Added paperclip:refresh:metadata and :thumbnails tasks, and a paperclip:refresh…

Added paperclip:refresh:metadata and :thumbnails tasks, and a paperclip:refresh task to tie them together. Also, paperclip:clean checks validity of the attachment, not the whole model instance.

tasks/paperclip_tasks.rake

@@ -33,11 +33,28 @@ def for_all_attachments
 end
 
 namespace :paperclip do
-  desc "Regenerates thumbnails for a given CLASS (and optional ATTACHMENT)"
-  task :refresh => :environment do
-    for_all_attachments do |instance, name|
-      instance.send(name).reprocess!
-      instance.send(name).save
+  desc "Refreshes both metadata and thumbnails."
+  task :refresh => ["paperclip:refresh:metadata", "paperclip:refresh:thumbnails"]
+
+  namespace :refresh do
+    desc "Regenerates thumbnails for a given CLASS (and optional ATTACHMENT)."
+    task :thumbnails => :environment do
+      for_all_attachments do |instance, name|
+        instance.send(name).reprocess!
+      end
+    end
+
+    desc "Regenerates content_type/size metadata for a given CLASS (and optional ATTACHMENT)."
+    task :metadata => :environment do
+      for_all_attachments do |instance, name|
+        if file = instance.send(name).to_file
+          instance.send("#{name}_content_type=", file.content_type)
+          instance.send("#{name}_file_size=", file.size)
+          instance.save(false)
+        else
+          true
+        end
+      end
     end
   end
 
@@ -45,7 +62,7 @@ namespace :paperclip do
   task :clean => :environment do
     for_all_attachments do |instance, name|
       instance.send(name).send(:validate)
-      if instance.valid?
+      if instance.send(name).valid?
         true
       else
         instance.send("#{name}=", nil)