Add in a helper for parsing source URLs
user
```ruby
#
# Cookbook Name:: pdns
# Libraries:: helpers
#
# Copyright 2014, Aetrion, LLC.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

def pdns_file(uri)
  require 'pathname'
  require 'uri'
  Pathname.new(URI.parse(uri).path).basename.to_s
end
```
assistant