chunk unterminated HTTP/1.1 responses

Rack::Chunked will be gone in Rack 3.1, so provide a
non-middleware fallback which takes advantage of IO#write
supporting multiple arguments in Ruby 2.5+.

We still need to support Ruby 2.4, at least, since Rack 3.0
does.  So a new (GC-unfriendly) Unicorn::WriteSplat module now
exists for Ruby <= 2.4 users.

4 files changed, 51 insertions, 6 deletions

diff --git a/lib/unicorn.rb b/lib/unicorn.rb
index 1a50631..b817b77 100644
--- a/lib/unicorn.rb
+++ b/lib/unicorn.rb
@@ -66,7 +66,6 @@ module Unicorn
 
       middleware = { # order matters
         ContentLength: nil,
-        Chunked: nil,
         CommonLogger: [ $stderr ],
         ShowExceptions: nil,
         Lint: nil,
@@ -75,8 +74,8 @@ module Unicorn
 
       # return value, matches rackup defaults based on env
       # Unicorn does not support persistent connections, but Rainbows!
-      # and Zbatery both do.  Users accustomed to the Rack::Server default
-      # middlewares will need ContentLength/Chunked middlewares.
+      # does.  Users accustomed to the Rack::Server default
+      # middlewares will need ContentLength middleware.
       case ENV["RACK_ENV"]
       when "development"
       when "deployment"
diff --git a/lib/unicorn/http_response.rb b/lib/unicorn/http_response.rb
index 19469b4..0ed0ae3 100644
--- a/lib/unicorn/http_response.rb
+++ b/lib/unicorn/http_response.rb
@@ -12,6 +12,12 @@ module Unicorn::HttpResponse
 
   STATUS_CODES = defined?(Rack::Utils::HTTP_STATUS_CODES) ?
                  Rack::Utils::HTTP_STATUS_CODES : {}
+  STATUS_WITH_NO_ENTITY_BODY = defined?(
+                 Rack::Utils::STATUS_WITH_NO_ENTITY_BODY) ?
+                 Rack::Utils::STATUS_WITH_NO_ENTITY_BODY : begin
+    warn 'Rack::Utils::STATUS_WITH_NO_ENTITY_BODY missing'
+    {}
+  end
 
   # internal API, code will always be common-enough-for-even-old-Rack
   def err_response(code, response_start_sent)
@@ -35,11 +41,12 @@ module Unicorn::HttpResponse
   def http_response_write(socket, status, headers, body,
                           req = Unicorn::HttpRequest.new)
     hijack = nil
-
+    do_chunk = false
     if headers
       code = status.to_i
       msg = STATUS_CODES[code]
       start = req.response_start_sent ? ''.freeze : 'HTTP/1.1 '.freeze
+      term = STATUS_WITH_NO_ENTITY_BODY.include?(code) || false
       buf = "#{start}#{msg ? %Q(#{code} #{msg}) : status}\r\n" \
             "Date: #{httpdate}\r\n" \
             "Connection: close\r\n"
@@ -47,6 +54,12 @@ module Unicorn::HttpResponse
         case key
         when %r{\A(?:Date|Connection)\z}i
           next
+        when %r{\AContent-Length\z}i
+          append_header(buf, key, value)
+          term = true
+        when %r{\ATransfer-Encoding\z}i
+          append_header(buf, key, value)
+          term = true if /\bchunked\b/i === value # value may be Array :x
         when "rack.hijack"
           # This should only be hit under Rack >= 1.5, as this was an illegal
           # key in Rack < 1.5
@@ -55,12 +68,24 @@ module Unicorn::HttpResponse
           append_header(buf, key, value)
         end
       end
+      if !hijack && !term && req.chunkable_response?
+        do_chunk = true
+        buf << "Transfer-Encoding: chunked\r\n".freeze
+      end
       socket.write(buf << "\r\n".freeze)
     end
 
     if hijack
       req.hijacked!
       hijack.call(socket)
+    elsif do_chunk
+      begin
+        body.each do |b|
+          socket.write("#{b.bytesize.to_s(16)}\r\n", b, "\r\n".freeze)
+        end
+      ensure
+        socket.write("0\r\n\r\n".freeze)
+      end
     else
       body.each { |chunk| socket.write(chunk) }
     end
diff --git a/lib/unicorn/socket_helper.rb b/lib/unicorn/socket_helper.rb
index 8a6f6ee..c2ba75e 100644
--- a/lib/unicorn/socket_helper.rb
+++ b/lib/unicorn/socket_helper.rb
@@ -15,6 +15,20 @@ module Unicorn
     end
   end
 
+  if IO.instance_method(:write).arity == 1 # Ruby <= 2.4
+    require 'unicorn/write_splat'
+    UNIXClient = Class.new(Kgio::Socket) # :nodoc:
+    class UNIXSrv < Kgio::UNIXServer # :nodoc:
+      include Unicorn::WriteSplat
+      def kgio_tryaccept # :nodoc:
+        super(UNIXClient)
+      end
+    end
+    TCPClient.__send__(:include, Unicorn::WriteSplat)
+  else # Ruby 2.5+
+    UNIXSrv = Kgio::UNIXServer
+  end
+
   module SocketHelper
 
     # internal interface
@@ -135,7 +149,7 @@ module Unicorn
         end
         old_umask = File.umask(opt[:umask] || 0)
         begin
-          Kgio::UNIXServer.new(address)
+          UNIXSrv.new(address)
         ensure
           File.umask(old_umask)
         end
@@ -203,7 +217,7 @@ module Unicorn
         Socket.unpack_sockaddr_in(sock.getsockname)
         TCPSrv.for_fd(sock.fileno)
       rescue ArgumentError
-        Kgio::UNIXServer.for_fd(sock.fileno)
+        UNIXSrv.for_fd(sock.fileno)
       end
     end
 
diff --git a/lib/unicorn/write_splat.rb b/lib/unicorn/write_splat.rb
new file mode 100644
index 0000000..7e6e363
--- /dev/null
+++ b/lib/unicorn/write_splat.rb
@@ -0,0 +1,7 @@
+# -*- encoding: binary -*-
+# compatibility module for Ruby <= 2.4, remove when we go Ruby 2.5+
+module Unicorn::WriteSplat # :nodoc:
+  def write(*arg) # :nodoc:
+    super(arg.join(''))
+  end
+end