< Back

April 24th

Covering:

• File Attachment Gems
• Shrine
• Adding Likes and Dislikes
• References

---

File Attachment Gems

• Shrine
• CarrierWave
• Paperclip

---

• Amazon S3 (Simple Storage Service)
• Heroku is designed to run apps, not to act as a storage solution
• Using Shrine to connect with S3 allows you to run apps on Heroku and deal with storage through S3
• Long story short just use Shrine, don’t bother with CarrierWave or Paperclip

---

Shrine

• rails new instashrine
• add devise, rspec-rails, shrine, pundit, dotenv-rails to gemfile
• bundle
• rails g rspec:install
• rails g devise:install
• rails g pundit:install
• rails g devise User
• rails g scaffold Photo image_data:text user:references description:text
• Create file named shrine.rb in initializers and add: ```ruby require “shrine” require “shrine/storage/file_system”

Shrine.storages = { cache: Shrine::Storage::FileSystem.new(“public”, prefix: “uploads/cache”), # temporary store: Shrine::Storage::FileSystem.new(“public”, prefix: “uploads/store”), # permanent }

Shrine.plugin :activerecord Shrine.plugin :cached_attachment_data # for forms

- Create `uploaders` folder in `app` with `image_uploader.rb` file inside:
```ruby 
class ImageUploader < Shrine
    # plugins and uploading logic
  end

• In photo.rb model add include ImageUploader::Attachment.new(:image) # adds an "image" virtual attribute
• Add @photo.user = current_user inside the create method in photo_controller.rb
• Add before_action :authenticate_user!, except: [:index, :show] at top of photo controller
• Add has_many :photos in user model
• Remove user_id from form partial and from pages_controller.rb
• Add the below inside the form: ```ruby

<%= form.label :image %> <%= form.hidden_field :image, value: @photo.cached_image_data %> <%= form.file_field :image, id: :photo_image_data %>

- Migrate database
- `rails g controller Pages index`
```ruby
def photo_params
      params.require(:photo).permit(:image, :description)
    end

• brew install imagemagick in terminal
• Add gem "image_processing", "~> 1.0" in Gemfile
• Copy to image_uploader.rb ```ruby require “image_processing/mini_magick”

class ImageUploader < Shrine plugin :processing plugin :versions # enable Shrine to handle a hash of files plugin :delete_raw # delete processed files after uploading

process(:store) do |io, context| original = io.download pipeline = ImageProcessing::MiniMagick.source(original)

size_80 = pipeline.resize_to_limit!(80, 80)
size_500 = pipeline.resize_to_limit!(500, 500)

original.close! #gets rid of image in memory

{ original: original, thumb: size_80, medium: size_300 }   end end ``` --- ## Adding Likes and Dislikes

• rails g migration CreateJoinTableLikes user photo
• Add to migration file:

  class CreateJoinTableLikes < ActiveRecord::Migration[5.1]
  def change
    create_join_table :users, :photos, table_name: :likes do |t|
      # t.index [:user_id, :photo_id]
      t.index [:photo_id, :user_id]
    end
  end
  end
  

• Migrate database
• Put in photo.rb model: ```ruby has_many_and_belongs_to_many :likers, class_name: “User”, join_table :likes

def liked_by?(user) likers.exists?(user.id) end

def toggle_liked_by(user) if liked_by?(user) likers.destroy(user) else likers « user end

- Add to routes:
```ruby
resources :photos do
    member do
      get 'likes'
    end
  end

• In photos_controller.rb: ```ruby before_action :set_photo, only: [:show, :edit, :update, :destroy, :like]

  at top

GET photos/1/like

def like @photo.toggle_liked_by(current_user) end

```

---

References

• Shrine Docs on Github
• Shrine Website