Class: IntervalResponse::RackBodyWrapper

Inherits:
Object
  • Object
show all
Defined in:
lib/interval_response/rack_body_wrapper.rb

Overview

The Rack body wrapper is intended to be returned as the third element of the Rack response triplet. It supports the #each method and will call to the IntervalResponse object given to it at instantiation, filling up a pre-allocated String object with the bytes to be served out. The String object will then be repeatedly yielded to the Rack webserver with the response data. Since Ruby strings are mutable, the String object will be sized to a certain capacity and reused across calls to save allocations.

Constant Summary collapse

CHUNK_SIZE =

Default size of the chunk (String buffer) which is going to be yielded to the caller of the ‘each` method. Set toroughly one TCP kernel buffer

65 * 1024

Instance Method Summary collapse

Constructor Details

#initialize(with_interval_response, chunk_size:) ⇒ RackBodyWrapper

Returns a new instance of RackBodyWrapper.



15
16
17
18
 
# File 'lib/interval_response/rack_body_wrapper.rb', line 15

def initialize(with_interval_response, chunk_size:)
  @chunk_size = chunk_size
  @interval_response = with_interval_response
end

Instance Method Details

#each ⇒ Object 



20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
 
# File 'lib/interval_response/rack_body_wrapper.rb', line 20

def each
  buf = String.new(capacity: @chunk_size)
  @interval_response.each do |segment, range_in_segment|
    case segment
    when IntervalResponse::LazyFile
      segment.with do |file_handle|
        with_each_chunk(range_in_segment) do |offset, read_n|
          file_handle.seek(offset, IO::SEEK_SET)
          yield file_handle.read(read_n, buf)
        end
      end
    when String
      with_each_chunk(range_in_segment) do |offset, read_n|
        yield segment.slice(offset, read_n)
      end
    when IO, Tempfile
      with_each_chunk(range_in_segment) do |offset, read_n|
        segment.seek(offset, IO::SEEK_SET)
        yield segment.read(read_n, buf)
      end
    else
      raise TypeError, "RackBodyWrapper only supports IOs or Strings"
    end
  end
ensure
  buf.clear
end