Question

Ok so ive already tried using connect-form and I couldnt get it working for some reason, but I figure I should understand how this works semi from scratch regardless.

I dont understand where the multipart/formdata file which I am uploaded is going, or how I can access it in my app when its posted to the url. — Id like to access the file data directy, and write the file output using the node fs module. — For instance:

    app.post('/testy', function(req, res){
       console.log(req.body);
       console.log(req.headers);
       res.redirect('back');

    });  

    app.get('/testy', function(req, res){
      res.send('<form method="post" action="/testy" enctype="multipart/form-data">'
        + '<p>Image: <input type="file" name="test" /></p>'
        + '<p><input type="submit" value="Upload" /></p>'
        + '</form>');
    });

So the only req var that is actually being logged there is the req headers, body is empty. (probably supposed to be I understand that). But what I dont get is where is the file data? Looking for the php equiv of the $_FILES array I supposed. — Here is my headers logged.

'accept: 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
'accept-language': 'en-us,en;q=0.5',
'accept-encoding': 'gzip,deflate',
'accept-charset': 'ISO-8859-1,utf-8;q=0.7,*;q=0.7',
'keep-alive': '115',
connection: 'keep-alive',
referer: 'http://127.0.0.1:3000/testy',
cookie: 'connect.sid=lDRpluTxjUJeuTmkXlybrYeZ.JYTB155s2DGce2dsyfv1Op5ISCY8uqyqJZK8NjlZ5jM; socketio=flashsocket',
'x-insight': 'activate',
'content-type': 'multipart/form-data; boundary=---------------------------5856401949371863571646035001',
'content-length': '30128' }

Any light shed upon what Im missing as always much appreciated!

Answer 1

Here is very verbose version without connect-form. As you can see, this is not efficient but trying to be instructive about how it works.

var express = require('express'),
    fs = require('fs');
    app = express.createServer();

app.post('/testy', function(req, res){
  var body = '';
  var header = '';
  var content_type = req.headers['content-type'];
  var boundary = content_type.split('; ')[1].split('=')[1];
  var content_length = parseInt(req.headers['content-length']);
  var headerFlag = true;
  var filename = 'dummy.bin';
  var filenameRegexp = /filename="(.*)"/m;
  console.log('content-type: ' + content_type);
  console.log('boundary: ' + boundary);
  console.log('content-length: ' + content_length);

  req.on('data', function(raw) {
    console.log('received data length: ' + raw.length);
    var i = 0;
    while (i < raw.length)
      if (headerFlag) {
        var chars = raw.slice(i, i+4).toString();
        if (chars === '\r\n\r\n') {
          headerFlag = false;
          header = raw.slice(0, i+4).toString();
          console.log('header length: ' + header.length);
          console.log('header: ');
          console.log(header);
          i = i + 4;
          // get the filename
          var result = filenameRegexp.exec(header);
          if (result[1]) {
            filename = result[1];
          }
          console.log('filename: ' + filename);
          console.log('header done');
        }
        else {
          i += 1;
        }
      }
      else { 
        // parsing body including footer
        body += raw.toString('binary', i, raw.length);
        i = raw.length;
        console.log('actual file size: ' + body.length);
      }
  });

  req.on('end', function() {
    // removing footer '\r\n'--boundary--\r\n' = (boundary.length + 8)
    body = body.slice(0, body.length - (boundary.length + 8))
    console.log('final file size: ' + body.length);
    fs.writeFileSync('files/' + filename, body, 'binary');
    console.log('done');
    res.redirect('back');
  })
});  

app.get('/testy', function(req, res){
  res.send('<form method="post" action="/testy" enctype="multipart/form-data">'
           + '<p>Image: <input type="file" name="test" /></p>'
           + '<p><input type="submit" value="Upload" /></p>'
           + '</form>');
});

app.listen(4000);