Class: Para::Cloneable::AttachmentsCloner

Inherits:
Object
  • Object
show all
Defined in:
lib/para/cloneable/attachments_cloner.rb

Constant Summary collapse

ATTACHMENTS_RELATION_REGEX =

Handle both one and many attachment relations

/_attachments?\z/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(original, clone, dictionary) ⇒ AttachmentsCloner

Returns a new instance of AttachmentsCloner.



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# File 'lib/para/cloneable/attachments_cloner.rb', line 9

def initialize(original, clone, dictionary)
  @original = original
  @clone = clone
  @dictionary = dictionary
end

Instance Attribute Details

#clone ⇒ Object (readonly)

Returns the value of attribute clone.



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# File 'lib/para/cloneable/attachments_cloner.rb', line 4

def clone
  @clone
end

#dictionary ⇒ Object (readonly)

Returns the value of attribute dictionary.



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# File 'lib/para/cloneable/attachments_cloner.rb', line 4

def dictionary
  @dictionary
end

#original ⇒ Object (readonly)

Returns the value of attribute original.



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# File 'lib/para/cloneable/attachments_cloner.rb', line 4

def original
  @original
end

Instance Method Details

#clone! ⇒ Object 



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# File 'lib/para/cloneable/attachments_cloner.rb', line 15

def clone!
  return unless defined?(ActiveStorage)

  attachment_reflections = original.class.reflections.select do |name, reflection|
    name.to_s.match(ATTACHMENTS_RELATION_REGEX) &&
      reflection.options[:class_name] == 'ActiveStorage::Attachment'
  end

  attachment_reflections.each do |name, reflection|
    association_target = original.send(name)
    next unless association_target

    if reflection.collection?
      association_target.each do |attachment|
        clone_attachment_if_needed(name, attachment)
      end
    else
      clone_attachment_if_needed(name, association_target)
    end
  end
end

#clone_attachment(name, original_attachment) ⇒ Object 



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# File 'lib/para/cloneable/attachments_cloner.rb', line 48

def clone_attachment(name, original_attachment)
  association_name = name.gsub(ATTACHMENTS_RELATION_REGEX, '')
  original_blob = original_attachment.blob

  # Handle missing file in storage service by bypassing the attachment cloning
  return unless ActiveStorage::Blob.service.exist?(original_blob&.key)

  Para::ActiveStorageDownloader.new(original_attachment).download_blob_to_tempfile do |tempfile|
    attachment_target = clone.send(association_name)

    cloned_blob = ActiveStorage::Blob.create_and_upload!(
      io: tempfile,
      filename: original_blob.filename,
      content_type: original_blob.content_type
    )

    attachment_target.attach(cloned_blob)
    cloned_attachment = find_cloned_attachment(attachment_target, original_blob)

    # Store the cloned attachment and blob into the deep_cloneable dictionary used
    # by the `deep_clone` method to ensure that, if needed during the cloning
    # operation, they won't be cloned once more and are accessible for processing
    store_cloned(original_attachment, cloned_attachment)
    store_cloned(original_blob, cloned_blob)
  end
end

#clone_attachment_if_needed(name, attachment) ⇒ Object 



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# File 'lib/para/cloneable/attachments_cloner.rb', line 37

def clone_attachment_if_needed(name, attachment)
  return if attachment.nil?

  store_key = store_key_for(attachment)

  # If the attachment has already been cloned, we don't need to clone it again
  return if dictionary[store_key]&.key?(attachment)

  clone_attachment(name, attachment)
end

#find_cloned_attachment(attachment_target, original_blob) ⇒ Object

Seemlessly handle one and many attachment relations return values and fetch the attachment that we just cloned by comparing blobs checksum, as depending which ActiveStorage version we’re on (Rails 5.2 or 6), the ‘#attach` method doesn’t always return the same, so for now we still handle the Rails 5.2 case.



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# File 'lib/para/cloneable/attachments_cloner.rb', line 79

def find_cloned_attachment(attachment_target, original_blob)
  attachments = if attachment_target.attachments.any?
                  attachment_target.attachments
                else
                  [attachment_target.attachment]
                end

  attachment = attachments.find do |att|
    att.blob.checksum == original_blob.checksum
  end
end

#store_cloned(source, clone) ⇒ Object

This stores the source and clone resources into the deep_clone dictionary, which simulates what the deep_cloneable gem does when it clones a resource



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# File 'lib/para/cloneable/attachments_cloner.rb', line 94

def store_cloned(source, clone)
  store_key = store_key_for(source)

  dictionary[store_key] ||= {}
  dictionary[store_key][source] = clone
end

#store_key_for(attachment) ⇒ Object 



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# File 'lib/para/cloneable/attachments_cloner.rb', line 101

def store_key_for(attachment)
  attachment.class.name.tableize.to_sym
end