Active Storage Attachment
Attachments associate records with blobs. Usually that’s a one record-many blobs relationship, but it is possible to associate many different records with the same blob. A foreign-key constraint on the attachments table prevents blobs from being purged if they’re still attached to any records.
Attachments also have access to all methods from ActiveStorage::Blob
.
If you wish to preload attachments or blobs, you can use these scopes:
# preloads attachments, their corresponding blobs, and variant records (if using `ActiveStorage.track_variants`)
User.all.with_attached_avatars
# preloads blobs and variant records (if using `ActiveStorage.track_variants`)
User.first.avatars.with_all_variant_records
Methods
Class Public methods
with_all_variant_records
Eager load all variant records on an attachment at once.
User.first.avatars.with_all_variant_records
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 45
scope :with_all_variant_records, -> { includes(blob: {
variant_records: { image_attachment: :blob },
preview_image_attachment: { blob: { variant_records: { image_attachment: :blob } } }
🔎 See on GitHub
Instance Public methods
blob
Returns the associated ActiveStorage::Blob
.
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 31
belongs_to :blob, class_name: "ActiveStorage::Blob", autosave: true, inverse_of: :attachments
🔎 See on GitHub
preview(transformations)
Returns an ActiveStorage::Preview
instance for the attachment with the set of transformations
provided. Example:
video.preview(resize_to_limit: [100, 100]).processed.url
or if you are using pre-defined variants:
video.preview(:thumb).processed.url
See ActiveStorage::Blob::Representable#preview
for more information.
Raises an ArgumentError
if transformations
is a Symbol
which is an unknown pre-defined variant of the attachment.
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 101
def preview(transformations)
transformations = transformations_by_name(transformations)
blob.preview(transformations)
end
🔎 See on GitHub
purge()
Synchronously deletes the attachment and purges the blob.
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 51
def purge
transaction do
delete
record.touch if record&.persisted?
end
blob&.purge
end
🔎 See on GitHub
purge_later()
Deletes the attachment and enqueues a background job to purge the blob.
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 60
def purge_later
transaction do
delete
record.touch if record&.persisted?
end
blob&.purge_later
end
🔎 See on GitHub
record
Returns the associated record.
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 25
belongs_to :record, polymorphic: true, touch: ActiveStorage.touch_attachment_records
🔎 See on GitHub
representation(transformations)
Returns an ActiveStorage::Preview
or an ActiveStorage::Variant
for the attachment with set of transformations
provided. Example:
avatar.representation(resize_to_limit: [100, 100]).processed.url
or if you are using pre-defined variants:
avatar.representation(:thumb).processed.url
See ActiveStorage::Blob::Representable#representation
for more information.
Raises an ArgumentError
if transformations
is a Symbol
which is an unknown pre-defined variant of the attachment.
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 120
def representation(transformations)
transformations = transformations_by_name(transformations)
blob.representation(transformations)
end
🔎 See on GitHub
variant(transformations)
Returns an ActiveStorage::Variant
or ActiveStorage::VariantWithRecord
instance for the attachment with the set of transformations
provided. Example:
avatar.variant(resize_to_limit: [100, 100]).processed.url
or if you are using pre-defined variants:
avatar.variant(:thumb).processed.url
See ActiveStorage::Blob::Representable#variant
for more information.
Raises an ArgumentError
if transformations
is a Symbol
which is an unknown pre-defined variant of the attachment.
📝 Source code
# File activestorage/app/models/active_storage/attachment.rb, line 82
def variant(transformations)
transformations = transformations_by_name(transformations)
blob.variant(transformations)
end
🔎 See on GitHub