Tracking new attachment styles with a Rake task to refresh them

lib/paperclip.rb

@@ -39,6 +39,7 @@
 require 'paperclip/attachment'
 require 'paperclip/storage'
 require 'paperclip/callback_compatibility'
+require 'paperclip/missing_attachment_styles'
 require 'paperclip/railtie'
 require 'logger'
 require 'cocaine'
@@ -269,6 +270,7 @@ def has_attached_file name, options = {}
       end
 
       attachment_definitions[name] = {:validations => []}.merge(options)
+      Paperclip.classes_with_attachments << self
 
       after_save :save_attached_files
       before_destroy :destroy_attached_files

lib/paperclip/missing_attachment_styles.rb

@@ -0,0 +1,86 @@
+
+require 'set'
+module Paperclip
+
+  class << self
+    attr_accessor :classes_with_attachments
+    attr_writer :registered_attachments_styles_path
+    def registered_attachments_styles_path
+      @registered_attachments_styles_path ||= Rails.root.join('public/system/paperclip_attachments.yml').to_s
+    end
+  end
+
+  self.classes_with_attachments = Set.new
+
+
+  # Get list of styles saved on previous deploy (running rake paperclip:refresh:missing_styles)
+  def self.get_registered_attachments_styles
+    YAML.load_file(Paperclip.registered_attachments_styles_path)
+  rescue Errno::ENOENT
+    nil
+  end
+  private_class_method :get_registered_attachments_styles
+
+  def self.save_current_attachments_styles!
+    File.open(Paperclip.registered_attachments_styles_path, 'w') do |f|
+      YAML.dump(current_attachments_styles, f)
+    end
+  end
+
+  # Returns hash with styles for all classes using Paperclip.
+  # Unfortunately current version does not work with lambda styles:(
+  #   {
+  #     :User => {:avatar => [:small, :big]},
+  #     :Book => {
+  #       :cover => [:thumb, :croppable]},
+  #       :sample => [:thumb, :big]},
+  #     }
+  #   }
+  def self.current_attachments_styles
+    Hash.new.tap do |current_styles|
+      Paperclip.classes_with_attachments.each do |klass|
+        klass.attachment_definitions.each do |attachment_name, attachment_attributes|
+          # TODO: is it even possible to take into account Procs?
+          next if attachment_attributes[:styles].kind_of?(Proc)
+          attachment_attributes[:styles].try(:keys).try(:each) do |style_name|
+            klass_sym = klass.to_s.to_sym
+            current_styles[klass_sym] ||= Hash.new
+            current_styles[klass_sym][attachment_name.to_sym] ||= Array.new
+            current_styles[klass_sym][attachment_name.to_sym] << style_name.to_sym
+            current_styles[klass_sym][attachment_name.to_sym].map!(&:to_s).sort!.map!(&:to_sym).uniq!
+          end  
+        end  
+      end  
+    end
+  end
+  private_class_method :current_attachments_styles
+
+  # Returns hash with styles missing from recent run of rake paperclip:refresh:missing_styles
+  #   {
+  #     :User => {:avatar => [:big]},
+  #     :Book => {
+  #       :cover => [:croppable]},
+  #     }
+  #   }
+  def self.missing_attachments_styles
+    current_styles = current_attachments_styles
+    registered_styles = get_registered_attachments_styles
+
+    Hash.new.tap do |missing_styles|
+      current_styles.each do |klass, attachment_definitions|
+        attachment_definitions.each do |attachment_name, styles|
+          registered = registered_styles[klass][attachment_name] rescue []
+          missed = styles - registered 
+          if missed.present?
+            klass_sym = klass.to_s.to_sym
+            missing_styles[klass_sym] ||= Hash.new
+            missing_styles[klass_sym][attachment_name.to_sym] ||= Array.new
+            missing_styles[klass_sym][attachment_name.to_sym].concat(missed.to_a)
+            missing_styles[klass_sym][attachment_name.to_sym].map!(&:to_s).sort!.map!(&:to_sym).uniq!
+          end
+        end
+      end  
+    end
+  end
+
+end

lib/tasks/paperclip.rake

@@ -60,6 +60,22 @@ namespace :paperclip do
         end
       end
     end
+
+    desc "Regenerates missing thumbnail styles for all classes using Paperclip."
+    task :missing_styles => :environment do
+      # Force loading all model classes to never miss any has_attached_file declaration:
+      Dir[Rails.root + 'app/models/**/*.rb'].each { |path| load path }
+      Paperclip.missing_attachments_styles.each do |klass, attachment_definitions|
+        attachment_definitions.each do |attachment_name, missing_styles|
+          puts "Regenerating #{klass} -> #{attachment_name} -> #{missing_styles.inspect}"
+          ENV['CLASS'] = klass.to_s
+          ENV['ATTACHMENT'] = attachment_name.to_s
+          ENV['STYLES'] = missing_styles.join(',')
+          Rake::Task['paperclip:refresh:thumbnails'].execute
+        end
+      end  
+      Paperclip.save_current_attachments_styles!
+    end
   end
 
   desc "Cleans out invalid attachments. Useful after you've added new validations."

