Good notes posted by foliosus

The docs are in the base class

Look in ActionController::Base for the docs.

You're probably looking for the docs here

ActionController::Caching::Sweeping

The docs are in AR::Base

The docs you’re looking for are in ActiveRecord::Base

Use helpers in your ActionMailer views

It’s very easy to give your mailer access to helpers:

# Let your mailer user the ApplicationHelper methods
class MyMailer < ActionMailer::Base
  helper :application
end

Use the current URL, with changes

You can use the current URL, whatever it is, with changes, as in:

# Create a link to the current page in RSS form
url_for(:overwrite_params => {:format => :rss})

This can be super-helpful because it preserves any GET params (like search parameters)