Active Storage 附加模型

提供類別等級的 DSL 用於宣告 Active Record 模型的附件。

方法

#

*_attachment,
*_attachments,
*_blob,
*_blobs

H

has_many_attached,
has_one_attached

W

with_attached_*

實例公開方法

*_attachment 連結

傳回針對 has_one_attached 的附件。

User.last.avatar_attachment

來源： on GitHub

# File activestorage/lib/active_storage/attached/model.rb, line 13

*_attachments 連結

傳回針對 has_many_attached 的附件。

Gallery.last.photos_attachments

來源： on GitHub

# File activestorage/lib/active_storage/attached/model.rb, line 20

*_blob 連結

傳回針對 has_one_attached 附件的二進位大物件。

User.last.avatar_blob

來源： on GitHub

# File activestorage/lib/active_storage/attached/model.rb, line 27

*_blobs 連結

傳回針對 has_many_attached 附件的二進位大物件。

Gallery.last.photos_blobs

來源： on GitHub

# File activestorage/lib/active_storage/attached/model.rb, line 34

has_many_attached(name, dependent: :purge_later, service: nil, strict_loading: false) 連結

指定多個附件和模型之間的關聯。

class Gallery < ApplicationRecord
  has_many_attached :photos
end

在模型端沒有定義欄位，Active Storage 會處理記錄和附件之間的對應。

基本上，這個關聯以 has_many 關聯實作到 ActiveStorage::Attachment 記錄，並以 has_many-through 關聯實作到 ActiveStorage::Blob 記錄。這些關聯可做為 photos_attachments 和 photos_blobs 取得。但多數情況下您不必直接使用這些關聯。

反之，has_many_attached 會產生一個 ActiveStorage::Attached::Many 代理物件，提供存取關聯和工廠方法，例如 attach。

user.photos.attach(uploaded_file)

:dependent 選項預設為 :purge_later。這表示每當記錄被刪除時，附件會在背景中被清除（也就是說，刪除）。如果應用程式中沒有設定 ActiveJob::Backend 佇列轉接器，則應將其改設為 purge。

如果您需要附件使用與全域設定不同的服務，請傳遞 :service 選項。例如

class Gallery < ActiveRecord::Base
  has_many_attached :photos, service: :s3
end

:service 也可用來指定一個處理程序，它會呼叫模型實例

class Gallery < ActiveRecord::Base
  has_many_attached :photos, service: ->(gallery) { gallery.personal? ? :personal_s3 : :s3 }
end

為了避免 N+1 查詢，您可以將已附加的二進位大物件納入您的查詢，如下所示

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

如果您需要啟用 strict_loading 以避免延遲載入附件，請傳遞 :strict_loading 選項。您可以執行

class Gallery < ApplicationRecord
  has_many_attached :photos, strict_loading: true
end

注意：Active Storage 依賴多型關聯，這在資料庫中會儲存類別名稱。當變更使用 has_many 的類別名稱時，請確定也要更新對應列的 active_storage_attachments.record_type 多型類型欄位中的類別名稱。

資料來源：顯示 | 於 GitHub 上

# File activestorage/lib/active_storage/attached/model.rb, line 210
      def has_many_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
        ActiveStorage::Blob.validate_service_configuration(service, self, name) unless service.is_a?(Proc)

        generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
          # frozen_string_literal: true
          def #{name}
            @active_storage_attached ||= {}
            @active_storage_attached[:#{name}] ||= ActiveStorage::Attached::Many.new("#{name}", self)
          end

          def #{name}=(attachables)
            attachables = Array(attachables).compact_blank
            pending_uploads = attachment_changes["#{name}"].try(:pending_uploads)

            attachment_changes["#{name}"] = if attachables.none?
              ActiveStorage::Attached::Changes::DeleteMany.new("#{name}", self)
            else
              ActiveStorage::Attached::Changes::CreateMany.new("#{name}", self, attachables, pending_uploads: pending_uploads)
            end
          end
        CODE

        has_many :"#{name}_attachments", -> { where(name: name) }, as: :record, class_name: "ActiveStorage::Attachment", inverse_of: :record, dependent: :destroy, strict_loading: strict_loading
        has_many :"#{name}_blobs", through: :"#{name}_attachments", class_name: "ActiveStorage::Blob", source: :blob, strict_loading: strict_loading

