has_many_attached (name, dependent: :purge_later, service: nil, strict_loading: false)
public
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.
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.
If you need the attachment to use a service which differs from the globally
configured one, pass the :service option. For instance:
class Gallery < ActiveRecord :: Base
has_many_attached :photos , service : :s3
end
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 Show source # File activestorage/lib/active_storage/attached/model.rb, line 182
def has_many_attached(name, dependent: :purge_later, service: nil, strict_loading: false)
validate_service_configuration(name, service)
generated_association_methods.class_eval # 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, __FILE__, __LINE__ + 1
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: %[ 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