File Copy

Source.io reads String chunks from an IO-like object. Sink.io writes String chunks to an IO-like object. Both require a scheduler-backed non-blocking fiber.

ruby

require "async"
require "fiber_stream"

chunks_written =
  Async do
    input = File.open("input.txt", "rb")
    output = File.open("output.txt", "wb")

    FiberStream::Source.io(input, chunk_size: 16 * 1024, close: true)
      .map(&:upcase)
      .run_with(FiberStream::Sink.io(output, close: true, flush: true))
  end.wait

Use close: true when FiberStream should close the IO object after the stream finishes or fails.

chunk_size is the maximum byte count passed to readpartial for one pull. Choose a bounded value for the workload. Very large values may cause the IO implementation to attempt large allocations.

The runnable version is examples/file_copy.rb.

File Copy ​

File Copy