        scope :"with_attached_#{name}", -> {
          if ActiveStorage.track_variants
            includes("#{name}_attachments": { blob: {
              variant_records: { image_attachment: :blob },
              preview_image_attachment: { blob: { variant_records: { image_attachment: :blob } } }
            } })
          else
            includes("#{name}_attachments": :blob)
          end
        }

        after_save { attachment_changes[name.to_s]&.save }

        after_commit(on: %i[ create update ]) { attachment_changes.delete(name.to_s).try(:upload) }

        reflection = ActiveRecord::Reflection.create(
          :has_many_attached,
          name,
          nil,
          { dependent: dependent, service_name: service },
          self
        )
        yield reflection if block_given?
        ActiveRecord::Reflection.add_attachment_reflection(self, name, reflection)
      end

has_one_attached(名稱、相依性：：後續清除、服務：nil、嚴格載入：false) 連結

指定單一附件與模型之間的關係。

class User < ApplicationRecord
  has_one_attached :avatar
end

模型側沒有定義任何欄位，模型與附件之間的對應由 Active Storage 處理。

在此基礎架構下，這個關聯是以 has_one 關聯實作的，會對應到 ActiveStorage::Attachment 記錄，同時也有個 has_one-through 關聯，會對應到 ActiveStorage::Blob 記錄。這些關聯可供使用，分別是 avatar_attachment 和 avatar_blob。但大多數情況下，您不需要直接使用這些關聯。

相反地，has_one_attached 會產生一個 ActiveStorage::Attached::One 代理，以提供存取關聯與工廠方法的方式，例如 attach

user.avatar.attach(uploaded_file)

:dependent 選項的預設值為 :purge_later。這表示每當要刪除某個記錄時，系統會在背景中清除 (亦即刪除) 該附件。如果應用程式中沒有設定 ActiveJob::Backend 佇列配接器，則改將其設定為 purge。

如果您需要附件使用與全域設定不同的服務，請傳遞 :service 選項。例如

class User < ActiveRecord::Base
  has_one_attached :avatar, service: :s3
end

:service 也可用來指定一個處理程序，它會呼叫模型實例

class User < ActiveRecord::Base
  has_one_attached :avatar, service: ->(user) { user.in_europe_region? ? :s3_europe : :s3_usa }
end

為了避免 N+1 查詢，您可以將已附加的二進位大物件納入您的查詢，如下所示

User.with_attached_avatar

如果您需要啟用 strict_loading 來防止附件延遲載入，請傳遞 :strict_loading 選項。您可以執行下列動作

class User < ApplicationRecord
  has_one_attached :avatar, strict_loading: true
end

注意：Active Storage 倚賴多型關聯，而多型關聯又會將類別名稱儲存在資料庫中。當變更使用 has_one_attached 的類別名稱時，請務必也要更新相應列的 active_storage_attachments.record_type 多型類型欄位中的類別名稱。

資料來源：顯示 | 於 GitHub 上

# File activestorage/lib/active_storage/attached/model.rb, line 108
      def has_one_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
        ActiveStorage::Blob.validate_service_configuration(service, self, name) unless service.is_a?(Proc)

        generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
          # frozen_string_literal: true
          def #{name}
            @active_storage_attached ||= {}
            @active_storage_attached[:#{name}] ||= ActiveStorage::Attached::One.new("#{name}", self)
          end

          def #{name}=(attachable)
            attachment_changes["#{name}"] =
              if attachable.nil? || attachable == ""
                ActiveStorage::Attached::Changes::DeleteOne.new("#{name}", self)
              else
                ActiveStorage::Attached::Changes::CreateOne.new("#{name}", self, attachable)
              end
          end
        CODE

