Class: Zermelo::Backends::Redis

Inherits:
Object
  • Object
show all
Includes:
Zermelo::Backend
Defined in:
lib/zermelo/backends/redis.rb

Instance Method Summary collapse

Methods included from Zermelo::Backend

#add, #clear, #delete, #escape_key_name, #get, #index_keys, #lock, #move, #purge, #safe_value, #set, #unescape_key_name

Instance Method Details

#abort_transaction ⇒ Object 



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# File 'lib/zermelo/backends/redis.rb', line 114

def abort_transaction
  return false if @transaction_redis.nil?
  @transaction_redis.discard
  @transaction_redis = nil
  @changes = []
  true
end

#begin_transaction ⇒ Object 



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# File 'lib/zermelo/backends/redis.rb', line 97

def begin_transaction
  return false unless @transaction_redis.nil?
  @transaction_redis = Zermelo.redis
  @transaction_redis.multi
  @changes = []
  true
end

#commit_transaction ⇒ Object 



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# File 'lib/zermelo/backends/redis.rb', line 105

def commit_transaction
  return false if @transaction_redis.nil?
  apply_changes(@changes)
  @transaction_redis.exec
  @transaction_redis = nil
  @changes = []
  true
end

#filter(ids_key, associated_class, callback_target_class = nil, callback_target_id = nil, callbacks = nil, sort_order = nil) ⇒ Object

def default_sorted_set_key

:timestamp

end



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# File 'lib/zermelo/backends/redis.rb', line 19

def filter(ids_key, associated_class, callback_target_class = nil,
  callback_target_id = nil, callbacks = nil, sort_order = nil)

  Zermelo::Filters::Redis.new(self, ids_key, associated_class,
                              callback_target_class, callback_target_id,
                              callbacks, sort_order)
end

#get_multiple(*attr_keys) ⇒ Object 



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# File 'lib/zermelo/backends/redis.rb', line 27

def get_multiple(*attr_keys)
  attr_keys.inject({}) do |memo, attr_key|
    redis_attr_key = key_to_redis_key(attr_key)

    class_key = attr_key.klass.send(:class_key)

    memo[class_key] ||= {}
    memo[class_key][attr_key.id] ||= {}
    memo[class_key][attr_key.id][attr_key.name.to_s] = if Zermelo::COLLECTION_TYPES.has_key?(attr_key.type)

      case attr_key.type
      when :list
        if attr_key.accessor.nil?
          Zermelo.redis.lrange(redis_attr_key, 0, -1)
        else
          # TODO
        end
      when :set
        if attr_key.accessor.nil?
          Set.new( Zermelo.redis.smembers(redis_attr_key) )
        else
          # TODO
        end
      when :hash
        if attr_key.accessor.nil?
          Zermelo.redis.hgetall(redis_attr_key)
        else
          # TODO
        end
      when :sorted_set
        if attr_key.accessor.nil?
          Zermelo::OrderedSet.new(Zermelo.redis.zrange(redis_attr_key, 0, -1))
        else
          # TODO
        end
      end

    else
      value = Zermelo.redis.hget(redis_attr_key, attr_key.name.to_s)

      if value.nil?
        nil
      else
        case attr_key.type
        when :string
          value.to_s
        when :integer
          value.to_i
        when :float
          value.to_f
        when :timestamp
          Time.at(value.to_f)
        when :boolean
          case value
          when TrueClass
            true
          when FalseClass
            false
          when String
            'true'.eql?(value.downcase)
          else
            nil
          end
        end
      end
    end
    memo
  end
end

#index_lookup(att, associated_class, idx_class, value, attr_type, temp_keys) ⇒ Object

