Provides the class-level DSL for declaring that an Active Record model has attached blobs.

Methods

Instance Public methods

has_many_attached(name, dependent: :purge_later)

Specifies the relation between multiple attachments and the model.

class Gallery < ActiveRecord::Base
  has_many_attached :photos
end

There are no columns defined on the model side, Active Storage takes care of the mapping between your records and the attachments.

To avoid N+1 queries, you can include the attached blobs in your query like so:

Gallery.where(user: Current.user).with_attached_photos

Under the covers, this relationship is implemented as a has_many association to a ActiveStorage::Attachment record and a has_many-through association to a ActiveStorage::Blob record. These associations are available as photos_attachments and photos_blobs. But you shouldn't need to work with these associations directly in most circumstances.

The system has been designed to having you go through the ActiveStorage::Attached::Many proxy that provides the dynamic proxy to the associations and factory methods, like #attach.

If the :dependent option isn't set, all the attachments will be purged (i.e. destroyed) whenever the record is destroyed.

📝 Source code 
# File activestorage/lib/active_storage/attached/macros.rb, line 77
    def has_many_attached(name, dependent: :purge_later)
      class_eval <<-CODE, __FILE__, __LINE__ + 1
        def #{name}
          @active_storage_attached_#{name} ||= ActiveStorage::Attached::Many.new("#{name}", self, dependent: #{dependent == :purge_later ? ":purge_later" : "false"})
        end

        def #{name}=(attachables)
          #{name}.attach(attachables)
        end
      CODE

      has_many :"#{name}_attachments", -> { where(name: name) }, as: :record, class_name: "ActiveStorage::Attachment", inverse_of: :record, dependent: false do
        def purge
          each(&:purge)
          reset
        end

        def purge_later
          each(&:purge_later)
          reset
        end
      end
      has_many :"#{name}_blobs", through: :"#{name}_attachments", class_name: "ActiveStorage::Blob", source: :blob

      scope :"with_attached_#{name}", -> { includes("#{name}_attachments": :blob) }

      if dependent == :purge_later
        after_destroy_commit { public_send(name).purge_later }
      else
        before_destroy { public_send(name).detach }
      end
    end
🔎 See on GitHub

has_one_attached(name, dependent: :purge_later)

Specifies the relation between a single attachment and the model.

class User < ActiveRecord::Base
  has_one_attached :avatar
end

There is no column defined on the model side, Active Storage takes care of the mapping between your records and the attachment.

To avoid N+1 queries, you can include the attached blobs in your query like so:

User.with_attached_avatar

Under the covers, this relationship is implemented as a has_one association to a ActiveStorage::Attachment record and a has_one-through association to a ActiveStorage::Blob record. These associations are available as avatar_attachment and avatar_blob. But you shouldn't need to work with these associations directly in most circumstances.

The system has been designed to having you go through the ActiveStorage::Attached::One proxy that provides the dynamic proxy to the associations and factory methods, like attach.

If the :dependent option isn't set, the attachment will be purged (i.e. destroyed) whenever the record is destroyed.

📝 Source code 
# File activestorage/lib/active_storage/attached/macros.rb, line 30
    def has_one_attached(name, dependent: :purge_later)
      class_eval <<-CODE, __FILE__, __LINE__ + 1
        def #{name}
          @active_storage_attached_#{name} ||= ActiveStorage::Attached::One.new("#{name}", self, dependent: #{dependent == :purge_later ? ":purge_later" : "false"})
        end

        def #{name}=(attachable)
          #{name}.attach(attachable)
        end
      CODE

      has_one :"#{name}_attachment", -> { where(name: name) }, class_name: "ActiveStorage::Attachment", as: :record, inverse_of: :record, dependent: false
      has_one :"#{name}_blob", through: :"#{name}_attachment", class_name: "ActiveStorage::Blob", source: :blob

      scope :"with_attached_#{name}", -> { includes("#{name}_attachment": :blob) }

      if dependent == :purge_later
        after_destroy_commit { public_send(name).purge_later }
      else
        before_destroy { public_send(name).detach }
      end
    end
🔎 See on GitHub

purge()

📝 Source code 
# File activestorage/lib/active_storage/attached/macros.rb, line 89
        def purge
          each(&:purge)
          reset
        end
🔎 See on GitHub

purge_later()

📝 Source code 
# File activestorage/lib/active_storage/attached/macros.rb, line 94
        def purge_later
          each(&:purge_later)
          reset
        end
🔎 See on GitHub