Contents

module Backend

  class Redis

    # Redis Backend Accessor.
    #
    # Provides necessary helper methods for its
    # subclasses.
    # Not directly useable, as it does not provide
    # dump/load methods.
    #
    class Basic

      attr_reader :namespace, :backend

      # An index cache takes a path, without file extension,
      # which will be provided by the subclasses.
      #
      def initialize namespace
        @namespace = namespace

        # TODO Turn this inside out such that people can pass in
        # their own Redis instance.
        #
        # TODO Make the :db a real option.
        #
        @backend = ::Redis.new :db => 15
      end

      # Does nothing.
      #
      def load
        # Nothing.
      end
      # We do not use Redis to retrieve data.
      #
      def retrieve
        # Nothing.
      end

      # Redis does not backup.
      #
      def backup
        # Nothing.
      end

      # Deletes the Redis index namespace.
      #
      def delete
        # Not implemented here.
        # Note: backend.flushdb might be the way to go,
        #       but since we cannot delete by key pattern,
        #       we don't do anything.
      end

      # Checks.
      #

      # Is this cache suspiciously small?
      #
      def cache_small?
        size < 1
      end

      # Is the cache ok?
      #
      # A small cache is still ok.
      #
      def cache_ok?
        size > 0
      end

      # Extracts the size of the file in Bytes.
      #
      # Note: This is a very forgiving implementation.
      #       But as long as Redis does not implement
      #       DBSIZE KEYPATTERN, we are stuck with this.
      #
      def size
        backend.dbsize
      end

      #
      #
      def to_s
        "#{self.class}(#{namespace}:*)"
      end

    end

  end

end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
picky-2.7.0	lib/picky/backend/redis/basic.rb