Add a picture validation for duplicate filenames. Ensure the picture …

…is valid before redirecting or responding in the picture controller.

app/controllers/pictures_controller.rb

@@ -55,12 +55,14 @@ def update
 
     # Since both albums and recipes contain pictures we need some special redirect/response logic.
     def respond_or_redirect
-      if (@picture.imageable_type == 'Album')
-        redirect_to(album_path(@picture.imageable_id))
-        return
-      elsif (@picture.imageable_type == 'Recipe')
-        redirect_to(recipe_path(@picture.imageable_id))
-        return
+      if(@picture.valid?)
+        if (@picture.imageable_type == 'Album')
+          redirect_to(album_path(@picture.imageable_id))
+          return
+        elsif (@picture.imageable_type == 'Recipe')
+          redirect_to(recipe_path(@picture.imageable_id))
+          return
+        end
       end
       respond_with(@picture)
     end

app/models/picture.rb

@@ -10,6 +10,8 @@ class Picture < ActiveRecord::Base
 
   validates_size_of   :data, :maximum => 3.megabyte, :message => 'cannot be greater than 3mb'
 
+  validate :picture_doesnt_exist
+
   def uploaded_picture=(picture_field)
     self.name         = base_part_of(picture_field.original_filename)
     self.content_type = picture_field.content_type.chomp
@@ -26,4 +28,10 @@ def base_part_of(file_name)
   def picture_contains_data
     errors.add('Picture data', 'must not be blank') unless !self.data.blank?
   end
+
+  def picture_doesnt_exist
+    if (Picture.find_by_name(self.name))
+      errors.add('A picture with this filename', 'already exists')
+    end
+  end
 end