Added before and after post_process hooks

lib/paperclip.rb

@@ -150,6 +150,9 @@ module Paperclip
       after_save :save_attached_files
       before_destroy :destroy_attached_files
 
+      define_callbacks :before_post_process, :after_post_process
+      define_callbacks :"before_#{name}_post_process", :"after_#{name}_post_process"
+     
       define_method name do |*args|
         a = attachment_for(name)
         (args.length > 0) ? a.to_s(args.first) : a

lib/paperclip/attachment.rb

@@ -15,7 +15,7 @@ module Paperclip
       }
     end
 
-    attr_reader :name, :instance, :styles, :default_style, :convert_options
+    attr_reader :name, :instance, :styles, :default_style, :convert_options, :queued_for_write
 
     # Creates an Attachment object. +name+ is the name of the attachment, +instance+ is the
     # ActiveRecord object instance it's attached to, and +options+ is the same as the hash
@@ -272,6 +272,8 @@ module Paperclip
 
     def post_process #:nodoc:
       return if @queued_for_write[:original].nil?
+      return if callback(:before_post_process) == false
+      return if callback(:"before_#{name}_post_process") == false
       logger.info("[paperclip] Post-processing #{name}")
       @styles.each do |name, args|
         begin
@@ -286,6 +288,12 @@ module Paperclip
           (@errors[:processing] ||= []) << e.message if @whiny_thumbnails
         end
       end
+      callback(:"after_#{name}_post_process")
+      callback(:after_post_process)
+    end
+
+    def callback which
+      instance.run_callbacks(which, @queued_for_write){|result, obj| result == false }
     end
 
     def interpolate pattern, style = default_style #:nodoc:

test/attachment_test.rb

@@ -147,29 +147,82 @@ class AttachmentTest < Test::Unit::TestCase
     end
   end
 
+  context "Assigning an attachment with post_process hooks" do
+    setup do
+      rebuild_model :styles => { :something => "100x100#" }
+      Dummy.class_eval do
+        before_avatar_post_process :do_before_avatar
+        after_avatar_post_process :do_after_avatar
+        before_post_process :do_before_all
+        after_post_process :do_after_all
+        def do_before_avatar; end
+        def do_after_avatar; end
+        def do_before_all; end
+        def do_after_all; end
+      end
+      @file  = File.new(File.join(FIXTURES_DIR, "5k.png"), 'rb')
+      @file.stubs(:to_tempfile).returns(@file)
+      @dummy = Dummy.new
+      Paperclip::Thumbnail.stubs(:make).returns(@file)
+      @attachment = @dummy.avatar
+    end
+
+    should "call the defined callbacks when assigned" do
+      @dummy.expects(:do_before_avatar).with()
+      @dummy.expects(:do_after_avatar).with()
+      @dummy.expects(:do_before_all).with()
+      @dummy.expects(:do_after_all).with()
+      Paperclip::Thumbnail.expects(:make).returns(@file)
+      @dummy.avatar = @file
+    end
+
+    should "not cancel the processing if a before_post_process returns nil" do
+      @dummy.expects(:do_before_avatar).with().returns(nil)
+      @dummy.expects(:do_after_avatar).with()
+      @dummy.expects(:do_before_all).with().returns(nil)
+      @dummy.expects(:do_after_all).with()
+      Paperclip::Thumbnail.expects(:make).returns(@file)
+      @dummy.avatar = @file
+    end
+
+    should "cancel the processing if a before_post_process returns false" do
+      @dummy.expects(:do_before_avatar).never
+      @dummy.expects(:do_after_avatar).never
+      @dummy.expects(:do_before_all).with().returns(false)
+      @dummy.expects(:do_after_all).never
+      Paperclip::Thumbnail.expects(:make).never
+      @dummy.avatar = @file
+    end
+
+    should "cancel the processing if a before_avatar_post_process returns false" do
+      @dummy.expects(:do_before_avatar).with().returns(false)
+      @dummy.expects(:do_after_avatar).never
+      @dummy.expects(:do_before_all).with().returns(true)
+      @dummy.expects(:do_after_all).never
+      Paperclip::Thumbnail.expects(:make).never
+      @dummy.avatar = @file
+    end
+  end
+
   context "Assigning an attachment" do
     setup do
-      rebuild_model
-      
-      @not_file = mock
-      @not_file.stubs(:nil?).returns(false)
-      @not_file.expects(:to_tempfile).returns(self)
-      @not_file.expects(:original_filename).returns("filename.png\r\n")
-      @not_file.expects(:content_type).returns("image/png\r\n")
-      @not_file.expects(:size).returns(10).times(2)
-      
+      rebuild_model :styles => { :something => "100x100#" }
+      @file  = File.new(File.join(FIXTURES_DIR, "5k.png"), 'rb')
+      @file.expects(:original_filename).returns("5k.png\n\n")
+      @file.expects(:content_type).returns("image/png\n\n")
+      @file.stubs(:to_tempfile).returns(@file)
       @dummy = Dummy.new
+      Paperclip::Thumbnail.expects(:make).returns(@file)
+      @dummy.expects(:run_callbacks).with(:before_avatar_post_process, {:original => @file})
+      @dummy.expects(:run_callbacks).with(:before_post_process, {:original => @file})
+      @dummy.expects(:run_callbacks).with(:after_avatar_post_process, {:original => @file, :something => @file})
+      @dummy.expects(:run_callbacks).with(:after_post_process, {:original => @file, :something => @file})
       @attachment = @dummy.avatar
-      @attachment.expects(:valid_assignment?).with(@not_file).returns(true)
-      @attachment.expects(:queue_existing_for_delete)
-      @attachment.expects(:post_process)
-      @attachment.expects(:valid?).returns(true)
-      @attachment.expects(:validate)
-      @dummy.avatar = @not_file
+      @dummy.avatar = @file
     end
 
     should "strip whitespace from original_filename field" do
-      assert_equal "filename.png", @dummy.avatar.original_filename
+      assert_equal "5k.png", @dummy.avatar.original_filename
     end
 
     should "strip whitespace from content_type field" do