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

        scope :"with_attached_#{name}", -> {
          if ActiveStorage.track_variants
            includes("#{name}_attachment": { blob: {
              variant_records: { image_attachment: :blob },
              preview_image_attachment: { blob: { variant_records: { image_attachment: :blob } } }
            } })
          else
            includes("#{name}_attachment": :blob)
          end
        }

        after_save { attachment_changes[name.to_s]&.save }

        after_commit(on: %i[ create update ]) { attachment_changes.delete(name.to_s).try(:upload) }

        reflection = ActiveRecord::Reflection.create(
          :has_one_attached,
          name,
          nil,
          { dependent: dependent, service_name: service },
          self
        )
        yield reflection if block_given?
        ActiveRecord::Reflection.add_attachment_reflection(self, name, reflection)
      end

with_attached_* 連結

在您的查詢中包含已附加的二進位大型物件，以避免 N+1 次查詢。

如果已啟用 ActiveStorage.track_variants，則也會包含變體記錄及其已附加的二進位大型物件。

User.with_attached_avatar

將 has_many_attached 的複數形式用於 with_attached_*

Gallery.with_attached_photos

資料來源：顯示 | 於 GitHub 上

# File activestorage/lib/active_storage/attached/model.rb, line 54
    class_methods do
      # Specifies the relation between a single attachment and the model.
      #
      #   class User < ApplicationRecord
      #     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.
      #
      # 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.
      #
      # Instead, +has_one_attached+ generates an ActiveStorage::Attached::One proxy to
      # provide access to the associations and factory methods, like +attach+:
      #
      #   user.avatar.attach(uploaded_file)
      #
      # The +:dependent+ option defaults to +:purge_later+. This means the attachment will be
      # purged (i.e. destroyed) in the background whenever the record is destroyed.
      # If an ActiveJob::Backend queue adapter is not set in the application set it to
      # +purge+ instead.
      #
      # If you need the attachment to use a service which differs from the globally configured one,
      # pass the +:service+ option. For example:
      #
      #   class User < ActiveRecord::Base
      #     has_one_attached :avatar, service: :s3
      #   end
      #
      # +:service+ can also be specified as a proc, and it will be called with the model instance:
      #
      #   class User < ActiveRecord::Base
      #     has_one_attached :avatar, service: ->(user) { user.in_europe_region? ? :s3_europe : :s3_usa }
      #   end
      #
      # To avoid N+1 queries, you can include the attached blobs in your query like so:
      #
      #   User.with_attached_avatar
      #
      # If you need to enable +strict_loading+ to prevent lazy loading of attachment,
      # pass the +:strict_loading+ option. You can do:
      #
      #   class User < ApplicationRecord
      #     has_one_attached :avatar, strict_loading: true
      #   end
      #
      # Note: Active Storage relies on polymorphic associations, which in turn store class names in the database.
      # When renaming classes that use <tt>has_one_attached</tt>, make sure to also update the class names in the
      # <tt>active_storage_attachments.record_type</tt> polymorphic type column of
      # the corresponding rows.
      def has_one_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
        ActiveStorage::Blob.validate_service_configuration(service, self, name) unless service.is_a?(Proc)

        generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
          # frozen_string_literal: true
          def #{name}
            @active_storage_attached ||= {}
            @active_storage_attached[:#{name}] ||= ActiveStorage::Attached::One.new("#{name}", self)
          end

          def #{name}=(attachable)
            attachment_changes["#{name}"] =
              if attachable.nil? || attachable == ""
                ActiveStorage::Attached::Changes::DeleteOne.new("#{name}", self)
              else
                ActiveStorage::Attached::Changes::CreateOne.new("#{name}", self, attachable)
              end
          end
        CODE

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

        scope :"with_attached_#{name}", -> {
          if ActiveStorage.track_variants
            includes("#{name}_attachment": { blob: {
              variant_records: { image_attachment: :blob },
              preview_image_attachment: { blob: { variant_records: { image_attachment: :blob } } }
            } })
          else
            includes("#{name}_attachment": :blob)
          end
        }

        after_save { attachment_changes[name.to_s]&.save }

        after_commit(on: %i[ create update ]) { attachment_changes.delete(name.to_s).try(:upload) }

        reflection = ActiveRecord::Reflection.create(
          :has_one_attached,
          name,
          nil,
          { dependent: dependent, service_name: service },
          self
        )
        yield reflection if block_given?
        ActiveRecord::Reflection.add_attachment_reflection(self, name, reflection)
      end

