Extracts and stores metadata from the file associated with this blob using a relevant analyzer. Active Storage comes with built-in analyzers for images and videos. See ActiveStorage::Analyzer::ImageAnalyzer and ActiveStorage::Analyzer::VideoAnalyzer for information about the specific attributes they extract and the third-party libraries they require.

To choose the analyzer for a blob, Active Storage calls accept? on each registered analyzer in order. It uses the first analyzer for which accept? returns true when given the blob. If no registered analyzer accepts the blob, no metadata is extracted from it.

In a Rails application, add or remove analyzers by manipulating Rails.application.config.active_storage.analyzers in an initializer:

# Add a custom analyzer for Microsoft Office documents:
Rails.application.config.active_storage.analyzers.append DOCXAnalyzer

# Remove the built-in video analyzer:
Rails.application.config.active_storage.analyzers.delete ActiveStorage::Analyzer::VideoAnalyzer

Outside of a Rails application, manipulate ActiveStorage.analyzers instead.

You won’t ordinarily need to call this method from a Rails application. New blobs are automatically and asynchronously analyzed via analyze_later when they’re attached for the first time.

# File activestorage/app/models/active_storage/blob/analyzable.rb, line 29
def analyze
  update! metadata: metadata.merge(extract_metadata_via_analyzer)
end

Enqueues an ActiveStorage::AnalyzeJob which calls analyze, or calls analyze inline based on analyzer class configuration.

This method is automatically called for a blob when it’s attached for the first time. You can call it to analyze a blob again (e.g. if you add a new analyzer or modify an existing one).

# File activestorage/app/models/active_storage/blob/analyzable.rb, line 37
def analyze_later
  if analyzer_class.analyze_later?
    ActiveStorage::AnalyzeJob.perform_later(self)
  else
    analyze
  end
end

Returns true if the blob has been analyzed.

# File activestorage/app/models/active_storage/blob/analyzable.rb, line 46
def analyzed?
  analyzed
end