Parse http requests with content-type multipart/form-data
, also known as file uploads.
See also busboy - a faster alternative which may be worth looking into.
Content-Length
of each part.npm install multiparty
Parse an incoming multipart/form-data
request.
var multiparty = require('multiparty') , http = require('http') , util = require('util') http.createServer(function(req, res) { if (req.url === '/upload' && req.method === 'POST') { // parse a file upload var form = new multiparty.Form(); 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);
var form = new multiparty.Form(options)
Creates a new form. Options:
encoding
- sets encoding for the incoming form fields. Defaults to utf8
.maxFieldSize
- Limits the amount of memory a field (not a file) can allocate in bytes. If this value is exceeded, an error
event is emitted. The default size is 2MB.maxFields
- Limits the number of fields that will be parsed before emitting an error
event. A file counts as a field in this case. Defaults to 1000.autoFields
- Enables field
events. This is automatically set to true
if you add a field
listener.autoFiles
- Enables file
events. This is automatically set to true
if you add a file
listener.uploadDir
- Only relevant when autoFiles
is true
. The directory for placing file uploads in. You can move them later using fs.rename()
. Defaults to os.tmpDir()
.hash
- Only relevant when autoFiles
is true
. If you want checksums calculated for incoming files, set this to either sha1
or md5
. Defaults to off.Parses an incoming node.js request
containing form data. If cb
is provided, autoFields
and autoFiles
are set to true
and all fields and files are collected and passed to the callback:
form.parse(req, function(err, fieldsObject, filesObject, fieldsList, filesList) { // ... });
It is often convenient to access a field or file by name. In this situation, use fieldsObject
or filesObject
. However sometimes, as in the case of a <input type="file" multiple="multiple">
the multipart stream will contain multiple files of the same input name, and you are interested in all of them. In this case, use filesList
.
Another example is when you do not care what the field name of a file is; you are merely interested in a single upload. In this case, set maxFields
to 1 (assuming no other fields expected besides the file) and use filesList[0]
.
The amount of bytes received for this form so far.
The expected number of bytes in this form.
You definitely want to handle this event. If not your server will crash when users submit bogus multipart requests!
Emitted when a part is encountered in the request. part
is a ReadableStream
. It also has the following properties:
headers
- the headers for this part. For example, you may be interested in content-type
.name
- the field name for this partfilename
- only if the part is an incoming filebyteOffset
- the byte offset of this part in the request bodybyteCount
- assuming that this is the last part in the request, this is the size of this part in bytes. You could use this, for example, to set the Content-Length
header if uploading to S3. If the part had a Content-Length
header then that value is used here instead.Emitted when the request is aborted. This event will be followed shortly by an error
event. In practice you do not need to handle this event.
Emitted after all parts have been parsed and emitted. Not emitted if an error
event is emitted. This is typically when you would send your response.
By default multiparty will not touch your hard drive. But if you add this listener, multiparty automatically sets form.autoFiles
to true
and will stream uploads to disk for you.
name
- the field name for this filefile
- an object with these properties:fieldName
- same as name
- the field name for this fileoriginalFilename
- the filename that the user reports for the filepath
- the absolute path of the uploaded file on diskheaders
- the HTTP headers that were sent along with this filesize
- size of the file in bytesIf you set the form.hash
option, then file
will also contain a hash
property which is the checksum of the file.
name
- field namevalue
- string field value