# File lib/fog/aws/requests/storage/head_object.rb, line 27
        def head_object(bucket_name, object_name, options={})
          unless bucket_name
            raise ArgumentError.new('bucket_name is required')
          end
          unless object_name
            raise ArgumentError.new('object_name is required')
          end
          if version_id = options.delete('versionId')
            query = {'versionId' => version_id}
          end
          headers = {}
          headers['If-Modified-Since'] = Fog::Time.at(options['If-Modified-Since'].to_i).to_date_header if options['If-Modified-Since']
          headers['If-Unmodified-Since'] = Fog::Time.at(options['If-Unmodified-Since'].to_i).to_date_header if options['If-Modified-Since']
          headers.merge!(options)
          request({
            :expects    => 200,
            :headers    => headers,
            :bucket_name => bucket_name,
            :object_name => object_name,
            :idempotent => true,
            :method     => 'HEAD',
            :query      => query
          })
        end