TODO converge usage of idx_class and _index lookup invocation



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# File 'lib/zermelo/backends/redis.rb', line 158

def index_lookup(att, associated_class, idx_class, value, attr_type, temp_keys)
  if (idx_class == Zermelo::Associations::RangeIndex) && !value.is_a?(Zermelo::Filters::IndexRange)
    raise "Range index must be passed a range"
  end

  case value
  when Regexp
    raise "Can't query non-string values via regexp" unless :string.eql?(attr_type)

    idx_key = associated_class.send(:temp_key, :set)
    temp_keys << idx_key
    idx_result = key_to_redis_key(idx_key)

    starts_with_string_re = /^string:/
    case idx_class.name
    when 'Zermelo::Associations::UniqueIndex'
      index_key = key_to_redis_key(Zermelo::Records::Key.new(
        :klass  => associated_class,
        :name   => "by_#{att}",
        :type   => :hash,
        :object => :index
      ))
      candidates = Zermelo.redis.hgetall(index_key)
      matching_ids = candidates.values_at(*candidates.keys.select {|k|
        (starts_with_string_re === k) &&
          (value === unescape_key_name(k.sub(starts_with_string_re, '')))
      })
      Zermelo.redis.sadd(idx_result, matching_ids) unless matching_ids.empty?
    when 'Zermelo::Associations::Index'
      key_root = key_to_redis_key(Zermelo::Records::Key.new(
        :klass  => associated_class,
        :name   => "by_#{att}:string",
        :type   => :set,
        :object => :index
      ))

      key_pat = "#{key_root}:?*"

      matching_sets = if (Zermelo.redis_version.split('.') <=> ['2', '8', '0']) == 1
        # lock will be subsumed by outer lock if present -- required to
        # know that scan is getting consistent results
        associated_class.lock do
          Zermelo.redis.scan_each(:match => key_pat).to_a
        end
      else
        # SCAN is only supported in Redis >= 2.8.0
        Zermelo.redis.keys(key_pat)
      end

      matching_sets.select! do |k|
        k =~ /^#{key_root}:(.+)$/
        value === $1
      end

      Zermelo.redis.sunionstore(idx_result, matching_sets) unless matching_sets.empty?
    end
    idx_key
  else
    index = associated_class.send("#{att}_index")

    case index
    when Zermelo::Associations::RangeIndex
      r_index_key = key_to_redis_key(index.key)
      range = if value.by_score
        range_start  = value.start.nil?  ? '-inf' : safe_value(attr_type, value.start)
        range_finish = value.finish.nil? ? '+inf' : safe_value(attr_type, value.finish)
        Zermelo.redis.zrangebyscore(r_index_key, range_start, range_finish)
      else
        range_start  = value.start  ||  0
        range_finish = value.finish || -1
        Zermelo.redis.zrange(r_index_key, range_start, range_finish)
      end

      # TODO another way for index_lookup to indicate 'empty result', rather
      # than creating & returning an empty key
      idx_key = associated_class.send(:temp_key, :set)
      temp_keys << idx_key
      Zermelo.redis.sadd(key_to_redis_key(idx_key), range) unless range.empty?
      idx_key
    when Zermelo::Associations::UniqueIndex
      idx_key = associated_class.send(:temp_key, :set)
      temp_keys << idx_key

      Zermelo.redis.sadd(key_to_redis_key(idx_key),
        Zermelo.redis.hget(key_to_redis_key(index.key),
                           index_keys(attr_type, value).join(':')))
      idx_key
    when Zermelo::Associations::Index
      index.key(value)
    end
  end
end

#key_to_redis_key(key) ⇒ Object 



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# File 'lib/zermelo/backends/redis.rb', line 122

def key_to_redis_key(key)
  class_key = key.klass.send(:class_key)

  obj = case key.object
  when :attribute
    'attrs'
  when :association
    'assocs'
  when :index
    'indices'
  when :temporary
    'tmp'
  end

  name = Zermelo::COLLECTION_TYPES.has_key?(key.type) ? ":#{key.name}" : ''

  "#{class_key}:#{key.id.nil? ? '' : key.id}:#{obj}#{name}"
end

#temp_key_wrap ⇒ Object 



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# File 'lib/zermelo/backends/redis.rb', line 141

def temp_key_wrap
  return unless block_given?
  temp_keys = []
  begin
    yield(temp_keys)
  rescue
    raise
  ensure
    unless temp_keys.empty?
      Zermelo.redis.del(*temp_keys.collect {|tk| key_to_redis_key(tk)})
      temp_keys.clear
    end
  end
end