merb-cache

A plugin for the Merb framework that provides caching

Currently supported methods:

• page caching:

• action caching

• fragment caching

• object caching

Implemented cache stores:

• memory

• memcache

• file

• database (sequel, datamapper, activerecord)

Quick intro

With fragment caching, you can mix dynamic and static content.

With action caching, the whole template is cached
but the before filters are still processed.

With page caching, the whole template is put in html files in a special
directory in order to be handled directly without triggering Merb.

Quick API

Merb::Controller class methods

cache_action(action, expiration)
cache_actions(action, [action, expiration], ...)
cache_page(action, expiration)
cache_pages(action, [action, expiration], ...)

Merb::Controller instance methods

expire_page(key)
cached_page?(key)
expire_all_pages()

expire_action(key)
cached_action?(key)

cached?(key)
cache_get(key)
cache_set(key, data, expiration)
expire(key)
expire_all()

Inside your template

cache(key, expiration) do ... end

# expiration is given in minutes

# key can be a string or a hash
# possible keys when it's a hash:
# :key (full key)
# :params (array of params to be added to the key)
# :action, :controller
# :match (true or partial key)

# Don't forget to look at the specs !!

Specs

$ rake specs:<cache_store>
example:
$ rake specs:memory
$ rake specs:file
or just:
$ cd spec
$ STORE=<cache_store> spec merb-cache_spec.rb
# cache_store can be:
#   memory, memcache, file, sequel, datamapper, activerecord

Sample configuration

Merb::Plugins.config[:merb_cache] = {
  :cache_html_directory => Merb.dir_for(:public) / "cache",

  #:store => "database",
  #:table_name => "merb_cache",

  #:disable => "development", # disable merb-cache in development
  #:disable => true, # disable merb-cache in all environments

  :store => "file",
  :cache_directory => Merb.root_path("tmp/cache"),

  #:store => "memcache",
  #:host => "127.0.0.1:11211",
  #:namespace => "merb_cache",
  #:no_tracking => false,

  #:store => "memory",
  # store could be: file, memcache, memory, database, dummy, ...
}

Quick Example

controller part

class Users < Merb::Controller
  cache_page :action_name
  # this will cache the action in public/cache/something.html
  # this cache entry will never expire (no expiration provided)
  # for permanent caching you could set your lighty/nginx so as to handle
  # the .html file directly
  # for multiple page caching:
  # cache_pages :action_name, [:another_action, 5], :some_action

  cache_action :another_action, 10
  # this will cache the action using the cache store
  # this cache entry will expire in 10 minutes
  # for multiple action caching:
  # cache_actions :action_name, [:another_action, 5], :some_action

  def list
    unless @users = cache_get("active_users")
      @users = User.all(:active => true)
      cache_set("active_users", @users)
      # object caching can be used to avoid pulling huge amounts of data
      # from the database.
      # you could have calle cache_set with an expiration time as well:
      # cache_set("active_users", @users, 10)
    end
    render
  end

  def some_action_that_invalidates_cache
    expire_page(:action_name)
    expire_action(:another_action)
    render
  end

  def delete
    expire("active_users")
    render
  end

  def archives
    @archives = User.archives unless cached?("users_archives")
    render
  end

  def index
    render
  end
end

views/users/index.html.erb

# this entry will expire in 10 minutes
<%- cache "users_index", 10 do %>
 <div>some big template</div>
<% end -%>

views/users/archive.html.erb

<%- cache "users_archives" do %>
 <div>some big template</div>
<% end -%>