evil_type.rb

require 'uri'

module Puppet
  newtype(:uri_provider) do
    @doc = "A type which determines its provider based on the scheme of a URI passed as a parameter"
    
    ensurable

    newparam(:name) do
    end
    
    newparam(:uri) do
      desc "The URI we should attempt to provide for"
    end

    def self.fixup_default_provider
      @paramhash[:provider].defaultto {
        uri = URI(@resource[:uri])
        uri.scheme
      }
    end

    # Normally providify gets called automatically when a
    # provider is added for a type. We call it explicitly
    # here so that we know for sure that the parameter
    # exists before we try to change it.
    providify
    fixup_default_provider
  end
end