Module: Mongoid::Grid::ClassMethods

Defined in:
lib/mongoid/grid.rb

Instance Method Summary collapse

Instance Method Details

#attachment(name, prefix = 'grid') ⇒ Object

Declare an attachment for the object

eg: attachment :image



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# File 'lib/mongoid/grid.rb', line 21

def attachment(name,prefix='grid')
  ##
  # Callbacks to handle the attachment saving and deleting
  after_save     :create_attachments
  after_save     :delete_attachments
  after_destroy  :destroy_attachments

  ##
  # Fields for the attachment.
  #
  # Only the _id is really needed, the others are helpful cached
  # so you don't need to hit GridFS
  field "#{name}_id".to_sym,   :type => BSON::ObjectID
  field "#{name}_name".to_sym, :type => String
  field "#{name}_size".to_sym, :type => Integer
  field "#{name}_type".to_sym, :type => String

  ##
  # Add this name to the attachment_types
  attachment_types.push(name).uniq!

  ##
  # Return the GridFS object.
  # eg: image.filename, image.read
  define_method(name) do
    grid.get(attributes["#{name}_id"]) if attributes["#{name}_id"]
  end
  
  ##
  # Returns true if attachment exists.
  # eg: image?
  define_method("#{name}?") do
    !!attributes["#{name}_id"]
  end
  
  ##
  # Create a method to set the attachment
  # eg: object.image = File.open('/tmp/somefile.jpg')
  define_method("#{name}=") do |file|
    if file.respond_to?(:read)
      send(:create_attachment, name, file)
    else
      send(:delete_attachment, name, send("#{name}_id"))
    end
  end
  
  ##
  # Return the relative URL to the file for use with Rack::Grid
  # eg: /grid/4ba69fde8c8f369a6e000003/somefile.png
  define_method("#{name}_url") do
    _id   = send("#{name}_id")
    _name = send("#{name}_name")
    ["/#{prefix}", _id, _name].join('/') if _id && _name
  end

end

#grid ⇒ Object

Accessor to GridFS



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# File 'lib/mongoid/grid.rb', line 80

def grid
  @grid ||= Mongo::Grid.new(Mongoid.database)
end