1 files changed, 52 insertions, 0 deletions
diff --git a/actionpack/lib/abstract_controller/logger.rb b/actionpack/lib/abstract_controller/logger.rb
new file mode 100644
index 0000000000..fd33bd2ddd
--- /dev/null
+++ b/actionpack/lib/abstract_controller/logger.rb
@@ -0,0 +1,52 @@
+require 'active_support/core_ext/logger'
+
+module AbstractController
+  module Logger
+    extend ActiveSupport::Concern
+
+    # A class that allows you to defer expensive processing
+    # until the logger actually tries to log. Otherwise, you are
+    # forced to do the processing in advance, and send the
+    # entire processed String to the logger, which might
+    # just discard the String if the log level is too low.
+    #
+    # TODO: Require that Rails loggers accept a block.
+    class DelayedLog
+      def initialize(&blk)
+        @blk = blk
+      end
+
+      def to_s
+        @blk.call
+      end
+      alias to_str to_s
+    end
+
+    included do
+      cattr_accessor :logger
+    end
+
+    # Override process_action in the AbstractController::Base
+    # to log details about the method.
+    def process_action(action)
+      super
+
+      if logger
+        log = DelayedLog.new do
+          "\n\nProcessing #{self.class.name}\##{action_name} " \
+          "to #{request.formats} " \
+          "(for #{request_origin}) [#{request.method.to_s.upcase}]"
+        end
+
+        logger.info(log)
+      end
+    end
+
+  private
+    def request_origin
+      # this *needs* to be cached!
+      # otherwise you'd get different results if calling it more than once
+      @request_origin ||= "#{request.remote_ip} at #{Time.now.to_s(:db)}"
+    end
+  end
+end