Update normalize_path like Rails (#2536)

* Update normalize_path like rails

* Fix cop

* Add CHANGELOG.md

* Add specs and comment

Author: ericproulx

CHANGELOG.md

@@ -5,6 +5,7 @@
 * [#2532](https://github.com/ruby-grape/grape/pull/2532): Update RuboCop 1.71.2 - [@ericproulx](https://github.com/ericproulx).
 * [#2535](https://github.com/ruby-grape/grape/pull/2535): Delegates calls to inner objects - [@ericproulx](https://github.com/ericproulx).
 * [#2537](https://github.com/ruby-grape/grape/pull/2537): Use activesupport `try` pattern - [@ericproulx](https://github.com/ericproulx).
+* [#2536](https://github.com/ruby-grape/grape/pull/2536): Update normalize_path like Rails - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 #### Fixes

lib/grape/router.rb

@@ -4,12 +4,30 @@ module Grape
   class Router
     attr_reader :map, :compiled
 
+    # Taken from Rails
+    #     normalize_path("/foo")  # => "/foo"
+    #     normalize_path("/foo/") # => "/foo"
+    #     normalize_path("foo")   # => "/foo"
+    #     normalize_path("")      # => "/"
+    #     normalize_path("/%ab")  # => "/%AB"
+    # https://github.com/rails/rails/blob/00cc4ff0259c0185fe08baadaa40e63ea2534f6e/actionpack/lib/action_dispatch/journey/router/utils.rb#L19
     def self.normalize_path(path)
+      return +'/' unless path
+
+      # Fast path for the overwhelming majority of paths that don't need to be normalized
+      return path.dup if path == '/' || (path.start_with?('/') && !(path.end_with?('/') || path.match?(%r{%|//})))
+
+      # Slow path
+      encoding = path.encoding
       path = +"/#{path}"
       path.squeeze!('/')
-      path.sub!(%r{/+\Z}, '')
-      path = '/' if path == ''
-      path
+
+      unless path == '/'
+        path.delete_suffix!('/')
+        path.gsub!(/(%[a-f0-9]{2})/) { ::Regexp.last_match(1).upcase }
+      end
+
+      path.force_encoding(encoding)
     end
 
     def initialize

spec/grape/router_spec.rb

@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+describe Grape::Router do
+  describe '.normalize_path' do
+    subject { described_class.normalize_path(path) }
+
+    context 'when no leading slash' do
+      let(:path) { 'foo%20bar%20baz' }
+
+      it { is_expected.to eq '/foo%20bar%20baz' }
+    end
+
+    context 'when path ends with slash' do
+      let(:path) { '/foo%20bar%20baz/' }
+
+      it { is_expected.to eq '/foo%20bar%20baz' }
+    end
+
+    context 'when path has recurring slashes' do
+      let(:path) { '////foo%20bar%20baz' }
+
+      it { is_expected.to eq '/foo%20bar%20baz' }
+    end
+
+    context 'when not greedy' do
+      let(:path) { '/foo%20bar%20baz' }
+
+      it { is_expected.to eq '/foo%20bar%20baz' }
+    end
+
+    context 'when encoded string in lowercase' do
+      let(:path) { '/foo%aabar%aabaz' }
+
+      it { is_expected.to eq '/foo%AAbar%AAbaz' }
+    end
+
+    context 'when nil' do
+      let(:path) { nil }
+
+      it { is_expected.to eq '/' }
+    end
+
+    context 'when empty string' do
+      let(:path) { '' }
+
+      it { is_expected.to eq '/' }
+    end
+
+    context 'when encoding is different' do
+      subject { described_class.normalize_path(path).encoding }
+
+      let(:path) { '/foo%AAbar%AAbaz'.b }
+
+      it { is_expected.to eq(Encoding::BINARY) }
+    end
+  end
+end