Enables the use of fragment caching in ActionMailer views.
Shares the cache configuration of ActionController::Base.
script/plugin install git://github.com/mikedemers/caching-mailer.git
Configure fragment caching in "config/environment.rb" (or in the configuration file for a specific environment such as "config/environments/production.rb"):
config.action_controller.perform_caching = true config.cache_store = :file_store, File.join(Rails.root, 'tmp', 'cache')
For the mailer "app/models/hello_mailer.rb":
class HelloMailer < ActionMailer::Base include_fragment_caching def hello subject "Hello, World" recipients "you@foo.com" from "me@bar.com" sent_on Time.now end end
And the template "app/views/hello_mailer/hello.text.plain.erb":
Hello, World! This is an computationally expensive list: <% cache("mail/expensive-list") do %> <% ExpensiveOperation.results.each do |result| %> * Item #<%= result.id %>: "<%= result.title %>" <% end %> <% end %>
The computationally expensive method ExpensiveOperation.results will only be invoked once. Subsequent emails will use the cached result.
For automatic expiration, try including a time value in the cache key. This example will generate a new cache entry every 2 hours (removal of stale entries is left as an exercise to the reader):
<% cache("mail/expensive-list-#{Time.now.to_i / 2.hours.to_i}") do %> <% ExpensiveOperation.results.each do |result| %> * Item #<%= result.id %>: "<%= result.title %>" <% end %> <% end %>