Returns a stable cache key that can be used to identify this record.
Product.new.cache_key # => "products/new"
Product.find(5).cache_key # => "products/5"
If ActiveRecord::Base.cache_versioning is turned off, as it was in Rails 5.1 and earlier, the cache key will also include a version.
Product.cache_versioning = false
Person.find(5).cache_key # => "people/5-20071224150000" (updated_at available)
# File activerecord/lib/active_record/integration.rb, line 64 def cache_key(*timestamp_names) if new_record? "#{model_name.cache_key}/new" else if cache_version && timestamp_names.none? "#{model_name.cache_key}/#{id}" else timestamp = if timestamp_names.any? ActiveSupport::Deprecation.warn(<<-MSG.squish) Specifying a timestamp name for #cache_key has been deprecated in favor of the explicit #cache_version method that can be overwritten. MSG 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 end
Returns a cache key along with the version.
Returns a cache version that can be used together with the cache key to form a recyclable caching scheme. By default, the updated_at column is used for the #cache_version, but this method can be overwritten to return something else.
Note, this method will return nil if ActiveRecord::Base.cache_versioning is
set to false
(which it is by default until Rails 6.0).
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"