-level framework it may already be included. However, [Express v4](http://expressjs.com) does not include any multipart handling, nor does [body-parser](https://github.com/expressjs/body-parser).
Note: Formidable requires [gently](http://github.com/felixge/node-gently) to run the unit tests, but you won't need it for just using the library.
## Example
Parse an incoming file upload.
```javascript
var formidable = require('formidable'),
http = require('http'),
util = require('util');
http.createServer(function(req, res) {
if (req.url == '/upload' && req.method.toLowerCase() == 'post') {
// parse a file upload
var form = new formidable.IncomingForm();
form.parse(req, function(err, fields, files) {
res.writeHead(200, {'content-type': 'text/plain'});
res.write('received upload:\n\n');
res.end(util.inspect({fields: fields, files: files}));
});
return;
}
// show a file upload form
res.writeHead(200, {'content-type': 'text/html'});
res.end(
''
);
}).listen(8080);
```
## API
### Formidable.IncomingForm
```javascript
var form = new formidable.IncomingForm()
```
Creates a new incoming form.
```javascript
form.encoding = 'utf-8';
```
Sets encoding for incoming form fields.
```javascript
form.uploadDir = "/my/dir";
```
Sets the directory for placing file uploads in. You can move them later on using
`fs.rename()`. The default is `os.tmpdir()`.
```javascript
form.keepExtensions = false;
```
If you want the files written to `form.uploadDir` to include the extensions of the original files, set this property to `true`.
```javascript
form.type
```
Either 'multipart' or 'urlencoded' depending on the incoming request.
```javascript
form.maxFieldsSize = 20 * 1024 * 1024;
```
Limits the amount of memory all fields together (except files) can allocate in bytes.
If this value is exceeded, an `'error'` event is emitted. The default
size is 20MB.
```javascript
form.maxFileSize = 200 * 1024 * 1024;
```
Limits the size of uploaded file.
If this value is exceeded, an `'error'` event is emitted. The default
size is 200MB.
```javascript
form.maxFields = 1000;
```
Limits the number of fields that the querystring parser will decode. Defaults
to 1000 (0 for unlimited).
```javascript
form.hash = false;
```
If you want checksums calculated for incoming files, set this to either `'sha1'` or `'md5'`.
```javascript
form.multiples = false;
```
If this option is enabled, when you call `form.parse`, the `files` argument will contain arrays of files for inputs which submit multiple files using the HTML5 `multiple` attribute.
```javascript
form.bytesReceived
```
The amount of bytes received for this form so far.
```javascript
form.bytesExpected
```
The expected number of bytes in this form.
```javascript
form.parse(request, [cb]);
```
Parses an incoming node.js `request` containing form data. If `cb` is provided, all fields and files are collected and passed to the callback:
```javascript
form.parse(req, function(err, fields, files) {
// ...
});
form.onPart(part);
```
You may overwrite this method if you are interested in directly accessing the multipart stream. Doing so will disable any `'field'` / `'file'` events processing which would occur otherwise, making you fully responsible for handling the processing.
```javascript
form.onPart = function(part) {
part.addListener('data', function() {
// ...
});
}
```
If you want to use formidable to only handle certain parts for you, you can do so:
```javascript
form.onPart = function(part) {
if (!part.filename) {
// let formidable handle all non-file parts
form.handlePart(part);
}
}
```
Check the code in this method for further inspiration.
### Formidable.File
```javascript
file.size = 0
```
The size of the uploaded file in bytes. If the file is still being uploaded (see `'fileBegin'` event), this property says how many bytes of the file have been written to disk yet.
```javascript
file.path = null
```
The path this file is being written to. You can modify this in the `'fileBegin'` event in
case you are unhappy with the way formidable generates a temporary path for your files.
```javascript
file.name = null
```
The name this file had according to the uploading client.
```javascript
file.type = null
```
The mime type of this file, according to the uploading client.
```javascript
file.lastModifiedDate = null
```
A date object (or `null`) containing the time this file was last written to. Mostly
here for compatibility with the [W3C File API Draft](http://dev.w3.org/2006/webapi/FileAPI/).
```javascript
file.hash = null
```
If hash calculation was set, you can read the hex digest out of this var.
#### Formidable.File#toJSON()
This method returns a JSON-representation of the file, allowing you to
`JSON.stringify()` the file which is useful for logging and responding
to requests.
### Events
#### 'progress'
Emitted after each incoming chunk of data that has been parsed. Can be used to roll your own progress bar.
```javascript
form.on('progress', function(bytesReceived, bytesExpected) {
});
```
#### 'field'
Emitted whenever a field / value pair has been received.
```javascript
form.on('field', function(name, value) {
});
```
#### 'fileBegin'
Emitted whenever a new file is detected in the upload stream. Use this event if
you want to stream the file to somewhere else while buffering the upload on
the file system.
```javascript
form.on('fileBegin', function(name, file) {
});
```
#### 'file'
Emitted whenever a field / file pair has been received. `file` is an instance of `File`.
```javascript
form.on('file', function(name, file) {
});
```
#### 'error'
Emitted when there is an error processing the incoming form. A request that experiences an error is automatically paused, you will have to manually call `request.resume()` if you want the request to continue firing `'data'` events.
```javascript
form.on('error', function(err) {
});
```
#### 'aborted'
Emitted when the request was aborted by the user. Right now this can be due to a 'timeout' or 'close' event on the socket. After this event is emitted, an `error` event will follow. In the future there will be a separate 'timeout' event (needs a change in the node core).
```javascript
form.on('aborted', function() {
});
```
##### 'end'
```javascript
form.on('end', function() {
});
```
Emitted when the entire request has been received, and all contained files have finished flushing to disk. This is a great place for you to send your response.
## Changelog
[./CHANGELOG.md](./CHANGELOG.md)
## Credits
- [multipart-parser](http://github.com/FooBarWidget/multipart-parser): a C++
parser based on formidable
- [Ryan Dahl](http://twitter.com/ryah) for his work on
[http-parser](http://github.com/ry/http-parser) which heavily inspired the
initial `multipart_parser.js`.
From [Felix blog post](https://felixge.de/2013/03/11/the-pull-request-hack/):
- [Sven Lito](https://github.com/svnlto) for fixing bugs and merging patches
- [egirshov](https://github.com/egirshov) for contributing many improvements to the node-formidable multipart parser
- [Andrew Kelley](https://github.com/superjoe30) for also helping with fixing bugs and making improvements
- [Mike Frey](https://github.com/mikefrey) for contributing JSON support
## Contributing
If the documentation is unclear or has a typo, please click on the page's `Edit`
button (pencil icon) and suggest a correction. If you would like to help us fix
a bug or add a new feature, please check our [Contributing
Guide][contributing-url]. Pull requests are welcome!
## License
Formidable is licensed under the [MIT License][license-url].
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