[Validator] Improve performance leveraging ActiveStorage::Blob#metada…

…ta metadata (#340)

README.md

@@ -598,6 +598,7 @@ Added features:
 - `dimension` validator now supports videos
 - `aspect_ratio` validator now supports videos
 - `processable_image` validator is now `processable_file` validator and supports image/video/audio
+- Major performance improvment have been added: we now only perform the expensive io analysis operation on the newly attached files. For previously attached files, we validate them using Rails `ActiveStorage::Blob#metadata` internal mecanism ([more here](https://github.com/rails/rails/blob/main/activestorage/app/models/active_storage/blob/analyzable.rb)).
 - All error messages have been given an upgrade and new variables that you can use
 
 But this major version bump also comes with some breaking changes. Below are the main breaking changes you need to be aware of:

lib/active_storage_validations.rb

@@ -11,6 +11,9 @@
 require 'active_storage_validations/analyzer/video_analyzer'
 require 'active_storage_validations/analyzer/audio_analyzer'
 
+require 'active_storage_validations/extensors/asv_blob_metadatable'
+require 'active_storage_validations/extensors/asv_marcelable'
+
 require 'active_storage_validations/railtie'
 require 'active_storage_validations/engine'
 require 'active_storage_validations/attached_validator'
@@ -23,8 +26,6 @@
 require 'active_storage_validations/size_validator'
 require 'active_storage_validations/total_size_validator'
 
-require 'active_storage_validations/marcel_extensor'
-
 ActiveSupport.on_load(:active_record) do
   send :include, ActiveStorageValidations
 end

lib/active_storage_validations/duration_validator.rb

@@ -21,7 +21,7 @@ def validate_each(record, attribute, _value)
       flat_options = set_flat_options(record)
 
       attachables_and_blobs(record, attribute).each do |attachable, blob|
-        duration = metadata_for(attachable)[:duration]
+        duration = metadata_for(blob, attachable)&.fetch(:duration, nil)
 
         if duration.to_i <= 0
           errors_options = initialize_error_options(options, attachable)

lib/active_storage_validations/extensors/asv_blob_metadatable.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module ActiveStorageValidations
+  module ASVBlobMetadatable
+    extend ActiveSupport::Concern
+
+    included do
+      def active_storage_validations_metadata
+        metadata.dig('custom', 'active_storage_validations')
+      end
+
+      def active_storage_validations_metadata=(value)
+        metadata['custom'] ||= {}
+        metadata['custom']['active_storage_validations'] = value
+      end
+    end
+  end
+end

lib/active_storage_validations/railtie.rb

@@ -2,5 +2,10 @@
 
 module ActiveStorageValidations
   class Railtie < ::Rails::Railtie
+    initializer 'active_storage_validations.extend_active_storage_blob' do
+      Rails.application.config.to_prepare do
+        ActiveStorage::Blob.include(ActiveStorageValidations::ASVBlobMetadatable)
+      end
+    end
   end
 end

lib/active_storage_validations/shared/asv_analyzable.rb

@@ -12,7 +12,17 @@ module ASVAnalyzable
 
     private
 
-    def metadata_for(attachable)
+    # Retrieve the ASV metadata from the blob.
+    # If the blob has not been analyzed by our gem yet, the gem will analyze the
+    # attachable with the corresponding analyzer and set the metadata in the
+    # blob.
+    def metadata_for(blob, attachable)
+      return blob.active_storage_validations_metadata if blob.active_storage_validations_metadata.present?
+
+      blob.active_storage_validations_metadata = generate_metadata_for(attachable)
+    end
+
+    def generate_metadata_for(attachable)
       analyzer_for(attachable).metadata
     end
 

lib/active_storage_validations/shared/asv_attachable.rb

@@ -18,7 +18,7 @@ module ASVAttachable
     # to perform file analyses.
     def validate_changed_files_from_metadata(record, attribute)
       attachables_and_blobs(record, attribute).each do |attachable, blob|
-        is_valid?(record, attribute, attachable, metadata_for(attachable))
+        is_valid?(record, attribute, attachable, metadata_for(blob, attachable))
       end
     end
 

test/dummy/app/models/aspect_ratio/validator/is_performance_optimized.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: aspect_ratio_validator_is_performance_optimizeds
+#
+#  id         :integer          not null, primary key
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class AspectRatio::Validator::IsPerformanceOptimized < ApplicationRecord
+  has_one_attached :is_performance_optimized
+  has_many_attached :is_performance_optimizeds
+  validates :is_performance_optimized, aspect_ratio: :square
+  validates :is_performance_optimizeds, aspect_ratio: :square
+end

test/dummy/app/models/dimension/validator/is_performance_optimized.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: dimension_validator_is_performance_optimizeds
+#
+#  id         :integer          not null, primary key
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class Dimension::Validator::IsPerformanceOptimized < ApplicationRecord
+  has_one_attached :is_performance_optimized
+  has_many_attached :is_performance_optimizeds
+  validates :is_performance_optimized, dimension: { width: 150, height: 150 }
+  validates :is_performance_optimizeds, dimension: { width: 150, height: 150 }
+end

test/dummy/app/models/duration/validator/is_performance_optimized.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: duration_validator_is_performance_optimizeds
+#
+#  id         :integer          not null, primary key
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class Duration::Validator::IsPerformanceOptimized < ApplicationRecord
+  has_one_attached :is_performance_optimized
+  has_many_attached :is_performance_optimizeds
+  validates :is_performance_optimized, duration: { less_than: 2.seconds }
+  validates :is_performance_optimizeds, duration: { less_than: 2.seconds }
+end

