expiring_asset_links

CarrierWave FOG Expiring Asset Links

Handles storing and generating CarrierWave FOG expiring asset link stored in string and text attributes of ActiveRecord objects

This is helpful when using a WYSIWYG that inserts and previews assets directly from S3 using full S3 URLs. These URLs need to be updated each time the object is reloaded. When used in conjunction with CarrierWave and FOG gems, this gem will automatically update these links for you.

Dependencies

the following gems are required

gem 'rails', '>= 4.0.0'
gem 'carrierwave'
gem 'fog'

Installation

install manually

gem install expiring_asset_links

or add it to your Gemfile

gem 'carrierwave'

Usage

configure CarrierWave

your configuration must satisfy the following requirements:

• define storage :fog
• set Expires in s3_headers

class AssetUploader < CarrierWave::Uploader::Base
  storage :fog

  def s3_headers
    { "Expires" => 5.minutes.from_how.httpdate }
  end

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

end

add an initializer with your CarrierWave Uploader store_dir matching Regexp

if you wish to change the default store_dir in your CarrierWave Uploader you will need to create a Regexp that captures the object class name and id from the path

create an initializer, such as config/initializers/expiring_asset_links.rb and include your configuration with Regexp

ExpiringAssetLinks.configure do |conf|
  conf.fog_directory = /\/\S+\/(?<name>[a-z_]+)\/[a-z_]+\/(?<id>\d+)/
end

the path defined in CarrierWave Uploader store_dir, such as uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}, must match the Regexp in your configuration once generated by CarrierWave and must capture the class name as <name> and the object id as <id>

/\/\S+\/(?<name>[a-z_]+)\/[a-z_]+\/(?<id>\d+)/.match("uploads/class_name/uploader_name/100")
  #=> #<MatchData "uploads/class_name/uploader_name/100" name:"model_class_name" id:"100">

mount an uploader for any class containing an assets

you may use as many different classes as you would like, but each may only contain one mounted uploader

class Image
  mount_uploader :image, ImageUploader

end

class Attachment
  mount_uploader :file, FileUploader

end

specify the attributes that will contain asset links

the attributes specified should contain fully qualified asset URLs generated by CarrierWave with the Expires value specified when saved, these URLs will be automatically updated each time the attribute is accessed

class Document < ActiveRecord::Base
  attr_expiring_asset_links :body

end

class Article < ActiveRecord::Base
  attr_expiring_asset_links :summary, :body

end

Notes

the url that is generated by CarrierWave may not immediately follow a letter or underscore in the content of the attribute specified as attr_expiring_asset_links, this will prevent the gem from properly parsing the data

example of proper placement (the double quote character is no a letter or an underscore)

<h2>
  Section One
</h2>
<p>
  This is the first section in the body of the document.
  It includes an image.
</p>
<img src="https://test.s3-us-east-1.amazonaws.com/uploads/test/99/asset/file_attachment/sample.jpg">

example of improper placement (no space between 'at' and 'https')

<h2>
  Section One
</h2>
<p>
  This is the first section in the body of the document.
  It includes an image, you may view it athttps://test.s3-us-east-1.amazonaws.com/uploads/test/99/asset/file_attachment/sample.jpg
</p>