README

Requirements

• ImageMagick
• Paperclip gem
• Rails 4.2 or higher
• Ruby 2.0 or higher

Steps

• Create a new Rails app
• Add nav bar to application.html.erb
• Add a Photos controller
• Set up the routes
• Add your model and migration
• migrate
• Integrate paperclip gem
• Bundle
• add attributes to photos table
  • rails generate paperclip photo image
• migrate
• add paperclip functionality to model
  • has_attached_file :image
• set up controller
  • just have to permit image
  • other fields are taken care of in paperclip
• create view for new action
  • use f.file_field :image
• extract errors to a partial in views/shared_errors.html.erb
• Paperclip requires content type validation

  validates_attachment :image,
                   content_type: { content_type: ["image/jpeg", "image/gif", "image/png"] }
  

• you are now ready to upload your first file
• create index view
  • iterate over @photos array
  • views/photos/_photo.html.erb partial will be used by default
• generate thumbnails with ImageMagick

Notes

• Download ImageMagick

  • I recommend downloading MacPorts first and then running sudo port install ImageMagick
  • Using Homebrew didn't update the necessary dependencies as easily and was a huge headache

• Paperclip cares about the security of your app like no one else does! Starting from version 4, it is required to have at least a content type validation in your model

  • But, what if we’re seasoned developers and can take care of ourselves? Can we tell Paperclip that our attachments should not be validated? But, of course:
  • do_not_validate_attachment_file_type :avatar

Resources

• SitePoint Paperclip tutorial
• RMagick Docs
• ImageMagick Download
• MacPorts Download
• Paperclip Docs