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rails / 6.1 / activestorage / analyzer.html

class ActiveStorage::Analyzer

Parent:
Object

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

Attributes

blob[R]

Public Class Methods

accept?(blob) Show source 
# File activestorage/lib/active_storage/analyzer.rb, line 11
def self.accept?(blob)
  false
end

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

analyze_later?() Show source 
# File activestorage/lib/active_storage/analyzer.rb, line 17
def self.analyze_later?
  true
end

Implement this method in concrete subclasses. It will determine if blob analysis should be done in a job or performed inline. By default, analysis is enqueued in a job.

new(blob) Show source 
# File activestorage/lib/active_storage/analyzer.rb, line 21
def initialize(blob)
  @blob = blob
end

Public Instance Methods

metadata() Show source 
# File activestorage/lib/active_storage/analyzer.rb, line 26
def metadata
  raise NotImplementedError
end

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

Private Instance Methods

download_blob_to_tempfile(&block) Show source 
# File activestorage/lib/active_storage/analyzer.rb, line 32
def download_blob_to_tempfile(&block) #:doc:
  blob.open tmpdir: tmpdir, &block
end

Downloads the blob to a tempfile on disk. Yields the tempfile.

logger() Show source 
# File activestorage/lib/active_storage/analyzer.rb, line 36
def logger #:doc:
  ActiveStorage.logger
end
tmpdir() Show source 
# File activestorage/lib/active_storage/analyzer.rb, line 40
def tmpdir #:doc:
  Dir.tmpdir
end

© 2004–2020 David Heinemeier Hansson
Licensed under the MIT License.