Rails - Sep 2005 - Cache and Unique URLs

I had a question about caching and cache sweepers. I understand that  
cache behaves much like a filter and an observer, watching actions  
and make appropriate expirations when changes occur. But when you  
have an action that is dependent on parameters derived from a URL,  
such as a date based URL. The caching mechanism misses on these  
actions. I know you can just wipe all the files using ruby''s  
delete_all method but I don''t see how to derive a pattern for this,  
when the actual edits are not made at the same URL as the cache file  
(e.g. Admin Area). And deleting all the cache files can wipe the  
performance and defeats the purpose of cache in the first place.

I don''t mean to over-complicate things but the caching functionality  
is probably one of the top features in Rails and really would like to  
get a better explanation of it beyond the Agile Book, which provides  
an excellent jumping off point and the source code isn''t quite giving  
me the info, or I''m not seeing it. I have code samples below. Thanks  
in advanced, and once I get a grip on caching I''ll do a WIKI entry  
and a post on my site about caching, because for some reason no one  
has ever touched on this there

# Sweeper Action Responsibile for Expirations; Called on Save,  
Update, and Create
     def sweep_cache(record)
         expire_page(:controller => "article",
                             :action => %w 
(:index, :category, :user, :archive, :category_archive, :user_archive),
                             :id => record.id)
# I thought this would work but it seems as thought it still misses
# I''m guessing I need to do something with IO? This Writes the path  
incorrectly anyway
## host.com/article?year=2005 blah blah blah
# Beside it couldn''t be that easy even in Ruby
         expire_page(:controller => "article/"+params[:year] 
+''/''+params[:month]+''/''+params[:day]+''/''+params[:title])
     end

# Actual Controller Actions that makes the date calls (edited for  
brevity)
   def by_date
     @article = Article.find_by_date(params[:year], params[:month],  
params[:day])
      render :action => ''index''
  end

   def permalink
       @article = Article.get_by_permalink(params[:year], params 
[:month], params[:day], params[:title])
       render :action => ''post''
   end

# Model with Queries related to Controller
     def self.find_by_date(yr, mo = nil, day = nil)
         date,tom = self.set_date(yr, mo, day)
         Article.find(:all, :conditions => [" articles.created_at  
BETWEEN ? AND ?", date, tom],
                                                     :order =>  
"articles.created_at DESC")
     end

# set_title() is a temp method to handle the stripping of non-URI  
chars (not included)
     def self.get_by_permalink(yr, mo, day, pat)
         self.find_by_date(yr, mo, day).find { |art| art.set_title 
(art.title.downcase) == pat }
     end

Thanks Again

J Brien | HybridIndie Productions | hybridindie.com |  
iam-QLwuMy0vUAhCl22TKe+ceQ@public.gmane.org
Posted Web Engine - rubyforge.org/projects/posted