      # Specifies the relation between multiple attachments and the model.
      #
      #   class Gallery < ApplicationRecord
      #     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.
      #
      # 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.
      #
      # Instead, +has_many_attached+ generates an ActiveStorage::Attached::Many proxy to
      # provide access to the associations and factory methods, like +attach+:
      #
      #   user.photos.attach(uploaded_file)
      #
      # The +:dependent+ option defaults to +:purge_later+. This means the attachments will be
      # purged (i.e. destroyed) in the background whenever the record is destroyed.
      # If an ActiveJob::Backend queue adapter is not set in the application set it to
      # +purge+ instead.
      #
      # If you need the attachment to use a service which differs from the globally configured one,
      # pass the +:service+ option. For example:
      #
      #   class Gallery < ActiveRecord::Base
      #     has_many_attached :photos, service: :s3
      #   end
      #
      # +:service+ can also be specified as a proc, and it will be called with the model instance:
      #
      #   class Gallery < ActiveRecord::Base
      #     has_many_attached :photos, service: ->(gallery) { gallery.personal? ? :personal_s3 : :s3 }
      #   end
      #
      # To avoid N+1 queries, you can include the attached blobs in your query like so:
      #
      #   Gallery.where(user: Current.user).with_attached_photos
      #
      # If you need to enable +strict_loading+ to prevent lazy loading of attachments,
      # pass the +:strict_loading+ option. You can do:
      #
      #   class Gallery < ApplicationRecord
      #     has_many_attached :photos, strict_loading: true
      #   end
      #
      # Note: Active Storage relies on polymorphic associations, which in turn store class names in the database.
      # When renaming classes that use <tt>has_many</tt>, make sure to also update the class names in the
      # <tt>active_storage_attachments.record_type</tt> polymorphic type column of
      # the corresponding rows.
      def has_many_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
        ActiveStorage::Blob.validate_service_configuration(service, self, name) unless service.is_a?(Proc)

        generated_association_methods.class_eval <<-CODE, __FILE__, __LINE__ + 1
          # frozen_string_literal: true
          def #{name}
            @active_storage_attached ||= {}
            @active_storage_attached[:#{name}] ||= ActiveStorage::Attached::Many.new("#{name}", self)
          end

          def #{name}=(attachables)
            attachables = Array(attachables).compact_blank
            pending_uploads = attachment_changes["#{name}"].try(:pending_uploads)

            attachment_changes["#{name}"] = if attachables.none?
              ActiveStorage::Attached::Changes::DeleteMany.new("#{name}", self)
            else
              ActiveStorage::Attached::Changes::CreateMany.new("#{name}", self, attachables, pending_uploads: pending_uploads)
            end
          end
        CODE

        has_many :"#{name}_attachments", -> { where(name: name) }, as: :record, class_name: "ActiveStorage::Attachment", inverse_of: :record, dependent: :destroy, strict_loading: strict_loading
        has_many :"#{name}_blobs", through: :"#{name}_attachments", class_name: "ActiveStorage::Blob", source: :blob, strict_loading: strict_loading

        scope :"with_attached_#{name}", -> {
          if ActiveStorage.track_variants
            includes("#{name}_attachments": { blob: {
              variant_records: { image_attachment: :blob },
              preview_image_attachment: { blob: { variant_records: { image_attachment: :blob } } }
            } })
          else
            includes("#{name}_attachments": :blob)
          end
        }

        after_save { attachment_changes[name.to_s]&.save }

        after_commit(on: %i[ create update ]) { attachment_changes.delete(name.to_s).try(:upload) }

        reflection = ActiveRecord::Reflection.create(
          :has_many_attached,
          name,
          nil,
          { dependent: dependent, service_name: service },
          self
        )
        yield reflection if block_given?
        ActiveRecord::Reflection.add_attachment_reflection(self, name, reflection)
      end
    end

模組 ActiveStorage::Attached::Model

Active Storage 附加模型

實例公開方法

*_attachment 連結

*_attachments 連結

*_blob 連結

*_blobs 連結

has_many_attached(name, dependent: :purge_later, service: nil, strict_loading: false) 連結

has_one_attached(名稱、相依性：：後續清除、服務：nil、嚴格載入：false) 連結

with_attached_* 連結