zammad/app/models/store/provider/file.rb

# Copyright (C) 2012-2014 Zammad Foundation, http://zammad-foundation.org/

class Store
  module Provider
    module File

      def self.add(data, sha)
        write_to_fs(data, sha)
        true
      end

      def self.get(sha)
        read_from_fs(sha)
      end

      def self.delete(sha)
        unlink_from_fs(sha)
      end

      private

      # generate file location
      def self.get_locaton(sha)

        # generate directory
        base = Rails.root.to_s + '/storage/fs/'
        parts = sha.scan(/.{1,4}/)
        path = parts[ 1 .. 10 ].join('/') + '/'
        file = parts[ 11 .. parts.count ].join('')
        location = "#{base}/#{path}"

        # create directory if not exists
        if !File.exist?( location )
          FileUtils.mkdir_p( location )
        end
        location += file
      end

      # unlink file from fs
      def self.unlink_from_fs(sha)
        if File.exist?( get_locaton(sha) )
          puts "NOTICE: storge remove '#{ get_locaton(sha) }'"
          File.delete( get_locaton(sha) )
        end
      end

      # read file from fs
      def self.read_from_fs(sha)
        puts "read from fs #{ get_locaton(sha) }"
        if !File.exist?( get_locaton(sha) )
          raise "ERROR: No such file #{ get_locaton(sha) }"
        end
        data = File.open( get_locaton(sha), 'rb' )
        content = data.read

        # check sha
        local_sha = Digest::SHA256.hexdigest( content )
        if local_sha != sha
          raise "ERROR: Corrupt file in fs #{ get_locaton(sha) }, sha should be #{sha} but is #{local_sha}"
        end
        content
      end

      # write file to fs
      def self.write_to_fs(data, sha)

        # install file
        permission = '600'
        if !File.exist?( get_locaton(sha) )
          puts "NOTICE: storge write '#{ get_locaton(sha) }' (#{permission})"
          file = File.new( get_locaton(sha), 'wb' )
          file.write( data )
          file.close
        end
        File.chmod( permission.to_i(8), get_locaton(sha) )

        # check sha
        local_sha = Digest::SHA256.hexdigest( read_from_fs(sha) )
        if sha != local_sha
          raise "ERROR: Corrupt file in fs #{ get_locaton(sha) }, sha should be #{sha} but is #{local_sha}"
        end

        true
      end
    end
  end
end