[PATCH] remove optimizations which only made sense in old Rubies

[PATCH] remove optimizations which only made sense in old Rubies

[Eric Wong]

Constants waste memory and inline cache lookups are not free,
either.  Rely on frozen string literals in Ruby 2.3+, but continue
optimizing for opt_str_freeze in Ruby 2.1+ when literal strings are
explicitly frozen.
---
 lib/unxf.rb | 25 ++++++++-----------------
 1 file changed, 8 insertions(+), 17 deletions(-)

diff --git a/lib/unxf.rb b/lib/unxf.rb
index cf1f5e9..1f6a066 100644
--- a/lib/unxf.rb
+++ b/lib/unxf.rb
@@ -1,19 +1,10 @@
 # -*- encoding: binary -*-
+# -*- frozen_string_literal: true -*-
 require 'rpatricia'
 
 # Rack middleware to remove "HTTP_X_FORWARDED_FOR" in the Rack environment and
 # replace "REMOTE_ADDR" with the value of the original client address.
 class UnXF
-  # :stopdoc:
-  # reduce garbage overhead by using constant strings
-  REMOTE_ADDR = "REMOTE_ADDR".freeze
-  HTTP_X_FORWARDED_FOR = "HTTP_X_FORWARDED_FOR"
-  HTTP_X_FORWARDED_PROTO = "HTTP_X_FORWARDED_PROTO"
-  RACK_URL_SCHEME = "rack.url_scheme".freeze
-  UNXF_FOR = "unxf.for".freeze
-  UNXF_PROTO = "unxf.proto".freeze
-  HTTPS = "https"
-  # :startdoc:
 
   # local LAN addresses described in RFC 1918
   RFC_1918 = %w(10.0.0.0/8 172.16.0.0/12 192.168.0.0/16)
@@ -58,10 +49,10 @@ class UnXF
   # This allows existing applications to use UnXF without putting it
   # into the middleware stack (to avoid increasing stack depth and GC time)
   def unxf!(env)
-    if xff_str = env.delete(HTTP_X_FORWARDED_FOR)
-      env[UNXF_FOR] = xff_str
+    if xff_str = env.delete('HTTP_X_FORWARDED_FOR'.freeze)
+      env['unxf.for'] = xff_str
       xff = xff_str.split(/\s*,\s*/)
-      addr = env[REMOTE_ADDR]
+      addr = env['REMOTE_ADDR']
       begin
         while (/:/ =~ addr ? @trusted6 : @trusted).include?(addr) &&
               tmp = xff.pop
@@ -74,10 +65,10 @@ class UnXF
       # it's stupid to have https at any point other than the first
       # proxy in the chain, so we don't support that
       if xff.empty?
-        env[REMOTE_ADDR] = addr
-        if xfp = env.delete(HTTP_X_FORWARDED_PROTO)
-          env[UNXF_PROTO] = xfp
-          /\Ahttps\b/ =~ xfp and env[RACK_URL_SCHEME] = HTTPS
+        env['REMOTE_ADDR'] = addr
+        if xfp = env.delete('HTTP_X_FORWARDED_PROTO'.freeze)
+          env['unxf.proto'] = xfp
+          /\Ahttps\b/ =~ xfp and env['rack.url_scheme'] = 'https'.freeze
         end
       else
         return on_untrusted_addr(env, xff_str)
-- 
EW