multiparser

a streams2 compatible multipart-form parser

npm install multiparser
18 downloads in the last month
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A streams2 compatible multipart-form parser. Hacked from formidable.

Why

Formidable currently doesn't work with node >= 9.4. Also a good excuse to learn streams2.

How

The module exports a class Multiparser which inherits from Stream.Writable. Http request streams can be piped to instances which will emit 'part' events (essentially instances of Stream.PassThrough) that can then be piped around as needed (to file, s3, etc). Backpressure from parts' destinations are magically transmitted back to the Multiparser's source.

Install

npm install multiparser

Usage

The code below is pretty much straight from example/http.js

var fs = require('fs')
var Multiparser = require('multiparser')
var http = require("http")
var updir = '/tmp/'

http.createServer(function (req, res) {
  if (req.url === '/upload' && req.method === 'POST') {

    var error = null
    var progress = 0
    var parser = new Multiparser(req)

    parser.on('error', function (err) {
      error = err
    })

    parser.on('progress', function (parsed, total) {
      var currentProgress = ~~(parsed / total * 100)
      if (currentProgress != progress) {
        console.log('uploading...', currentProgress, req._readableState.length)
        progress = currentProgress
      }
    })

    parser.on('part', function (part) {
      part.on('end', function () {
        if (part.filename) {
          console.log('uploaded file "' + part.name + '" to ' + updir + part.filename)
        } else if (part.value) {
          console.log('parsed field "' + part.name + '" as "' + part.value + '"')
        }
      })

      if (part.filename) {
        var file = fs.createWriteStream(updir + part.filename)
        part.pipe(file)
      } else {
        part.value = ''
        part.on('readable', function () {
          part.value += part.read()
        })
        part.read(0)
      }
    })

    parser.on('end', function () {
      if (error) {
        res.writeHeaders(500)
        return res.end(err.message)
      } else {
        res.end('all parsed!')
      }
    })

  } else {

    res.end('<html>\
      <form enctype="multipart/form-data" method="POST" action="/upload">\
      <input name="fieldup" type="text" /><br>\
      <input name="fileup" type="file" multiple="true" /><br>\
      <input type="submit" value="upload" />\
      </form>\
      </html>')

  }
}).listen(8080)

License

MIT

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