# module ActiveRecord::Integration

### Public Instance Methods

cache_key(*timestamp_names) click to toggle source

Returns a cache key that can be used to identify this record.

    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)

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)

    # File lib/active_record/integration.rb, line 55
    def cache_key(*timestamp_names)
      if new_record?
        "#{model_name.cache_key}/new"
      else
        timestamp = if timestamp_names.any?
          max_updated_column_timestamp(timestamp_names)
        else
          max_updated_column_timestamp
        end

        if timestamp
          timestamp = timestamp.utc.to_s(cache_timestamp_format)
          "#{model_name.cache_key}/#{id}-#{timestamp}"
        else
          "#{model_name.cache_key}/#{id}"
        end
      end
    end

to_param() click to toggle source

Returns a `String`, which Action Pack uses for constructing a 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 `resources :users` 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"

    # File lib/active_record/integration.rb, line 40
    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