Class: ActiveStorage::Analyzer

Relationships & Source Files
Namespace Children
Classes: `ImageAnalyzer`, `VideoAnalyzer`
Extension / Inclusion / Inheritance Descendants
Subclasses: ImageAnalyzer, ActiveStorage::Analyzer::NullAnalyzer, VideoAnalyzer
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, `Downloading`
Inherits:	Object
Defined in:	activestorage/lib/active_storage/analyzer.rb

Overview

This is an abstract base class for analyzers, which extract metadata from blobs. See ImageAnalyzer for an example of a concrete subclass.

#download_blob_to	Efficiently downloads blob data into the given file.
#download_blob_to_tempfile	Opens a new tempfile in `#tempdir` and copies blob data into it.
#tempdir	Returns the directory in which tempfiles should be opened.

[ GitHub ]

# File 'activestorage/lib/active_storage/analyzer.rb', line 19


def initialize(blob)
  @blob = blob
end

Implement this method in a concrete subclass. Have it return true when given a blob from which the analyzer can extract metadata.

[ GitHub ]

# File 'activestorage/lib/active_storage/analyzer.rb', line 15


def self.accept?(blob)
  false
end

[ GitHub ]

# File 'activestorage/lib/active_storage/analyzer.rb', line 11


attr_reader :blob

[ GitHub ]

# File 'activestorage/lib/active_storage/analyzer.rb', line 29


def logger #:doc:
  ActiveStorage.logger
end

Override this method in a concrete subclass. Have it return a ::Hash of metadata.

Raises:

[ GitHub ]

# File 'activestorage/lib/active_storage/analyzer.rb', line 24


def metadata
  raise NotImplementedError
end