nodejs express and file uploading - file-io

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);

Answer 2

How about running this snippet from the example library?
https://github.com/visionmedia/express/blob/master/examples/multipart/app.js
/**
* Module dependencies.
*/
var express = require('express')
, form = require('connect-form');
var app = express.createServer(
// connect-form (http://github.com/visionmedia/connect-form)
// middleware uses the formidable middleware to parse urlencoded
// and multipart form data
form({ keepExtensions: true })
);
app.get('/', function(req, res){
res.send('<form method="post" enctype="multipart/form-data">'
+ '<p>Image: <input type="file" name="image" /></p>'
+ '<p><input type="submit" value="Upload" /></p>'
+ '</form>');
});
app.post('/', function(req, res, next){
// connect-form adds the req.form object
// we can (optionally) define onComplete, passing
// the exception (if any) fields parsed, and files parsed
req.form.complete(function(err, fields, files){
if (err) {
next(err);
} else {
console.log('\nuploaded %s to %s'
, files.image.filename
, files.image.path);
res.redirect('back');
}
});
// We can add listeners for several form
// events such as "progress"
req.form.on('progress', function(bytesReceived, bytesExpected){
var percent = (bytesReceived / bytesExpected * 100) | 0;
process.stdout.write('Uploading: %' + percent + '\r');
});
});
app.listen(3000);
console.log('Express app started on port 3000');
npm install express
npm install connect-form
node app.js
works fine for me...

Answer 3

I was able to get the connect-form package working finally, rookie mistake but, if you are using express make sure you tell the app to use the form module within your config function app.configure(function(){
app.use(form({ keepExtensions: true }));
(the in the post it will be in the files.yourfileuploadfieldname.filename variable)
-- with that said Im still interested to know how to do it from scratch, without connect-form, if its not incredibly difficult to explain.