redis_copy.rb

def dump_redis(redis, keys)
  values = {}
  keys.each do |key|
    case type = redis.type(key)
    when "hash"
      values[key] = redis.hgetall(key)
    when "set"
      values[key] = Set.new(redis.smembers(key))
    when "list"
      values[key] = redis.lrange(key, 0, -1)
    when "string"
      values[key] = redis.get(key).to_s
    else
      raise "Don't know how to copy: #{type.inspect}"
    end
  end
  values
end

def load_redis(redis, keys_and_values)
  keys_and_values.each do |key, value|
    case value
    when Hash
      redis.hmset(key, *value.to_a)
    when Set
      redis.sadd(key, value)
    when Array
      redis.lpush(key, value.reverse)
    when String
      redis.set(key, value)
    else
      raise "Don't know how to copy: #{value.class}"
    end
  end
end