added :preserve_files option so paperclip can get along with soft-delete plugins…

added :preserve_files option so paperclip can get along with soft-delete plugins like acts_as_paranoid

Closes #152

lib/paperclip/attachment.rb

@@ -21,7 +21,8 @@ module Paperclip
         :whiny                 => Paperclip.options[:whiny] || Paperclip.options[:whiny_thumbnails],
         :use_default_time_zone => true,
         :hash_digest           => "SHA1",
-        :hash_data             => ":class/:attachment/:id/:style/:updated_at"
+        :hash_data             => ":class/:attachment/:id/:style/:updated_at",
+        :preserve_files        => false
       }
     end
 
@@ -55,6 +56,7 @@ module Paperclip
       @hash_secret           = options[:hash_secret]
       @convert_options       = options[:convert_options]
       @processors            = options[:processors]
+      @preserve_files        = options[:preserve_files]
       @options               = options
       @post_processing       = true
       @queued_for_delete     = []
@@ -175,9 +177,11 @@ module Paperclip
     # nil to the attachment *and saving*. This is permanent. If you wish to
     # wipe out the existing attachment but not save, use #clear.
     def destroy
+      unless @preserve_files
         clear
         save
       end
+    end
 
     # Returns the name of the file as originally assigned, and lives in the
     # <attachment>_file_name attribute of the model.
@@ -366,7 +370,7 @@ module Paperclip
     end
 
     def queue_existing_for_delete #:nodoc:
-      return unless file?
+      return unless (file? && @preserve_files==false)
       @queued_for_delete += [:original, *styles.keys].uniq.map do |style|
         path(style) if exists?(style)
       end.compact

test/attachment_test.rb

@@ -998,4 +998,27 @@ class AttachmentTest < Test::Unit::TestCase
       end
     end
   end
+  
+  context "an attachment with delete_file option set to false" do
+    setup do
+      rebuild_model :preserve_files => true
+      @dummy = Dummy.new
+      @file = File.new(File.join(File.dirname(__FILE__), "fixtures", "5k.png"), 'rb')
+      @dummy.avatar = @file
+      @dummy.save!
+      @attachment = @dummy.avatar 
+      @path = @attachment.path      
+    end
+    
+    should "not delete the files from storage when attachment is destroyed" do      
+      @attachment.destroy
+      assert File.exists?(@path)
+    end
+    
+    should "not dleete the file when model is destroy" do
+      @dummy.destroy
+      assert File.exists?(@path)
+    end
+  end
+
 end