1 files changed, 55 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/messages/metadata.rb b/activesupport/lib/active_support/messages/metadata.rb
new file mode 100644
index 0000000000..db14ac0b1c
--- /dev/null
+++ b/activesupport/lib/active_support/messages/metadata.rb
@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+require "time"
+
+module ActiveSupport
+  module Messages #:nodoc:
+    class Metadata #:nodoc:
+      def initialize(expires_at, purpose)
+        @expires_at, @purpose = expires_at, purpose.to_s
+      end
+
+      class << self
+        def wrap(message, expires_at: nil, expires_in: nil, purpose: nil)
+          if expires_at || expires_in || purpose
+            { "value" => message, "_rails" => { "exp" => pick_expiry(expires_at, expires_in), "pur" => purpose } }
+          else
+            message
+          end
+        end
+
+        def verify(message, purpose)
+          metadata = extract_metadata(message)
+
+          if metadata.nil?
+            message if purpose.nil?
+          elsif metadata.match?(purpose) && metadata.fresh?
+            message["value"]
+          end
+        end
+
+        private
+          def pick_expiry(expires_at, expires_in)
+            if expires_at
+              expires_at.utc.iso8601(3)
+            elsif expires_in
+              Time.now.utc.advance(seconds: expires_in).iso8601(3)
+            end
+          end
+
+          def extract_metadata(message)
+            if message.is_a?(Hash) && message.key?("_rails")
+              new(message["_rails"]["exp"], message["_rails"]["pur"])
+            end
+          end
+      end
+
+      def match?(purpose)
+        @purpose == purpose.to_s
+      end
+
+      def fresh?
+        @expires_at.nil? || Time.now.utc < Time.iso8601(@expires_at)
+      end
+    end
+  end
+end