Adding Bootstrap Progress Bars for Refile

07 Apr 2015


The Refile gem is an awesome new file upload gem brought to us by jnicklas and the people over at Elabs. Depending on the situation and use case this can be an awesome replacement for Carrierwave. It offers a lot of really cool features like:

  • out of the box on the fly file manipulation
  • direct uploads
  • a javascript library to hook into events for the file

This will be a quick tutorial covering the integration of the Refile gems Javascript API hooks with Bootstrap 3’s progress bars in a Rails application. This will allow us to make some nice looking upload pages that provide great feedback to users, especially for large file. This will work with any ruby application (not just rails) as long as Bootstrap and Refile are supported.

Gems used:

Adding the Bootstrap Progress Bar

After adding Refile and Bootstrap to your Rails project you are ready to start adding your progress bars. Within your form that you have an attachment_field that you would like to track progress add a progress bar like so:

<div class="progress">
  <div class="progress-bar" role="progressbar" aria-valuenow="0" aria-valuemin="0" aria-valuemax="100" style="width: 0%;">
    <span class="sr-only">0% Complete</span>

Adding the Refile JS library

Now you just need to add the Refile JS library to the project. You will want to include this after jquery and turbolinks

# app/assets/javascripts/application.js
//= require jquery
//= require jquery_ujs
//= require turbolinks
//= require refile

Attaching hooks to make the progress bar work

Now that we have the Refile JS library in place we just need to hook it up to our progress bar and start letting the user know what is going on. The Refile JS exposes a lot of information when an requests takes place. Most notably for our uses are the uploaded and total attributes from the originalEvent that is returned. These will allow us to calculate the current progress percentage really easly so we can communicate it to the end-user.

$(document).on("upload:start", "form", function(e) {
  $(this).find("input[type=submit]").attr("disabled", true);

  progressBar = $("#" + $("progressbar")).parent();

$(document).on("upload:progress", "form", function(e) {
  // Get the progress bar to modify
  progressBar = $("#" + $("progressbar"));

  // Process upload details to get the percentage complete
  uploadDetail = e.originalEvent.detail;
  percentLoaded = uploadDetail.loaded;
  totalSize =;
  percentageComplete = Math.round((percentLoaded / totalSize) * 100);

  // Reflect the percentage on the progress bar
  progressBar.css("width", percentageComplete + "%");
  progressBar.text(percentageComplete + "%");

$(document).on("upload:success", "form", function(e) {
  progressBar = $("#" + $("progressbar"));

$(document).on("upload:failure", "form", function(e) {
  progressBar = $("#" + $("progressbar"));

$(document).on("upload:complete", "form", function(e) {
  if(!$(this).find("input.uploading").length) {

So lets break these down a bit and get into what we are doing on each event that is delegated.


This attaches to the start event for the current upload. Here is where we would want to make the progress bar visible since we had it hidden until the user uploads something. Also, we are disabling the submit button of the form so that a user can not accidentally submit the form while the file is still in the process of uploading.


This is the main event that we want to hook into for our progress bars. Here we will grab the progress bar that we want to update. Then we will get the information from the event that is returned to calculate the total percentage, the loaded and total attributes. Then we do a simple calculation of dividing the loaded by the total and multiplying by 100 to get the value as a percentage. The last thing that we will have to do is communicate the change in percentage back to the end user on the progress bar itself. This is done by changing the width attribute via css and changing the text in the progress bar to reflect the current percentage.


This will be used to communicate a successful upload to the server. One thing you may want to do on this event is change the color of the progress bar as we are doing here to a color that indicates a successful upload.


This event is just like upload:success but is instead, you guessed it, for failure.


This event is similar to the upload:complete and upload:success events but will actually fire before both of them and is only an indication of a completed XHR request. Because of this it is a good event to hook into for things like turning your submit button on. But be careful, this does not mean that your transaction completed successfully! You should use the upload:success event for that instead.

Wrap up

Now that we have the HTML and Javascript all setup you are ready to go. When you navigate to your file upload and select a file you should see your awesome progress bar showing the user their upload progress.

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