Adding filter capability to ActionController logs

actionpack/CHANGELOG.md

@@ -1,4 +1,10 @@
 ## Rails 4.0.0 (unreleased) ##
+*   Add filter capability to ActionController logs for redirect locations:
+
+        config.filter_redirect << 'http://please.hide.it/'
+
+    *Fabrizio Regini*
+
 *   Fixed a bug that ignores constraints on a glob route. This was caused because the constraint
     regular expression is overwritten when the `routes.rb` file is processed. Fixes #7924
 

actionpack/lib/action_controller/metal/instrumentation.rb

@@ -60,7 +60,7 @@ def redirect_to(*args)
       ActiveSupport::Notifications.instrument("redirect_to.action_controller") do |payload|
         result = super
         payload[:status]   = response.status
-        payload[:location] = response.location
+        payload[:location] = response.filtered_location
         result
       end
     end

actionpack/lib/action_dispatch.rb

@@ -75,6 +75,7 @@ module Http
     autoload :Parameters
     autoload :ParameterFilter
     autoload :FilterParameters
+    autoload :FilterRedirect
     autoload :Upload
     autoload :UploadedFile, 'action_dispatch/http/upload'
     autoload :URL

actionpack/lib/action_dispatch/http/filter_redirect.rb

@@ -0,0 +1,37 @@
+module ActionDispatch
+  module Http
+    module FilterRedirect
+
+      FILTERED = '[FILTERED]'.freeze # :nodoc:
+
+      def filtered_location
+        if !location_filter.empty? && location_filter_match?
+          FILTERED
+        else
+          location
+        end
+      end
+
+    private
+
+      def location_filter
+        if request.present?
+          request.env['action_dispatch.redirect_filter'] || []
+        else
+          []
+        end
+      end
+
+      def location_filter_match?
+        location_filter.any? do |filter|
+          if String === filter
+            location.include?(filter)
+          elsif Regexp === filter
+            location.match(filter)
+          end
+        end
+      end
+
+    end
+  end
+end

actionpack/lib/action_dispatch/http/response.rb

@@ -61,6 +61,7 @@ class Response
     cattr_accessor(:default_headers)
 
     include Rack::Response::Helpers
+    include ActionDispatch::Http::FilterRedirect
     include ActionDispatch::Http::Cache::Response
     include MonitorMixin
 

actionpack/test/controller/log_subscriber_test.rb

@@ -26,6 +26,10 @@ def redirector
       redirect_to "http://foo.bar/"
     end
 
+    def filterable_redirector
+      redirect_to "http://secret.foo.bar/"
+    end
+
     def data_sender
       send_data "cool data", :filename => "file.txt"
     end
@@ -152,6 +156,24 @@ def test_redirect_to
     assert_equal "Redirected to http://foo.bar/", logs[1]
   end
 
+  def test_filter_redirect_url_by_string
+    @request.env['action_dispatch.redirect_filter'] = ['secret']
+    get :filterable_redirector
+    wait
+
+    assert_equal 3, logs.size
+    assert_equal "Redirected to [FILTERED]", logs[1]
+  end
+
+  def test_filter_redirect_url_by_regexp
+    @request.env['action_dispatch.redirect_filter'] = [/secret\.foo.+/]
+    get :filterable_redirector
+    wait
+
+    assert_equal 3, logs.size
+    assert_equal "Redirected to [FILTERED]", logs[1]
+  end
+
   def test_send_data
     get :data_sender
     wait

guides/source/action_controller_overview.md

@@ -751,15 +751,36 @@ Now the user can request to get a PDF version of a client just by adding ".pdf"
 GET /clients/1.pdf
 ```
 
-Parameter Filtering
--------------------
+Log Filtering
+-------------
+
+Rails keeps a log file for each environment in the `log` folder. These are extremely useful when debugging what's actually going on in your application, but in a live application you may not want every bit of information to be stored in the log file.
 
-Rails keeps a log file for each environment in the `log` folder. These are extremely useful when debugging what's actually going on in your application, but in a live application you may not want every bit of information to be stored in the log file. You can filter certain request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log.
+### Parameters Filtering
+
+You can filter certain request parameters from your log files by appending them to `config.filter_parameters` in the application configuration. These parameters will be marked [FILTERED] in the log.
 
 ```ruby
 config.filter_parameters << :password
 ```
 
+### Redirects Filtering
+
+Sometimes it's desirable to filter out from log files some sensible locations your application is redirecting to.
+You can do that by using the `config.filter_redirect` configuration option:
+
+```ruby
+config.filter_redirect << 's3.amazonaws.com'
+```
+
+You can set it to a String, a Regexp, or an array of both.
+
+```ruby
+config.filter_redirect.concat ['s3.amazonaws.com', /private_path/]
+```
+
+Matching URLs will be marked as '[FILTERED]'.
+
 Rescue
 ------
 

railties/lib/rails/application.rb

@@ -123,6 +123,7 @@ def key_generator
     # Currently stores:
     #
     #   * "action_dispatch.parameter_filter"             => config.filter_parameters
+    #   * "action_dispatch.redirect_filter"              => config.filter_redirect
     #   * "action_dispatch.secret_token"                 => config.secret_token,
     #   * "action_dispatch.show_exceptions"              => config.action_dispatch.show_exceptions
     #   * "action_dispatch.show_detailed_exceptions"     => config.consider_all_requests_local
@@ -149,6 +150,7 @@ def env_config
 
         super.merge({
           "action_dispatch.parameter_filter" => config.filter_parameters,
+          "action_dispatch.redirect_filter" => config.filter_redirect,
           "action_dispatch.secret_token" => config.secret_token,
           "action_dispatch.show_exceptions" => config.action_dispatch.show_exceptions,
           "action_dispatch.show_detailed_exceptions" => config.consider_all_requests_local,

railties/lib/rails/application/configuration.rb

@@ -13,7 +13,7 @@ class Configuration < ::Rails::Engine::Configuration
                     :railties_order, :relative_url_root, :secret_key_base, :secret_token,
                     :serve_static_assets, :ssl_options, :static_cache_control, :session_options,
                     :time_zone, :reload_classes_only_on_change,
-                    :queue, :queue_consumer, :beginning_of_week
+                    :queue, :queue_consumer, :beginning_of_week, :filter_redirect
 
       attr_writer :log_level
       attr_reader :encoding
@@ -23,6 +23,7 @@ def initialize(*)
         self.encoding = "utf-8"
         @consider_all_requests_local   = false
         @filter_parameters             = []
+        @filter_redirect               = []
         @helpers_paths                 = []
         @serve_static_assets           = true
         @static_cache_control          = nil