simple_form custom inputs to get image/link previews with file uploads.
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Latest commit 51b58d3 Jul 13, 2016 @andreapavoni andreapavoni Merge pull request #20 from dcarneiro/master
allow users to set the preview url
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simple_form_fancy_uploads.gemspec Make it work properly with simple_form ~> 3.1 Jan 11, 2015

SimpleForm fancy uploads

A set of simple_form (~> 3.1) custom inputs to get image previews or a link to uploaded file.

This gem uses the new simple_form 3.1 ability to write your own form tags (check the simple_form-bootstrap example). In 90% of cases, you need some kind of preview when it comes to uploaded files (avatar, images, docs, etc..), why should I write the same markup each time?

What you get

There're only two new file inputs:

  • ImagePreview: guess what? when you edit an entry that contains an uploaded image, it will be shown (how many times did you this in a CMS?)
  • AttachmentPreview: this is a generic upload field, it will show a direct link to the file, so you can check what was uploaded.

How it works


Simply add gem 'simple_form_fancy_uploads' to your Gemfile and run bundle install


Here's a basic example, as you can see, it's just a matter of specify the input as :image_preview or :attachment_preview. If using :image_preview, you can also specify a :preview_version => :some_version_name inside the :input_html Hash. This will let you to show a custom version generated with Carrierwave. Nice, isn't it?

If you need to fallback on Carrierwave's #default_url method to show a default image defined in your upload class, set :use_default_url => true in the options hash.

<%= simple_form_for @some_model do |f| %>
  <!-- we specify that this is an image form upload input, and we want to show the 'thumb' version
  of the carrierwave upload to not break our layout with a non-resized image -->
  <%= f.input :some_image_field, as: :image_preview, input_html: {preview_version: :thumb} %>

  <!-- here's a *normal* attachment. with this input, a link to the filename will be shown
  if there's an uploaded file -->
  <%= f.input :some_attachment_field, as: :attachment_preview %>
<% end %>

If you want, you can pass the preview_url to the image on the input_html options. This might be useful when you don't have a model binded to the form.

<%= simple_form_for :user do |f| %>
  <%= f.input :image, as: :image_preview, input_html: { preview_url: image_url } %>
<% end %>


To get it work, you need:

  • simple_form ~> 3.1 (repetita iuvant)
  • carrierwave actually it's the most opinionated gem for uploads (thank you paperclip for the good times, but you know... life goes on)
  • ruby 1.9+ (it uses some 1.9's syntax)


  • clone this repo
  • run bundle install
  • run rspec spec

Contributions & Bugs

  • the easy way: go to issues page and blame me.
  • the hard way: repeat the above points, then show your power and send a pull request.


Copyright (c) 2014 Andrea Pavoni