Make stringify_keys use transform_keys

2 files changed, 23 insertions, 5 deletions

diff --git a/lib/rack/core_ext/hash.rb b/lib/rack/core_ext/hash.rb
new file mode 100644
index 00000000..f86a3611
--- /dev/null
+++ b/lib/rack/core_ext/hash.rb
@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+# Hash has `transform_keys` since Ruby 2.5.
+# For Ruby < 2.5, we need to add the following
+
+module Rack
+  module HashExtensions
+    refine Hash do
+      def transform_keys(&block)
+        hash = {}
+        each do |key, value|
+          hash[block.call(key)] = value
+        end
+        hash
+      end unless {}.respond_to?(:transform_keys)
+    end
+  end
+end
+
diff --git a/lib/rack/session/abstract/id.rb b/lib/rack/session/abstract/id.rb
index c9f9f458..69dafe78 100644
--- a/lib/rack/session/abstract/id.rb
+++ b/lib/rack/session/abstract/id.rb
@@ -9,6 +9,8 @@ require 'rack/request'
 require 'rack/response'
 require 'securerandom'
 
+require_relative '../../core_ext/hash'
+
 module Rack
 
   module Session
@@ -17,6 +19,7 @@ module Rack
       # SessionHash is responsible to lazily load the session from store.
 
       class SessionHash
+        using ::Rack::HashExtensions
         include Enumerable
         attr_writer :id
 
@@ -162,11 +165,7 @@ module Rack
         end
 
         def stringify_keys(other)
-          hash = {}
-          other.each do |key, value|
-            hash[key.to_s] = value
-          end
-          hash
+          other.transform_keys(&:to_s)
         end
       end