Use constants defined in ActionDispatch::Constants instead of conditional assignments

actionpack/lib/action_dispatch/http/permissions_policy.rb

@@ -21,19 +21,13 @@ module ActionDispatch # :nodoc:
   #     policy.payment     :self, "https://secure.example.com"
   #   end
   #
-  class PermissionsPolicy
-    class Middleware
   # The Feature-Policy header has been renamed to Permissions-Policy.
   # The Permissions-Policy requires a different implementation and isn't
   # yet supported by all browsers. To avoid having to rename this
   # middleware in the future we use the new name for the middleware but
   # keep the old header name and implementation for now.
-      if Gem::Version.new(Rack::RELEASE) >= Gem::Version.new("3")
-        POLICY = "feature-policy"
-      else
-        POLICY = "Feature-Policy"
-      end
-
+  class PermissionsPolicy
+    class Middleware
       def initialize(app)
         @app = app
       end
@@ -47,11 +41,11 @@ module ActionDispatch # :nodoc:
         request = ActionDispatch::Request.new(env)
 
         if policy = request.permissions_policy
-          headers[POLICY] = policy.build(request.controller_instance)
+          headers[ActionDispatch::Constants::FEATURE_POLICY] = policy.build(request.controller_instance)
         end
 
         if policy_empty?(policy)
-          headers.delete(POLICY)
+          headers.delete(ActionDispatch::Constants::FEATURE_POLICY)
         end
 
         response
@@ -65,7 +59,7 @@ module ActionDispatch # :nodoc:
         end
 
         def policy_present?(headers)
-          headers[POLICY]
+          headers[ActionDispatch::Constants::FEATURE_POLICY]
         end
 
         def policy_empty?(policy)

actionpack/lib/action_dispatch/http/response.rb

@@ -38,14 +38,10 @@ module ActionDispatch # :nodoc:
       # For `Rack::Headers` (Rack 3+):
       require "rack/headers"
       Headers = ::Rack::Headers
-
-      LOCATION = "location"
     rescue LoadError
       # For `Rack::Utils::HeaderHash`:
       require "rack/utils"
       Headers = ::Rack::Utils::HeaderHash
-
-      LOCATION = "Location"
     end
 
     # To be deprecated:

actionpack/lib/action_dispatch/middleware/actionable_exceptions.rb

@@ -38,7 +38,7 @@ module ActionDispatch
         [302, {
           Rack::CONTENT_TYPE => "text/html; charset=#{Response.default_charset}",
           Rack::CONTENT_LENGTH => body.bytesize.to_s,
-          ActionDispatch::Response::LOCATION => location,
+          ActionDispatch::Constants::LOCATION => location,
         }, [body]]
       end
   end

actionpack/lib/action_dispatch/middleware/static.rb

@@ -50,14 +50,6 @@ module ActionDispatch
       "identity" => nil
     }
 
-    if Gem::Version.new(Rack::RELEASE) < Gem::Version.new("3")
-      VARY = "Vary"
-      CONTENT_ENCODING = "Content-Encoding"
-    else
-      VARY = "vary"
-      CONTENT_ENCODING = "content-encoding"
-    end
-
     def initialize(root, index: "index", headers: {}, precompressed: %i[ br gzip ], compressible_content_types: /\A(?:text\/|application\/javascript)/)
       @root = root.chomp("/").b
       @index = index
@@ -136,10 +128,10 @@ module ActionDispatch
             if content_encoding == "identity"
               return precompressed_filepath, headers
             else
-              headers[VARY] = "accept-encoding"
+              headers[ActionDispatch::Constants::VARY] = "accept-encoding"
 
               if accept_encoding.any? { |enc, _| /\b#{content_encoding}\b/i.match?(enc) }
-                headers[CONTENT_ENCODING] = content_encoding
+                headers[ActionDispatch::Constants::CONTENT_ENCODING] = content_encoding
                 return precompressed_filepath, headers
               end
             end

actionpack/test/dispatch/permissions_policy_test.rb

@@ -76,7 +76,7 @@ class PermissionsPolicyMiddlewareTest < ActionDispatch::IntegrationTest
 
     get "/index"
 
-    assert_equal "gyroscope 'self'", response.headers[ActionDispatch::PermissionsPolicy::Middleware::POLICY]
+    assert_equal "gyroscope 'self'", response.headers[ActionDispatch::Constants::FEATURE_POLICY]
   end
 
   test "non-html requests will not set a policy" do
@@ -84,15 +84,15 @@ class PermissionsPolicyMiddlewareTest < ActionDispatch::IntegrationTest
 
     get "/index"
 
-    assert_nil response.headers[ActionDispatch::PermissionsPolicy::Middleware::POLICY]
+    assert_nil response.headers[ActionDispatch::Constants::FEATURE_POLICY]
   end
 
   test "existing policies will not be overwritten" do
-    @app = build_app(->(env) { [200, { ActionDispatch::PermissionsPolicy::Middleware::POLICY => "gyroscope 'none'" }, []] })
+    @app = build_app(->(env) { [200, { ActionDispatch::Constants::FEATURE_POLICY => "gyroscope 'none'" }, []] })
 
     get "/index"
 
-    assert_equal "gyroscope 'none'", response.headers[ActionDispatch::PermissionsPolicy::Middleware::POLICY]
+    assert_equal "gyroscope 'none'", response.headers[ActionDispatch::Constants::FEATURE_POLICY]
   end
 
   private
@@ -289,6 +289,6 @@ class PermissionsPolicyWithHelpersIntegrationTest < ActionDispatch::IntegrationT
 
     def assert_policy(expected)
       assert_response :success
-      assert_equal expected, response.headers["Feature-Policy"]
+      assert_equal expected, response.headers[ActionDispatch::Constants::FEATURE_POLICY]
     end
 end

railties/test/application/permissions_policy_test.rb

@@ -5,7 +5,7 @@ require "rack/test"
 
 module ApplicationTests
   class PermissionsPolicyTest < ActiveSupport::TestCase
-    POLICY = ActionDispatch::PermissionsPolicy::Middleware::POLICY
+    POLICY = ActionDispatch::Constants::FEATURE_POLICY
 
     include ActiveSupport::Testing::Isolation
     include Rack::Test::Methods