How to access file uploaded by $http and HTML5 FileReader

I am trying to upload an image inside an Angular app, the code looks like this:

      var f = document.getElementById('product-image').files[0],
        r = new FileReader();
      r.onloadend = function (e) {
          var data = e.target.result;
          $http({
              method: 'POST',
              data: data,
              url: host + '/uploadFile?' + $rootScope.user._id,
              headers: {
                  'Content-Type': 'multipart/form-data',
                  'X-File-Name': f.name,
                  'X-File-Size': f.size,
                  'X-File-Type': f.type

              }
          })
            .success(function (data, status, headers, config) {
                console.log(data)
            });

      }
      r.readAsArrayBuffer(f);

When I have a look at Chrome Header fields of the request, they all look good with values.

Now, how do I access and save that file from the backend endpoint in NodeJS and Express? Do I look inside req variable as usual? Where do I look for the file and its content and meta?