Representation of a single attachment to a model.

Methods

Instance Public methods

attach(attachable)

Associates a given attachment with the current record, saving it to the database.

person.avatar.attach(params[:avatar]) # ActionDispatch::Http::UploadedFile object
person.avatar.attach(params[:signed_blob_id]) # Signed reference to blob from direct upload
person.avatar.attach(io: File.open("/path/to/face.jpg"), filename: "face.jpg", content_type: "image/jpg")
person.avatar.attach(avatar_blob) # ActiveStorage::Blob object

Source: 

# File activestorage/lib/active_storage/attached/one.rb, line 22
def attach(attachable)
  blob_was = blob if attached?
  blob = create_blob_from(attachable)

  unless blob == blob_was
    transaction do
      detach
      write_attachment build_attachment(blob: blob)
    end

    blob_was.purge_later if blob_was && dependent == :purge_later
  end
end

attached?()

Returns true if an attachment has been made.

class User < ActiveRecord::Base
  has_one_attached :avatar
end

User.new.avatar.attached? # => false

Source: 

# File activestorage/lib/active_storage/attached/one.rb, line 43
def attached?
  attachment.present?
end

attachment()

Returns the associated attachment record.

You don't have to call this method to access the attachment's methods as they are all available at the model level.

Source: 

# File activestorage/lib/active_storage/attached/one.rb, line 12
def attachment
  record.public_send("#{name}_attachment")
end

detach()

Deletes the attachment without purging it, leaving its blob in place.

Source: 

# File activestorage/lib/active_storage/attached/one.rb, line 48
def detach
  if attached?
    attachment.destroy
    write_attachment nil
  end
end

purge()

Directly purges the attachment (i.e. destroys the blob and attachment and deletes the file on the service).

Source: 

# File activestorage/lib/active_storage/attached/one.rb, line 57
def purge
  if attached?
    attachment.purge
    write_attachment nil
  end
end

purge_later()

Purges the attachment through the queuing system.

Source: 

# File activestorage/lib/active_storage/attached/one.rb, line 65
def purge_later
  if attached?
    attachment.purge_later
  end
end