express-busboy.js

express-busboy.js

var BusBoy  = require('busboy'),
    fs      = require('fs'),
    path    = require('path');

var RE_MIME = /^(?:multipart\/.+)|(?:application\/x-www-form-urlencoded)$/i;

// options will have limit and uploadDir.
exports = module.exports = function(options){
    return function multipart(req, res, next) {
        
        if (req.method === 'GET'
            || req.method === 'HEAD'
            || !hasBody(req)
            || !RE_MIME.test(mime(req))) {
            return next();    
        }
        
        var busboy = new BusBoy({ 
            headers: req.headers, 
            limits: {
                fileSize: (options.limit || 1) * 1024 * 1024
            } 
        });
        
        req.files = req.files || {};
        req.body = req.body || {};

        busboy.on('file', function (fieldname, file, filename, encoding, mimetype) {
            var filePath = path.join(options.uploadDir, filename);

            file.on('limit', function() {
                var err = new Error('File size too large.');
                err.status = 413;
                next(err);
            });

            file.on('end', function () {
                req.files[fieldname] = {
                    type: mimetype,
                    encoding: encoding,
                    name: filename,
                    path: filePath
                };
            });

            file.pipe(fs.createWriteStream(filePath));
        });

        busboy.on('field', function (fieldname, val) {
            req.body[fieldname] = val;
        });

        busboy.on('end', function () {
            next();
        });

        req.pipe(busboy);
    }
};

function hasBody(req) {
    var encoding = 'transfer-encoding' in req.headers,
        length = 'content-length' in req.headers
            && req.headers['content-length'] !== '0';
    return encoding || length;
}

function mime(req) {
    var str = req.headers['content-type'] || '';
    return str.split(';')[0];
}