response: support auto-chunking for HTTP/1.1

We might as well do it since puma and thin both do(*),
and we can still do writev for now to get some speedups
by avoiding Rack::Chunked overhead.

timing runs of "curl --no-buffer http://127.0.0.1:9292/ >/dev/null"
results in a best case drop from ~260ms to ~205ms on one VM
by disabling Rack::Chunked in the below config.ru

$ ruby -I lib bin/yahns-rackup -E none config.ru

==> config.ru <==
class Body
  STR = ' ' * 1024 * 16
  def each
    10000.times { yield STR }
  end
end

use Rack::Chunked if ENV['RACK_CHUNKED']
run(lambda do |env|
  [ 200, [ %w(Content-Type text/plain) ], Body.new ]
end)

(*) they can do Content-Length, but I don't think it's
    worth the effort at the server level.

1 files changed, 56 insertions, 0 deletions

diff --git a/test/test_auto_chunk.rb b/test/test_auto_chunk.rb
new file mode 100644
index 0000000..a97fe26
--- /dev/null
+++ b/test/test_auto_chunk.rb
@@ -0,0 +1,56 @@
+# Copyright (C) 2013-2016 all contributors <yahns-public@yhbt.net>
+# License: GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
+# frozen_string_literal: true
+require_relative 'server_helper'
+
+class TestAutoChunk < Testcase
+  ENV["N"].to_i > 1 and parallelize_me!
+  include ServerHelper
+  alias setup server_helper_setup
+  alias teardown server_helper_teardown
+
+  def test_auto_head
+    err = @err
+    cfg = Yahns::Config.new
+    host, port = @srv.addr[3], @srv.addr[1]
+    cfg.instance_eval do
+      GTL.synchronize do
+        app = Rack::Builder.new do
+          use Rack::ContentType, "text/plain"
+          run(lambda do |env|
+            [ 200, {}, %w(a b c) ]
+          end)
+        end
+        app(:rack, app) { listen "#{host}:#{port}" }
+      end
+      logger(Logger.new(err.path))
+    end
+    pid = mkserver(cfg)
+    s = TCPSocket.new(host, port)
+    s.write("GET / HTTP/1.0\r\n\r\n")
+    assert s.wait(30), "IO wait failed"
+    buf = s.read
+    assert_match %r{\r\n\r\nabc\z}, buf
+    s.close
+
+    s = TCPSocket.new(host, port)
+    s.write("GET / HTTP/1.1\r\nHost: example.com\r\n\r\n")
+    buf = ''.dup
+    Timeout.timeout(30) do
+      until buf =~ /\r\n\r\n1\r\na\r\n1\r\nb\r\n1\r\nc\r\n0\r\n\r\n\z/
+        buf << s.readpartial(16384)
+      end
+    end
+    assert_match(%r{^Transfer-Encoding: chunked\r\n}, buf)
+    s.close
+
+    Net::HTTP.start(host, port) do |http|
+      req = Net::HTTP::Get.new("/")
+      res = http.request(req)
+      assert_equal 200, res.code.to_i
+      assert_equal 'abc', res.body
+    end
+  ensure
+    quit_wait(pid)
+  end
+end