S3FF

Using s3_file_field with paperclip

Install

1. Add javascript

in your application.js

//= require s3ff

2. Change file_field input to use s3_file_field

= form_for :user do |f|
  = f.s3_file_field :avatar

or if you're using simple_form

= simple_form_for :user do |f|
  = f.input :avatar do
    = f.s3_file_field :avatar, :class => "form-control"

3. Add footer

= include_s3ff_templates

NOTE: Feel free to modify & render the templates manually, but keep the s3ff_ prefixed CSS classes for our javascript to work properly.

What will happen

To illustate, if you have a file field like this

<input type="file" name="user[avatar]">

When s3ff kicks in, it would upgrade the field to a s3_file_field. When your user chooses a file, it will be uploaded, with a progress indicator, directly into your S3 bucket (see s3_file_field gem for configuration). Your form will be disabled during the upload and re-enabled once upload completes. After this process, 4 new hidden form fields will be attached to your form:

<input type="file" name="user[avatar_direct_url]" value="https://....">
<input type="file" name="user[avatar_file_name]" value="face.png">
<input type="file" name="user[avatar_file_size]" value="162534">
<input type="file" name="user[avatar_content_type]" value="image/png">

Code changes to your app

s3ff designed to minimize moving parts and code changes to your Rails app - all it does is give you 4 form fields in return for every direct s3 file upload that happened in your user's browser.

How you deal with these form fields are entirely up to you. Here's a simple way:

1. Edit strong parameters

If your controller was specifying

params.require(:user).permit(:avatar)

It would need to be changed to accept the new form fields

params.require(:user).permit(:avatar,
  :avatar_direct_url,
  :avatar_file_name,
  :avatar_file_size,
  :avatar_content_type
)

2. Upgrade model to also accept direct url

If your model was originally

class User < ActiveRecord::Base
  has_attached_file :avatar
end

Download the file from S3 when given avatar_direct_url. This leave all your existing Paperclip code and logic unchanged.

class User < ActiveRecord::Base
  has_attached_file :avatar

  attr_accessor :avatar_direct_url
  def avatar_direct_url=(value)
    self.avatar = open(value) if value.present?
  end
end

License

This repository is MIT-licensed.