[PATCH 1/2] http_request: support rack.hijack by default

[PATCH 1/2] http_request: support rack.hijack by default

[Eric Wong]

Rack 1.4 and earlier will soon die out, so avoid having extra code

The only minor overhead is assigning two hash slots and
the extra hash checks when running ancient versions of Rack,
so it is unlikely anybody cares about that overhead with Rack 1.5
and later.
---
 lib/unicorn/http_request.rb | 32 +++++++++-----------------------
 1 file changed, 9 insertions(+), 23 deletions(-)

diff --git a/lib/unicorn/http_request.rb b/lib/unicorn/http_request.rb
index 9888430..b32003e 100644
--- a/lib/unicorn/http_request.rb
+++ b/lib/unicorn/http_request.rb
@@ -13,13 +13,16 @@ class Unicorn::HttpParser
     "rack.multiprocess" => true,
     "rack.multithread" => false,
     "rack.run_once" => false,
-    "rack.version" => [1, 1],
+    "rack.version" => [1, 2],
+    "rack.hijack?" => true,
     "SCRIPT_NAME" => "",
 
     # this is not in the Rack spec, but some apps may rely on it
     "SERVER_SOFTWARE" => "Unicorn #{Unicorn::Const::UNICORN_VERSION}"
   }
 
+  RACK_HIJACK = "rack.hijack".freeze
+  RACK_HIJACK_IO = "rack.hijack_io".freeze
   NULL_IO = StringIO.new("")
 
   attr_accessor :response_start_sent
@@ -98,28 +101,11 @@ class Unicorn::HttpParser
     e.merge!(DEFAULTS)
   end
 
-  # Rack 1.5.0 (protocol version 1.2) adds hijack request support
-  if ((Rack::VERSION[0] << 8) | Rack::VERSION[1]) >= 0x0102
-    DEFAULTS["rack.hijack?"] = true
-    DEFAULTS["rack.version"] = [1, 2]
-
-    RACK_HIJACK = "rack.hijack".freeze
-    RACK_HIJACK_IO = "rack.hijack_io".freeze
-
-    def hijacked?
-      env.include?(RACK_HIJACK_IO)
-    end
-
-    def hijack_setup(e, socket)
-      e[RACK_HIJACK] = proc { e[RACK_HIJACK_IO] = socket }
-    end
-  else
-    # old Rack, do nothing.
-    def hijack_setup(e, _)
-    end
+  def hijacked?
+    env.include?(RACK_HIJACK_IO)
+  end
 
-    def hijacked?
-      false
-    end
+  def hijack_setup(e, socket)
+    e[RACK_HIJACK] = proc { e[RACK_HIJACK_IO] = socket }
   end
 end
-- 
EW

[PATCH 2/2] avoid extra allocation for hijack proc creation

[Eric Wong]

proc creation is expensive, so merely use a 48-byte ivar hash slot
on the @socket ivar instead.
---
 lib/unicorn/http_request.rb | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/unicorn/http_request.rb b/lib/unicorn/http_request.rb
index b32003e..b60e383 100644
--- a/lib/unicorn/http_request.rb
+++ b/lib/unicorn/http_request.rb
@@ -97,15 +97,21 @@ class Unicorn::HttpParser
 
     e[RACK_INPUT] = 0 == content_length ?
                     NULL_IO : @@input_class.new(socket, self)
-    hijack_setup(e, socket)
+
+    # for Rack hijacking in Rack 1.5 and later
+    @socket = socket
+    e[RACK_HIJACK] = self
+
     e.merge!(DEFAULTS)
   end
 
-  def hijacked?
-    env.include?(RACK_HIJACK_IO)
+  # for rack.hijack, we respond to this method so no extra allocation
+  # of a proc object
+  def call
+    env[RACK_HIJACK_IO] = @socket
   end
 
-  def hijack_setup(e, socket)
-    e[RACK_HIJACK] = proc { e[RACK_HIJACK_IO] = socket }
+  def hijacked?
+    env.include?(RACK_HIJACK_IO)
   end
 end
-- 
EW