test/dummy/app/models/processable_file/validator/is_performance_optimized.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+# == Schema Information
+#
+# Table name: processable_file_validator_is_performance_optimizeds
+#
+#  id         :integer          not null, primary key
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#
+
+class ProcessableFile::Validator::IsPerformanceOptimized < ApplicationRecord
+  has_one_attached :is_performance_optimized
+  has_many_attached :is_performance_optimizeds
+  validates :is_performance_optimized, processable_file: true
+  validates :is_performance_optimizeds, processable_file: true
+end

test/dummy/db/schema.rb

@@ -95,6 +95,18 @@
     end
   end
 
+  %i(
+    aspect_ratio
+    dimension
+    duration
+    processable_file
+  ).each do |validator|
+    create_table :"#{validator}_validator_is_performance_optimizeds", force: :cascade do |t|
+      t.datetime :created_at, null: false
+      t.datetime :updated_at, null: false
+    end
+  end
+
   %w(proc_option invalid_named_argument invalid_is_xy_argument).each do |invalid_case|
     create_table :"aspect_ratio_validator_check_validity_#{invalid_case.pluralize}", force: :cascade do |t|
       t.datetime :created_at, null: false

test/extensors/asv_blob_metadatable_test.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+
+describe ActiveStorageValidations::ASVBlobMetadatable do
+  let(:blob) { ActiveStorage::Blob.new }
+
+  it "adds our gem's getter method to ActiveStorage::Blob custom metadata" do
+    assert blob.respond_to?(:active_storage_validations_metadata)
+  end
+
+  it "adds our gem's setter method to ActiveStorage::Blob custom metadata" do
+    blob.active_storage_validations_metadata = { 'duration' => '1.0' }
+    assert blob.active_storage_validations_metadata == { 'duration' => '1.0' }
+  end
+end

test/validators/aspect_ratio_validator_test.rb

@@ -2,6 +2,7 @@
 
 require 'test_helper'
 require 'validators/shared_examples/checks_validator_validity'
+require 'validators/shared_examples/is_performance_optimized'
 require 'validators/shared_examples/works_fine_with_attachables'
 require 'validators/shared_examples/works_with_all_rails_common_validation_options'
 
@@ -242,6 +243,18 @@
     end
   end
 
+  describe 'Blob Metadata' do
+    let(:attachable) do
+      {
+        io: File.open(Rails.root.join('public', 'image_150x150.png')),
+        filename: 'image_150x150.png',
+        content_type: 'image/png'
+      }
+    end
+
+    include IsPerformanceOptimized
+  end
+
   describe 'Rails options' do
     include WorksWithAllRailsCommonValidationOptions
   end

test/validators/duration_validator_test.rb

@@ -2,6 +2,7 @@
 
 require 'test_helper'
 require 'validators/shared_examples/checks_validator_validity'
+require 'validators/shared_examples/is_performance_optimized'
 require 'validators/shared_examples/works_with_all_rails_common_validation_options'
 
 describe ActiveStorageValidations::DurationValidator do
@@ -248,6 +249,18 @@
     end
   end
 
+  describe 'Blob Metadata' do
+    let(:attachable) do
+      {
+        io: File.open(Rails.root.join('public', 'audio.mp3')),
+        filename: 'audio.mp3',
+        content_type: 'audio/mp3'
+      }
+    end
+
+    include IsPerformanceOptimized
+  end
+
   describe 'Rails options' do
     include WorksWithAllRailsCommonValidationOptions
   end

test/validators/processable_file_validator_test.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'test_helper'
+require 'validators/shared_examples/is_performance_optimized'
 require 'validators/shared_examples/works_fine_with_attachables'
 require 'validators/shared_examples/works_with_all_rails_common_validation_options'
 
@@ -55,6 +56,18 @@
     end
   end
 
+  describe 'Blob Metadata' do
+    let(:attachable) do
+      {
+        io: File.open(Rails.root.join('public', 'audio.mp3')),
+        filename: 'audio.mp3',
+        content_type: 'audio/mp3'
+      }
+    end
+
+    include IsPerformanceOptimized
+  end
+
   describe 'Rails options' do
     include WorksWithAllRailsCommonValidationOptions
   end

test/validators/shared_examples/is_performance_optimized.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module IsPerformanceOptimized
+  extend ActiveSupport::Concern
+
+  included do
+    subject { validator_test_class::IsPerformanceOptimized.new(params) }
+
+    let(:validator_class) { "ActiveStorageValidations::#{validator_test_class.name.delete('::')}".constantize }
+
+    describe "when the attachable blob has not been analyzed by our gem yet" do
+      before { subject.is_performance_optimized.attach(attachable) }
+
+      it "calls the corresponding media analyzer (expensive operation) once" do
+        assert_called_on_instance_of(validator_class, :generate_metadata_for, times: 1, returns: {}) do
+          subject.valid?
+        end
+      end
+    end
+
+    describe "when an attachable blob has already been analyzed by our gem" do
+      before do
+        subject.is_performance_optimizeds.attach(attachable)
+        subject.save!
+      end
+
+      it "only calls the corresponding media analyzer (expensive operation) on the new attachable" do
+        assert_called_on_instance_of(validator_class, :generate_metadata_for, times: 1, returns: {}) do
+          subject.is_performance_optimizeds.attach(attachable)
+        end
+      end
+    end
+  end
+end