1 files changed, 54 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
index 2589b2f3da..31e2518540 100644
--- a/activerecord/lib/active_record/integration.rb
+++ b/activerecord/lib/active_record/integration.rb
@@ -1,3 +1,5 @@
+require 'active_support/core_ext/string/filters'
+
 module ActiveRecord
   module Integration
     extend ActiveSupport::Concern
@@ -45,10 +47,19 @@ module ActiveRecord
     #   Product.new.cache_key     # => "products/new"
     #   Product.find(5).cache_key # => "products/5" (updated_at not available)
     #   Person.find(5).cache_key  # => "people/5-20071224150000" (updated_at available)
-    def cache_key
+    #
+    # You can also pass a list of named timestamps, and the newest in the list will be
+    # used to generate the key:
+    #
+    #   Person.find(5).cache_key(:updated_at, :last_reviewed_at)
+    def cache_key(*timestamp_names)
       case
       when new_record?
         "#{self.class.model_name.cache_key}/new"
+      when timestamp_names.any?
+        timestamp = max_updated_column_timestamp(timestamp_names)
+        timestamp = timestamp.utc.to_s(cache_timestamp_format)
+        "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
       when timestamp = max_updated_column_timestamp
         timestamp = timestamp.utc.to_s(cache_timestamp_format)
         "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
@@ -56,5 +67,47 @@ module ActiveRecord
         "#{self.class.model_name.cache_key}/#{id}"
       end
     end
+
+    module ClassMethods
+      # Defines your model's +to_param+ method to generate "pretty" URLs
+      # using +method_name+, which can be any attribute or method that
+      # responds to +to_s+.
+      #
+      #   class User < ActiveRecord::Base
+      #     to_param :name
+      #   end
+      #
+      #   user = User.find_by(name: 'Fancy Pants')
+      #   user.id         # => 123
+      #   user_path(user) # => "/users/123-fancy-pants"
+      #
+      # Values longer than 20 characters will be truncated. The value
+      # is truncated word by word.
+      #
+      #   user = User.find_by(name: 'David HeinemeierHansson')
+      #   user.id         # => 125
+      #   user_path(user) # => "/users/125-david"
+      #
+      # Because the generated param begins with the record's +id+, it is
+      # suitable for passing to +find+. In a controller, for example:
+      #
+      #   params[:id]               # => "123-fancy-pants"
+      #   User.find(params[:id]).id # => 123
+      def to_param(method_name = nil)
+        if method_name.nil?
+          super()
+        else
+          define_method :to_param do
+            if (default = super()) &&
+                 (result = send(method_name).to_s).present? &&
+                   (param = result.squish.truncate(20, separator: /\s/, omission: nil).parameterize).present?
+              "#{default}-#{param}"
+            else
+              default
+            end
+          end
+        end
+      end
+    end
   end
 end