Replace Hash with Rack::Header/Rack::Utils::HeaderHash for Grape Headers

CHANGELOG.md

@@ -21,6 +21,7 @@
 * [#2426](https://github.com/ruby-grape/grape/pull/2426): Drop support for rack 1.x series - [@ericproulx](https://github.com/ericproulx).
 * [#2427](https://github.com/ruby-grape/grape/pull/2427): Use `rack-contrib` jsonp instead of rack-jsonp - [@ericproulx](https://github.com/ericproulx).
 * [#2363](https://github.com/ruby-grape/grape/pull/2363): Replace autoload by zeitwerk - [@ericproulx](https://github.com/ericproulx).
+* [#2425](https://github.com/ruby-grape/grape/pull/2425): Replace `{}` with `Rack::Header` or `Rack::Utils::HeaderHash` - [@dhruvCW](https://github.com/dhruvCW).
 * Your contribution here.
 
 #### Fixes

lib/grape/dsl/headers.rb

@@ -12,7 +12,7 @@ def header(key = nil, val = nil)
         if key
           val ? header[key.to_s] = val : header.delete(key.to_s)
         else
-          @header ||= {}
+          @header ||= Grape::Util::Header.new
         end
       end
       alias headers header

lib/grape/endpoint.rb

@@ -238,7 +238,7 @@ def equals?(e)
 
     def run
       ActiveSupport::Notifications.instrument('endpoint_run.grape', endpoint: self, env: env) do
-        @header = {}
+        @header = Grape::Util::Header.new
         @request = Grape::Request.new(env, build_params_with: namespace_inheritable(:build_params_with))
         @params = @request.params
         @headers = @request.headers

lib/grape/request.rb

@@ -35,7 +35,7 @@ def grape_routing_args
 
     def build_headers
       Grape::Util::Lazy::Object.new do
-        env.each_pair.with_object({}) do |(k, v), headers|
+        env.each_pair.with_object(Grape::Util::Header.new) do |(k, v), headers|
           next unless k.to_s.start_with? HTTP_PREFIX
 
           transformed_header = Grape::Http::Headers::HTTP_HEADERS[k] || transform_header(k)
@@ -44,14 +44,8 @@ def build_headers
       end
     end
 
-    if Grape::Http::Headers.lowercase?
-      def transform_header(header)
-        -header[5..].tr('_', '-').downcase
-      end
-    else
-      def transform_header(header)
-        -header[5..].split('_').map(&:capitalize).join('-')
-      end
+    def transform_header(header)
+      -header[5..].tr('_', '-').downcase
     end
   end
 end

lib/grape/util/header.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Grape
+  module Util
+    if Gem::Version.new(Rack.release) >= Gem::Version.new('3')
+      require 'rack/headers'
+      Header = Rack::Headers
+    else
+      require 'rack/utils'
+      Header = Rack::Utils::HeaderHash
+    end
+  end
+end

spec/grape/api/custom_validations_spec.rb

@@ -151,13 +151,13 @@ def validate(request)
         end
 
         def access_header
-          Grape::Http::Headers.lowercase? ? 'x-access-token' : 'X-Access-Token'
+          'x-access-token'
         end
       end
     end
 
     let(:app) { Rack::Builder.new(subject) }
-    let(:x_access_token_header) { Grape::Http::Headers.lowercase? ? 'x-access-token' : 'X-Access-Token' }
+    let(:x_access_token_header) { 'x-access-token' }
 
     before { stub_const('Grape::Validations::Validators::AdminValidator', admin_validator) }
 

spec/grape/dsl/headers_spec.rb

@@ -11,8 +11,8 @@ class Dummy
       subject { HeadersSpec::Dummy.new }
 
       let(:header_data) do
-        { 'First Key' => 'First Value',
-          'Second Key' => 'Second Value' }
+        { 'first key' => 'First Value',
+          'second key' => 'Second Value' }
       end
 
       context 'when headers are set' do
@@ -23,8 +23,8 @@ class Dummy
 
           describe 'get' do
             it 'returns a specifc value' do
-              expect(subject.header['First Key']).to eq 'First Value'
-              expect(subject.header['Second Key']).to eq 'Second Value'
+              expect(subject.header['first key']).to eq 'First Value'
+              expect(subject.header['second key']).to eq 'Second Value'
             end
 
             it 'returns all set headers' do
@@ -35,15 +35,15 @@ class Dummy
 
           describe 'set' do
             it 'returns value' do
-              expect(subject.header('Third Key', 'Third Value'))
-              expect(subject.header['Third Key']).to eq 'Third Value'
+              expect(subject.header('third key', 'Third Value'))
+              expect(subject.header['third key']).to eq 'Third Value'
             end
           end
 
           describe 'delete' do
             it 'deletes a header key-value pair' do
-              expect(subject.header('First Key')).to eq header_data['First Key']
-              expect(subject.header).not_to have_key('First Key')
+              expect(subject.header('first key')).to eq header_data['first key']
+              expect(subject.header).not_to have_key('first key')
             end
           end
         end
@@ -52,8 +52,8 @@ class Dummy
       context 'when no headers are set' do
         describe '#header' do
           it 'returns nil' do
-            expect(subject.header['First Key']).to be_nil
-            expect(subject.header('First Key')).to be_nil
+            expect(subject.header['first key']).to be_nil
+            expect(subject.header('first key')).to be_nil
           end
         end
       end

spec/grape/endpoint_spec.rb

@@ -138,23 +138,26 @@ def app
 
     it 'includes request headers' do
       get '/headers'
+      cookie_header = Grape::Http::Headers.lowercase? ? 'cookie' : 'Cookie'
+      host_header = Grape::Http::Headers.lowercase? ? 'host' : 'Host'
+
       expect(JSON.parse(last_response.body)).to include(
-        'Host' => 'example.org',
-        'Cookie' => ''
+        host_header => 'example.org',
+        cookie_header => ''
       )
     end
 
     it 'includes additional request headers' do
       get '/headers', nil, 'HTTP_X_GRAPE_CLIENT' => '1'
-      x_grape_client_header = Grape::Http::Headers.lowercase? ? 'x-grape-client' : 'X-Grape-Client'
+      x_grape_client_header = 'x-grape-client'
       expect(JSON.parse(last_response.body)[x_grape_client_header]).to eq('1')
     end
 
     it 'includes headers passed as symbols' do
       env = Rack::MockRequest.env_for('/headers')
       env[:HTTP_SYMBOL_HEADER] = 'Goliath passes symbols'
       body = read_chunks(subject.call(env)[2]).join
-      symbol_header = Grape::Http::Headers.lowercase? ? 'symbol-header' : 'Symbol-Header'
+      symbol_header = 'symbol-header'
       expect(JSON.parse(body)[symbol_header]).to eq('Goliath passes symbols')
     end
   end

spec/grape/request_spec.rb

@@ -90,7 +90,7 @@ module Grape
           }
         end
         let(:x_grape_is_cool_header) do
-          Grape::Http::Headers.lowercase? ? 'x-grape-is-cool' : 'X-Grape-Is-Cool'
+          'x-grape-is-cool'
         end
 
         it 'cuts HTTP_ prefix and capitalizes header name words' do
@@ -120,7 +120,7 @@ module Grape
           default_env.merge(request_headers)
         end
         let(:grape_likes_symbolic_header) do
-          Grape::Http::Headers.lowercase? ? 'grape-likes-symbolic' : 'Grape-Likes-Symbolic'
+          'grape-likes-symbolic'
         end
 
         it 'converts them to string' do