Ensure correct extension when downloading documents

plugins/documents/app/controllers/documents_controller.rb

@@ -54,10 +54,6 @@ def destroy
 
   def show
     @document = Document.find(params[:id])
-    filename = @document.name
-    unless filename.include? '.'
-      filename += '.' + MIME::Types[@document.mime].first.preferred_extension
-    end
-    send_data(@document.data, :filename => filename, :type => @document.mime)
+    send_data(@document.data, filename: @document.filename, type: @document.mime)
   end
 end

plugins/documents/app/models/document.rb

@@ -2,4 +2,19 @@ class Document < ActiveRecord::Base
   belongs_to :created_by, :class_name => 'User', :foreign_key => 'created_by_user_id'
 
   validates_presence_of :data
+
+  def filename
+    types = MIME::Types[mime]
+
+    if name.include? '.'
+      types.each do |type|
+        type.extensions.each do |extension|
+          return name if name.end_with? ".#{extension}"
+        end
+      end
+    end
+
+    "#{name}.#{types.first.preferred_extension}"
+  end
+
 end