test/helper.rb

@@ -20,7 +20,7 @@
   puts "debugger disabled"
 end
 
-ROOT = File.expand_path(File.join(File.dirname(__FILE__), '..'))
+ROOT = Pathname(File.expand_path(File.join(File.dirname(__FILE__), '..')))
 
 def silence_warnings
   old_verbose, $VERBOSE = $VERBOSE, nil

test/paperclip_missing_attachment_styles_test.rb

@@ -0,0 +1,80 @@
+require './test/helper'
+
+class PaperclipMissingAttachmentStylesTest < Test::Unit::TestCase
+
+  context "Paperclip" do
+    setup do
+      Paperclip.classes_with_attachments = Set.new
+    end 
+
+    teardown do
+      File.unlink(Paperclip.registered_attachments_styles_path) rescue nil
+    end
+
+    should "be able to keep list of models using it" do
+      assert_kind_of Set, Paperclip.classes_with_attachments 
+      assert Paperclip.classes_with_attachments.empty?, 'list should be empty'
+      rebuild_model
+      assert_equal [Dummy].to_set, Paperclip.classes_with_attachments
+    end
+
+    should "enable to get and set path to registered styles file" do
+      assert_equal ROOT.join('public/system/paperclip_attachments.yml').to_s, Paperclip.registered_attachments_styles_path
+      Paperclip.registered_attachments_styles_path = '/tmp/config/paperclip_attachments.yml'
+      assert_equal '/tmp/config/paperclip_attachments.yml', Paperclip.registered_attachments_styles_path
+      Paperclip.registered_attachments_styles_path = nil
+      assert_equal ROOT.join('public/system/paperclip_attachments.yml').to_s, Paperclip.registered_attachments_styles_path
+    end
+
+    should "be able to get current attachment styles" do
+      assert_equal Hash.new, Paperclip.send(:current_attachments_styles)
+      rebuild_model :styles => {:croppable => '600x600>', :big => '1000x1000>'}
+      expected_hash = { :Dummy => {:avatar => [:big, :croppable]}}
+      assert_equal expected_hash, Paperclip.send(:current_attachments_styles)
+    end
+
+    should "be able to save current attachment styles for further comparison" do
+      rebuild_model :styles => {:croppable => '600x600>', :big => '1000x1000>'}
+      Paperclip.save_current_attachments_styles!
+      expected_hash = { :Dummy => {:avatar => [:big, :croppable]}}
+      assert_equal expected_hash, YAML.load_file(Paperclip.registered_attachments_styles_path)
+    end
+
+    should "be able to read registered attachment styles from file" do
+      rebuild_model :styles => {:croppable => '600x600>', :big => '1000x1000>'}
+      Paperclip.save_current_attachments_styles!
+      expected_hash = { :Dummy => {:avatar => [:big, :croppable]}}
+      assert_equal expected_hash, Paperclip.send(:get_registered_attachments_styles)
+    end
+
+    should "be able to calculate differences between registered styles and current styles" do
+      rebuild_model :styles => {:croppable => '600x600>', :big => '1000x1000>'}
+      Paperclip.save_current_attachments_styles!
+      rebuild_model :styles => {:thumb => 'x100', :export => 'x400>', :croppable => '600x600>', :big => '1000x1000>'}
+      expected_hash = { :Dummy => {:avatar => [:export, :thumb]} }
+      assert_equal expected_hash, Paperclip.missing_attachments_styles
+
+      ActiveRecord::Base.connection.create_table :books, :force => true
+      class ::Book < ActiveRecord::Base
+        has_attached_file :cover, :styles => {:small => 'x100', :large => '1000x1000>'}
+        has_attached_file :sample, :styles => {:thumb => 'x100'}
+      end
+
+      expected_hash = {
+        :Dummy => {:avatar => [:export, :thumb]},
+        :Book => {:sample => [:thumb], :cover => [:large, :small]}
+      }
+      assert_equal expected_hash, Paperclip.missing_attachments_styles
+      Paperclip.save_current_attachments_styles!
+      assert_equal Hash.new, Paperclip.missing_attachments_styles
+    end
+
+    # It's impossible to build styles hash without loading from database whole bunch of records
+    should "skip lambda-styles" do
+      rebuild_model :styles => lambda{ |attachment| attachment.instance.other == 'a' ? {:thumb => "50x50#"} : {:large => "400x400"} }
+      assert_equal Hash.new, Paperclip.send(:current_attachments_styles)
+    end
+
+  end
+
+end