Move extension logic to SecureUploader class

app/uploaders/exported_photos.rb

@@ -14,10 +14,6 @@ class ExportedPhotos < SecureUploader
   end
 
   def filename
-    return if original_filename.blank?
-
-    filename_parts = original_filename.split(".")
-    extensions = filename_parts.join(".")
-    "#{model.username}_photos_#{secure_token}.#{extensions}" if original_filename.present?
+    "diaspora_#{model.username}_photos_#{secure_token}#{extension}"
   end
 end

app/uploaders/exported_user.rb

@@ -14,10 +14,6 @@ class ExportedUser < SecureUploader
   end
 
   def filename
-    return if original_filename.blank?
-
-    filename_parts = original_filename.split(".")
-    extensions = filename_parts.join(".")
-    "#{model.username}_data_#{secure_token}.#{extensions}"
+    "diaspora_#{model.username}_data_#{secure_token}#{extension}"
   end
 end

app/uploaders/secure_uploader.rb

@@ -3,6 +3,10 @@
 class SecureUploader < CarrierWave::Uploader::Base
   protected
 
+  def extension
+    ".#{original_filename.split('.').drop(1).join('.')}" if original_filename.present?
+  end
+
   def secure_token(bytes=16)
     var = :"@#{mounted_as}_secure_token"
     model.instance_variable_get(var) or model.instance_variable_set(var, SecureRandom.urlsafe_base64(bytes))

spec/models/user_spec.rb

@@ -976,13 +976,14 @@ describe User, type: :model do
   end
 
   describe "#export" do
-    it "doesn't change the filename when the user is saved" do
+    it "doesn't change the url when the user is saved" do
       user = FactoryBot.create(:user)
 
-      filename = user.export.filename
+      user.perform_export!
+      url = user.export.url
       user.save!
 
-      expect(User.find(user.id).export.filename).to eq(filename)
+      expect(User.find(user.id).export.url).to eq(url)
     end
   end