Module: ActiveStorage::Attached::Macros

Defined in:
lib/active_storage/attached/macros.rb

Overview

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

Instance Method Summary collapse

Instance Method Details

#has_many_attached(name, dependent: :purge_later) ⇒ Object

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.



66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
 
# File 'lib/active_storage/attached/macros.rb', line 66

def has_many_attached(name, dependent: :purge_later)
  define_method(name) do
    instance_variable_get("@active_storage_attached_#{name}") ||
      instance_variable_set("@active_storage_attached_#{name}", ActiveStorage::Attached::Many.new(name, self))
  end

  if Rails.version < '4.0'
    has_many :"#{name}_attachments", conditions: proc { "name = '#{name}'" }, as: :record, class_name: "ActiveStorage::Attachment"
  else
    has_many :"#{name}_attachments", -> { where(name: name) }, as: :record, class_name: "ActiveStorage::Attachment"
  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
    before_destroy { public_send(name).purge_later }
  end
end

#has_one_attached(name, dependent: :purge_later) ⇒ Object

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.

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.



23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
 
# File 'lib/active_storage/attached/macros.rb', line 23

def has_one_attached(name, dependent: :purge_later)
  define_method(name) do
    instance_variable_get("@active_storage_attached_#{name}") ||
      instance_variable_set("@active_storage_attached_#{name}", ActiveStorage::Attached::One.new(name, self))
  end

  if Rails.version < '4.0'
    has_one :"#{name}_attachment", conditions: proc { "name = '#{name}'" }, class_name: "ActiveStorage::Attachment", as: :record
  else
    has_one :"#{name}_attachment", -> { where(name: name) }, class_name: "ActiveStorage::Attachment", as: :record
  end

  has_one :"#{name}_blob", through: :"#{name}_attachment", class_name: "ActiveStorage::Blob", source: :blob

  if dependent == :purge_later
    before_destroy { public_send(name).purge_later }
  end
end