[English] HOW TO UPLOAD IMAGE TO S3 USING CARRIERWAVE ON RAILS

1. ADD GEM CARRIERWAVE

Carrierwave is gem provides a simple and extremly flexibale way to upload files from Ruby application.

gem 'carrierwave'

gem 'fog' # Support storing file in AWS

2. GENERATE AN UPLOADER

rails generate uploader CoverImage

this should give you a file in:

app/uploader/cover_image_uploader.rb

3. CONFIGURE IN UPLOADER

It should something like this:

class CoverImageUploader < CarrierWave::Uploader::Base

  storage :fog

  
  ...

  def store_dir
    "#{Rails.env}/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  def extension_white_list
    %w(jpg jpeg gif png)
  end

  ...
end

4. MOUNT THE UPLOADER IN MODEL (ACTIVERECORD)

class Post < ActiveRecord::Base
  mount_uploader :cover_image, CoverImageUploader

  ...
end

5. CONFIGURE TO UPLOAD FILE TO S3

We use the ‘fog‘ gem which supports storing file in AWS, Google, Local and Rackspace.

Create an initializer for this:

config/initializers/carrierwave.rb

You need to configure some options like this:

CarrierWave.configure do |config|
  config.fog_credentials = {
    provider: 'AWS',
    aws_access_key_id: ENV['AWS_KEY'],
    aws_secret_access_key: ENV['AWS_SECRET_KEY'],
    region: 'ap-southeast-1'
  }
  config.fog_directory = ENV['S3_BUCKET_NAME']
end

region : should be one of [ ‘eu-west-1’, ‘us-east-1’, ‘ap-southeast-1’, ‘us-west-1’, ‘ap-northeast-1’ ]

fog_directory : Bucket Name in S3