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# Formidable [](http://travis-ci.org/felixge/node-formidable) ## Purpose A node.js module for parsing form data, especially file uploads. ## Current status This module was developed for [Transloadit](http://transloadit.com/), a service focused on uploading and encoding images and videos. It has been battle-tested against hundreds of GB of file uploads from a large variety of clients and is considered production-ready. ## 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 This is a low level package, and if you're using a high level framework such as Express, chances are it's already included in it. You can [read this discussion](http://stackoverflow.com/questions/11295554/how-to-disable-express-bodyparser-for-file-uploads-node-js) about how Formidable is integrated with Express. Via [npm](http://github.com/isaacs/npm): ``` npm install formidable@latest ``` Manually: ``` git clone git://github.com/felixge/node-formidable.git formidable vim my.js # var formidable = require('./formidable'); ``` 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( '<form action="/upload" enctype="multipart/form-data" method="post">'+ '<input type="text" name="title"><br>'+ '<input type="file" name="upload" multiple="multiple"><br>'+ '<input type="submit" value="Upload">'+ '</form>' ); }).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 = 2 * 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 2MB. ```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' ```javascript form.on('progress', function(bytesReceived, bytesExpected) { }); ``` Emitted after each incoming chunk of data that has been parsed. Can be used to roll your own progress bar. #### 'field' ```javascript form.on('field', function(name, value) { }); ``` #### 'fileBegin' Emitted whenever a field / value pair has been received. ```javascript form.on('fileBegin', function(name, file) { }); ``` #### 'file' Emitted whenever a new file is detected in the upload stream. Use this even if you want to stream the file to somewhere else while buffering the upload on the file system. 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 ### v1.0.14 * Add failing hash tests. (Ben Trask) * Enable hash calculation again (Eugene Girshov) * Test for immediate data events (Tim Smart) * Re-arrange IncomingForm#parse (Tim Smart) ### v1.0.13 * Only update hash if update method exists (Sven Lito) * According to travis v0.10 needs to go quoted (Sven Lito) * Bumping build node versions