dpn-admin/dpn-bagit

require 'bagit'

module BagIt
    module Validity
        def consistent?
            (manifest_files|tagmanifest_files).each do |mf|
                # get the algorithm implementation
                readAlgo = /manifest-(.+).txt$/.match(File.basename(mf))[1]
                algo = case readAlgo
                          when /sha1/i
                              Digest::SHA1
                          when /md5/i
                              Digest::MD5
                          when /sha256/i
                              Digest::SHA256
                          when /sha384/i
                              Digest::SHA384
                          when /sha512/i
                              Digest::SHA512
                          else
                              errors.add :consistency, "Algorithm #{readAlgo} is invalid or unsupported."
                              return false
                      end
                # Check every file in the manifest
                File.open(mf) do |io|
                    io.each_line do |line|
                        expected, path = line.chomp.split(/\s+/, 2)
                        file = File.join(bag_dir, path)
                        if File.exist? file
                            actual = algo.file(file).hexdigest
                            if expected != actual
                                errors.add :consistency, "expected #{file} to have #{algo}: #{expected}, actual is #{actual}"
                            end
                        end
                    end
                end
            end


            errors.on(:consistency).nil?
        end
    end
end