Getting downloads to work between angularjs and express.js

I can get the raw data of the file that I am requesting, but I can't get the browser to serve the file to the user. Do I need to use iframes?

   //Client code
   download_file: function (path, callback) {
       $http.post('/download/client_file', {path:path}).
           success(function(data, status, headers, config) {
                console.log(data); //this contains the raw data of the res.download 
                                   //from the server.
           });
   }

   //server code
   res.download(file); // the path is proper

I used the code below in my services file for downloading items and it worked great. I got it from http://filamentgroup.com/lab/jquery_plugin_for_requesting_ajax_like_file_downloads/

$('<form action="'+ url +'" method="'+ ('post') +'">'+inputs+'</form>')
               .appendTo('body').submit().remove();

Depending on the file type, and how the headers are set on it, you may find it vastly easier to simply call location.href="uriString"; from your JS. File should download immediately, using the window you're already in. If it's JSON or text data, you may need to tweak the headers to make it download rather than rendering inline... ("content-disposition: attachment", perhaps...)