itrigga-cache

Adds methods to models and controllers to help caching output.

Models

With models use like below to cache the output of the block

with_cache(:key => “unique_key”) do

Model.find(:all)

end

To use a different timeout use the below. (Only supported for memcached backend. Filecache uses the value from setup!)

with_cache(:key => “unique_key”, :timeout => 42) do

Model.find(:all)

end

Controllers

With controllers use like:

with_controller_cache do

@items = Item.new_on_site(:site_id=>@current_site.id, :page=>params[:page], :per_page=>params[:per_page])

end

This will

call the block
render the content
cache the rendered output
set the :content_type according to the pasted in value (defaults to ‘text/html’)

Content-type, respond_to and response status codes

With controller caching, there are a couple of gotchas.

If you need to return a non-200 HTTP status code, set it in @status
The cached value will be the *return value* of the block
respond_to doesn’t return anything - so it can break the nice and simple pattern

So, if you’re not using an explicit render statement, you’ll need to render_to_string as the last action of your cache block:

def tracker_stats

with_controller_cache( :key=>default_cache_key ) {
  do_some_stuff_that_takes_a_long_time
  @title = "#{@client.name} Tracker Stats"
  @header = "#{@client.name} Tracker Stats"

  render_to_string # <- this will be the cached value
}

end

If you’re using respond_to, you need to do it like this:

with_controller_cache(opts) do respond_to do |format| format.html{ @content = render_to_string } format.js { @content_type = ‘text/javascript’ @content = render_to_string } end @content end

To bypass the cache just have the “freshen” => true key in the params (ie as a query string param). This will force fresh the cache

Installation

In environment.rb: config.gem ‘itrigga-cache’, :lib=>‘itrigga/cache’

In application_controller require ‘itrigga/cache’ include Itrigga::Cache Itrigga::Cache.setup!

Itrigga::Cache.setup! initializes a cache instance. Memcache and filecache are currently supported

Itrigga::Cache.setup! :backend => :memcached Options are: :servers - ip:port of the memcache instances to use :timeout - the default life of the cache item Any other options get passed to the memcached initializer - see github.com/fauna/memcached for more info

Itrigga::Cache.setup! :backend => :filecache Options are: :cache_dir - the file path to where the cache files will live :timeout - how long the cache key is valid for

Itrigga::Cache.setup! can be called as many times as you like, for as many backends as you like. The cache gem will use the last defined (setup) backend as the default backend.

Use the :backend option to force a backend with_cache(:key => “unique_key”, :backend => :memcached) do

Model.find(:all)

end

Contributing to itrigga-cache