1 files changed, 49 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
new file mode 100644
index 0000000000..2c42f4cca5
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+++ b/activerecord/lib/active_record/integration.rb
@@ -0,0 +1,49 @@
+module ActiveRecord
+  module Integration
+    # Returns a String, which Action Pack uses for constructing an URL to this
+    # object. The default implementation returns this record's id as a String,
+    # or nil if this record's unsaved.
+    #
+    # For example, suppose that you have a User model, and that you have a
+    # <tt>resources :users</tt> route. Normally, +user_path+ will
+    # construct a path with the user object's 'id' in it:
+    #
+    #   user = User.find_by_name('Phusion')
+    #   user_path(user)  # => "/users/1"
+    #
+    # You can override +to_param+ in your model to make +user_path+ construct
+    # a path using the user's name instead of the user's id:
+    #
+    #   class User < ActiveRecord::Base
+    #     def to_param  # overridden
+    #       name
+    #     end
+    #   end
+    #
+    #   user = User.find_by_name('Phusion')
+    #   user_path(user)  # => "/users/Phusion"
+    def to_param
+      # We can't use alias_method here, because method 'id' optimizes itself on the fly.
+      id && id.to_s # Be sure to stringify the id for routes
+    end
+
+    # Returns a cache key that can be used to identify this record.
+    #
+    # ==== Examples
+    #
+    #   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
+      case
+      when new_record?
+        "#{self.class.model_name.cache_key}/new"
+      when timestamp = self[:updated_at]
+        timestamp = timestamp.utc.to_s(:number)
+        "#{self.class.model_name.cache_key}/#{id}-#{timestamp}"
+      else
+        "#{self.class.model_name.cache_key}/#{id}"
+      end
+    end
+  end
+end