upload.js

import Ember from 'ember';
import XHR from 'ember-xhr';

/**
 * On the rails server, this creates an active record that stores the
 * filename and generates the pre-signed url, the return format is
 * something like:
 *
 *  {
 *    "upload": {
 *      "filename": "bob.tgz",
 *      "url": 'http://thepresigned-url'
 *    }
 *  }
 */

export default Ember.Route.extend({
  actions: {
    /**
     * `file` is a File object read from input.file
     * @param {File} file
     */
    performUpload(file) {
      $.post('/uploads', {
        filename: file.name
      }).then(Ember.run.bind(this,function(data) {
        var xhr = XHR.create();
        xhr.open(data.upload.url);
        xhr.send(file);
        this.set('controller.xhr', xhr);
      }));
    }
  }
});