File Upload hangs with Multer in Krakenjs application

[Prabhash Rathore]

I am using multer (^0.1.6) in a Nodejs Kraken application to upload a file. I looked at the multer documentation on npm and it seemed it's pretty straightforward to use this module for file upload.

But I have been facing issues while uploading file on my local machine. Interestingly, I notice the file gets uploaded but my server hangs and the control never goes to the next middleware in the application which is responsible for rendering the next page.

I also noticed that when the server is hung, it tried to upload the file again and finally times out saying "No data received". As a result of multer's retry, I see two copies of same file uploaded.

Here is my kraken application code using multer module:

index.js (root leve index.js at same level as package.json)

-------------------------------------------------------------

    ...

    .....

    app = module.exports = express();

    app.use(kraken(options));

    app = module.exports = express();

    app.use(kraken(options));

    app.on('start', function () {

    console.log('Application ready to serve requests.');

    console.log('Environment: %s', app.kraken.get('env:env'));

    });

   app.use(multer({

    dest: '/Users/abc/temp/fileuploads',

    limits: {

        fieldNameSize: 500,

        files: 2,

        fields: 5

    },

    rename: function (fieldname, filename) {

        return fieldname + filename + Date.now();

    },

    onFileUploadStart: function (file) {

        console.log('Upload starting for filename: ' + file.originalname);

    },

    onFileUploadData: function (file, data) {

        console.log(data.length + ' of ' + file.fieldname + ' arrived')

    },

    onParseStart: function () {

        console.log('Form parsing started at: ', new Date())

    },

    onParseEnd: function (req, next) {

        console.log('Form parsing completed at: ', new Date());

        next();

    },

    onFileUploadComplete: function (file) {

        console.log(file.fieldname + ' uploaded to  ' + file.path);

    },

    onFileSizeLimit: function (file) {

        console.log('Failed: ', file.originalname)

        fs.unlink('./' + file.path) // delete the partially written file

    },

    onFilesLimit: function () {

        console.log('Crossed file limit!')

    },

    onFieldsLimit: function () {

        console.log('Crossed fields limit!')

    },

    onPartsLimit: function () {

        console.log('Crossed parts limit!')

    },

    onError: function(error, next) {

        console.log("Error occurred while uploading the file!!");

        next(error);

    }

    }));

index.js (under controllers directory of Kraken application)

-------------------------------------------------------------

    router.post('/upload', function (req, res) {

       console.log("File Uploaded");

       model.status = "File Uploaded!!";

       var body = req.body;

       console.log("File attributes: " + JSON.stringify(body));

       var files = req.files;

       console.log("Files: " + JSON.stringify(files));

       res.render('uploadfile/datauploadform', model);

   });

Here are the application logs after I start uploading the file (notice multer tried to upload same file twice before timing out):

Form parsing started at:  Sat Jan 10 2015 01:29:45 GMT-0800 (PST)

Upload starting for filename: HelloNashorn.js

35 of file arrived

file uploaded to  /Users/abc/temp/fileuploads/fileHelloNashorn1420882185450.js

Form parsing completed at:  Sat Jan 10 2015 01:29:45 GMT-0800 (PST)

Form parsing started at:  Sat Jan 10 2015 01:31:45 GMT-0800 (PST)

Upload starting for filename: HelloNashorn.js

35 of file arrived

file uploaded to  /Users/abc/temp/fileuploads/fileHelloNashorn1420882305450.js

Form parsing completed at:  Sat Jan 10 2015 01:31:45 GMT-0800 (PST)

Appreciate any help!