expressjs file upload, check whether there was indeed a file sent, specify max filesize & keep its name

Question

Working with expressjs for about a month by now I have stumbled across the problem of file uploads. Despite consulting Google & various blogs I have failed finding an answer to the following three questions:

What do I have to do / what settings for bodyParser do I have to choose in order to:

1. Make sure there was indeed a file uploaded (currently, when submitting the form without choosing a file an empty file gets created).

2. Where can I specify a value for the maxium size a file is allowed to have?

3. How can I omit the renaming of the file?

Currently I am including bodyParser in my express (v. 3.0.0) app with the following option:

{keepExtensions: true, uploadDir: __dirname + '/public/uploads'}

Answer 1

I recently ran into a similar problem. for Question #2, check http://www.senchalabs.org/connect/middleware-limit.html

app.use(express.limit('4M')); // in your app.configure()

app.post('/upload', function(req, res) {
    var fs = require('fs'),
        file = req.files.myfile; //your file field;


    if(file.size === 0) { // question #1
        fs.unlinkSync(file.path);
        res.redirect('/error?');
    } else { //question #3
        var fn = file.path.split('/');
        fs.rename(file.path, file.path.replace(fn[fn.length-1], file.name));
        res.redirect('/success?');
    }
});

Answer 2

About your concern

Make sure there was indeed a file uploaded (currently, when submitting the form without choosing a file an empty file gets created).

After long search I found a great solution

First you need to install node-formidable

Then after including the library, to check if file uploaded in the first place

var form = new formidable.IncomingForm();

form.parse(req, function(err, fields, files) {
  if (Object.keys(files).length !== 0) {
    console.log("File exists")
  } else {
    console.log("File does not exist")
  }
});

And about the size you can check this.

form.maxFieldsSize = 2 * 1024 * 1024;

Best regards.

Abdulaziz Noor