selectively reprocessing attachment styles

lib/paperclip/attachment.rb

@@ -241,7 +241,7 @@ module Paperclip
     # in the paperclip:refresh rake task and that's it. It will regenerate all
     # thumbnails forcefully, by reobtaining the original file and going through
     # the post-process again.
-    def reprocess!
+    def reprocess!(*style_args)
       new_original = Tempfile.new("paperclip-reprocess")
       new_original.binmode
       if old_original = to_file(:original)
@@ -249,7 +249,7 @@ module Paperclip
         new_original.rewind
 
         @queued_for_write = { :original => new_original }
-        post_process
+        post_process(*style_args)
 
         old_original.close if old_original.respond_to?(:close)
 
@@ -324,21 +324,23 @@ module Paperclip
       [ style_options, all_options ].compact.join(" ")
     end
 
-    def post_process #:nodoc:
+    def post_process(*style_args) #:nodoc:
       return if @queued_for_write[:original].nil?
       instance.run_paperclip_callbacks(:post_process) do
         instance.run_paperclip_callbacks(:"#{name}_post_process") do
-          post_process_styles
+          post_process_styles(*style_args)
         end
       end
     end
 
-    def post_process_styles #:nodoc:
+    def post_process_styles(*style_args) #:nodoc:
       styles.each do |name, style|
         begin
-          raise RuntimeError.new("Style #{name} has no processors defined.") if style.processors.blank?
-          @queued_for_write[name] = style.processors.inject(@queued_for_write[:original]) do |file, processor|
-            Paperclip.processor(processor).make(file, style.processor_options, self)
+          if style_args.empty? || style_args.include?(name)
+            raise RuntimeError.new("Style #{name} has no processors defined.") if style.processors.blank?
+            @queued_for_write[name] = style.processors.inject(@queued_for_write[:original]) do |file, processor|
+              Paperclip.processor(processor).make(file, style.processor_options, self)
+            end
           end
         rescue PaperclipError => e
           log("An error was received while processing: #{e.inspect}")

test/integration_test.rb

@@ -69,6 +69,78 @@ class IntegrationTest < Test::Unit::TestCase
     end
   end
 
+  context "Attachment" do
+    setup do
+      @thumb_path = "./test/../public/system/avatars/1/thumb/5k.png"
+      File.delete(@thumb_path) if File.exists?(@thumb_path)
+      rebuild_model :styles => { :thumb => "50x50#" }
+      @dummy = Dummy.new
+      @file = File.new(File.join(File.dirname(__FILE__),
+                                 "fixtures",
+                                 "5k.png"), 'rb')
+
+    end
+
+    teardown { @file.close }
+
+    should "not create the thumbnails upon saving when post-processing is disabled" do
+      @dummy.avatar.post_processing = false
+      @dummy.avatar = @file
+      assert @dummy.save
+      assert !File.exists?(@thumb_path)
+    end
+
+    should "create the thumbnails upon saving when post_processing is enabled" do
+      @dummy.avatar.post_processing = true
+      @dummy.avatar = @file
+      assert @dummy.save
+      assert File.exists?(@thumb_path)
+    end
+  end
+
+  context "Attachment with no generated thumbnails" do
+    setup do
+      @thumb_small_path = "./test/../public/system/avatars/1/thumb_small/5k.png"
+      @thumb_large_path = "./test/../public/system/avatars/1/thumb_large/5k.png"
+      File.delete(@thumb_small_path) if File.exists?(@thumb_small_path)
+      File.delete(@thumb_large_path) if File.exists?(@thumb_large_path)
+      rebuild_model :styles => { :thumb_small => "50x50#", :thumb_large => "60x60#" }
+      @dummy = Dummy.new
+      @file = File.new(File.join(File.dirname(__FILE__),
+                                 "fixtures",
+                                 "5k.png"), 'rb')
+
+      @dummy.avatar.post_processing = false
+      @dummy.avatar = @file
+      assert @dummy.save
+      @dummy.avatar.post_processing = true
+    end
+
+    teardown { @file.close }
+
+    should "allow us to create all thumbnails in one go" do
+      assert !File.exists?(@thumb_small_path)
+      assert !File.exists?(@thumb_large_path)
+
+      @dummy.avatar.reprocess!
+
+      assert File.exists?(@thumb_small_path)
+      assert File.exists?(@thumb_large_path)
+    end
+
+    should "allow us to selectively create each thumbnail" do
+      assert !File.exists?(@thumb_small_path)
+      assert !File.exists?(@thumb_large_path)
+
+      @dummy.avatar.reprocess! :thumb_small
+      assert File.exists?(@thumb_small_path)
+      assert !File.exists?(@thumb_large_path)
+
+      @dummy.avatar.reprocess! :thumb_large
+      assert File.exists?(@thumb_large_path)
+    end
+  end
+
   context "A model that modifies its original" do
     setup do
       rebuild_model :styles => { :original => "2x2#" }