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-rw-r--r--activestorage/lib/active_storage/analyzer/image_analyzer.rb36
1 files changed, 36 insertions, 0 deletions
diff --git a/activestorage/lib/active_storage/analyzer/image_analyzer.rb b/activestorage/lib/active_storage/analyzer/image_analyzer.rb
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+++ b/activestorage/lib/active_storage/analyzer/image_analyzer.rb
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+# frozen_string_literal: true
+
+module ActiveStorage
+ # Extracts width and height in pixels from an image blob.
+ #
+ # Example:
+ #
+ # ActiveStorage::Analyzer::ImageAnalyzer.new(blob).metadata
+ # # => { width: 4104, height: 2736 }
+ #
+ # This analyzer relies on the third-party [MiniMagick]{https://github.com/minimagick/minimagick} gem. MiniMagick requires
+ # the [ImageMagick]{http://www.imagemagick.org} system library. These libraries are not provided by Rails; you must
+ # install them yourself to use this analyzer.
+ class Analyzer::ImageAnalyzer < Analyzer
+ def self.accept?(blob)
+ blob.image?
+ end
+
+ def metadata
+ read_image do |image|
+ { width: image.width, height: image.height }
+ end
+ rescue LoadError
+ logger.info "Skipping image analysis because the mini_magick gem isn't installed"
+ {}
+ end
+
+ private
+ def read_image
+ download_blob_to_tempfile do |file|
+ require "mini_magick"
+ yield MiniMagick::Image.new(file.path)
+ end
+ end
+ end
+end