Upload a file to server using NodeJS and Swagger

I want to upload a file to a server using Swagger. I have created the YAML to upload file as follows:

 

    

/Upload:
post:
  summary: Uploads a file.
  operationId: bulkUpload
  consumes:
    - multipart/form-data
  parameters:
    - in: formData
      name: upfile
      type: file
      description: The file to upload.   
  responses:
    200:
      description: "File Uploaded"
  x-swagger-router-controller: "Default"

My DefaultService.js file contaians the function:

 

var fs = require('fs');

exports.bulkUpload = function(args, res, next)
{
  var stream = fs.createWriteStream("UploadedFile.txt");
  stream.once('open', function ()
  {
    stream.write('blah blah');                      //works - writes 'blah blah' to file
    stream.write(JSON.stringify(args.upfile.value));//bombs out after a while    
    stream.write(args.upfile);                      //does not work
    stream.write(args.upfile.value);                //does not work
    stream.end();
  });

  res.setHeader('Content-Type', 'application/json');
  res.statusCode = 200;
  res.end(JSON.stringify('File Uploaded'));
}

I want to upload the original file without having to create my own test file. How can I do this?

 

You will see that I am trying to write the uploaded file to a test file "UploadedFile.txt". It is currently failing as you can see from my attempts.