Class: Rainbows::DevFdResponse

Inherits:
Struct
  • Object
show all
Includes:
Rack::Utils
Defined in:
lib/rainbows/dev_fd_response.rb

Overview

Rack response middleware wrapping any IO-like object with an OS-level file descriptor associated with it. May also be used to create responses from integer file descriptors or existing IO objects. This may be used in conjunction with the #to_path method on servers that support it to pass arbitrary file descriptors into the HTTP response without additional open(2) syscalls

Defined Under Namespace

Classes: Body

Constant Summary collapse

FD_MAP =

:stopdoc:

Rainbows::FD_MAP

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#app ⇒ Object

Returns the value of attribute app

Returns:

  • (Object) —

    the current value of app



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# File 'lib/rainbows/dev_fd_response.rb', line 10

def app
  @app
end

Instance Method Details

#call(env) ⇒ Object

Rack middleware entry point, we’ll just pass through responses unless they respond to to_io or to_path



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# File 'lib/rainbows/dev_fd_response.rb', line 18

def call(env)
  status, headers, body = response = app.call(env)

  # totally uninteresting to us if there's no body
  if STATUS_WITH_NO_ENTITY_BODY.include?(status.to_i) ||
     File === body ||
     (body.respond_to?(:to_path) && File.file?(body.to_path))
    return response
  end

  io = body.to_io if body.respond_to?(:to_io)
  io ||= File.open(body.to_path) if body.respond_to?(:to_path)
  return response if io.nil?

  headers = Rack::Utils::HeaderHash.new(headers) unless Hash === headers
  st = io.stat
  fileno = io.fileno
  FD_MAP[fileno] = io
  if st.file?
    headers['Content-Length'.freeze] ||= st.size.to_s
    headers.delete('Transfer-Encoding'.freeze)
  elsif st.pipe? || st.socket? # epoll-able things
    unless headers.include?('Content-Length'.freeze)
      if env['rainbows.autochunk']
        case env['HTTP_VERSION']
        when "HTTP/1.0", nil
        else
          headers['Transfer-Encoding'.freeze] = 'chunked'
        end
      else
        env['rainbows.autochunk'] = false
      end
    end

    # we need to make sure our pipe output is Fiber-compatible
    case env['rainbows.model']
    when :FiberSpawn, :FiberPool, :RevFiberSpawn, :CoolioFiberSpawn
      io.respond_to?(:kgio_wait_readable) or
        io = Rainbows::Fiber::IO.new(io)
    when :Revactor
      io = Rainbows::Revactor::Proxy.new(io)
    end
  else # unlikely, char/block device file, directory, ...
    return response
  end
  [ status, headers, Body.new(io, "/dev/fd/#{fileno}", body) ]
end