Ryan's Scraps

It appears that Rails controller will no longer be limited to file-based page and fragment caching. There is a lot of work being done in the 2-1-caching branch of Rails that will let you specify your preferred caching engine in the config file. To date there are the following options:

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ActionController::Base.cache_store = :memory_store
ActionController::Base.cache_store = :file_store, "/path/to/cache/directory"
ActionController::Base.cache_store = :drb_store, "druby://localhost:9192"
ActionController::Base.cache_store = :mem_cache_store, "localhost"

If none is specified, then ActiveSupport::Cache::MemoryStore will be used.

Write Your Own Controller Cache

Interested in writing your own controller caching mechanism? Here are some basic steps:

1. Implement the Cache Class

The easiest way to write your own cache class is to subclass ActiveSupport::Cache::Store and implement the read, write, delete and delete_matched methods:

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module ActiveSupport
  module Cache

    # Pluck and store stuff in the ether.
    # ('Ether' is fictitious - ignore its implementation)
    class EtherStore < Store

      def initialize(location='//myloc')
        @ether = Ether.new(location)
      end

      def read(name, options = nil)
        super
        @ether.get(name)
      end

      def write(name, value, options = nil)
        super
        @ether.store(name, value)
      end

      def delete(name, options = nil)
        super
        @ether.remove(name)
      end
        
      def delete_matched(matcher, options = nil)
        super
        @ether.remove_by_pattern(matcher)
      end
    end
  end
end

• Invoking super for each method call ensures that the proper messages get logged for each action
• If the underlying cache mechanism doesn’t support a specific operation (such as delete_matched), have your implementation just raise an exception: raise "delete_matched not supported by Mechanism"
• The options argument passed to each method is taken directly from the various top-level cache methods which now accept an options hash (you now have a method to pass in options applicable to your caching mechanism). I.e.in your view when fragment caching:

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<% cache('name', :expires_in => 60) do %>
  <%= render :partial => "menu" %>
<% end %>

2. Plug-in Cache

Once you have your implementation (and it’s tested, of course), plug it into your app with a simple one-liner in environment.rb:

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# Or EtherStore.new('//etherloc')
ActionController::Base.cache_store = :ether_store, '//etherloc'

There you go, that’s all there is to it.

I’m not sure what the intent is for this functionality, but as of now it only exists in the 2-1-caching branch of rails, I will update this post when it makes it to edge.

tags: ruby, rubyonrails

It appears that, after a short release candidate period, Rails 2.0 (.1) final has now been released. In celebration of such an event, I’ve compiled a list of all the features of Rails 2 that I’ve written about so far. Soak it in, baby.

Though I’ve made my best effort to keep all the feature descriptions up-to-date, I can’t guarantee their complete accuracy. For a more exhaustively and thoroughly vetted list of features presented in a more refined manner you may just have to suck it up and buy the Peepcode min-book PDF on Rails 2. “It’s good stuff”, says the author!

Major Rails 2 Features and Changes

(sorted by date added)

• ActionMailer::Base.server_settings Deprecated
• 1.month.from_now.no_longer.effed
• Source Code Annotations
• A Better Way to Access Your Helpers
• Stop Littering In Your Environment File
• ActiveRecord Caching Provided in Actions
• Cookie Based Sessions are the New Default
• Expanded Caching Scope
• .rhtml and .rxml to Die a Slow and Painful Death
• Mime::Type Convenience Methods
• ActiveRecord Explicit Caching
• RESTful Routes Get a New Custom Delimiter
• Object Transactions Are Out
• ActiveResource Gets Custom Methods
• render Now 70% More Betterer
• A More Flexible to_xml
• New Database Rake Tasks
• validates_numericality_of Gets Pimped
• ActiveResource Finder Update and Custom Headers
• RESTful Routing Updates
• Bringin’ Sexy Back
• No More (conventional) Pagination
• Collection Fixtures
• Use Rake to List Your Routes
• Partials Get Layouts
• Your DB Adapter May Have Left the Building
• Logging Gets a Little Snappier
• Better Cross-Site Request Forging Prevention
• Better Exception Handling
• Specify Plugin Load Ordering
• Validations Now :allow_blank
• Fixtures Just Got a Whole Lot Easier
• Filters get Tweaked
• Pre-Environment Load Hook

For another great feature overview, check out the official rails blog announcement.

Anybody ready for Rails 3?

tags: ruby, rubyonrails