Well we call them Google Sitemaps, but MSN and Yahoo are also on board and have formed sitemaps.org. So I guess we just call them XML sitemaps?

The 3 search engines currently don’t support the full sitemaps protocol, which is shame, hopefully by later this year they will.

First off : Mephisto, the Ruby on Rails blogging software that powers this site.

Creating a sitemap is no trouble at all with the Mephisto sitemap plugin. Although to get it working on this blog, I had to change the following in
vendor/plugins/mephisto_google_sitemap/lib/mephisto_google_site_map.rb from:

    def lastmod(article)
      time_zone = TimeZone.new(article.site.timezone.current_period.utc_offset)
      latest_comment = article.comments_count.zero? ? nil : article.comments.calculate(:max, :updated_at)
      (latest_comment.nil? ? article.updated_at : latest_comment).strftime("%Y-%m-%dT%H:%M:%S#{time_zone.formatted_offset}")
    end

to:

    def lastmod(article)
      latest_comment = article.comments_count.zero? ? nil : article.comments.calculate(:max, :updated_at)
      (latest_comment.nil? ? article.updated_at : latest_comment).strftime("%Y-%m-%dT%H:%M:%S+00:00")
    end

Change +00:00 to what ever your timezone offset from UTC is. Hopefully this will be fixed in a later version of the sitemap plugin.

I’m not going to make a full post on this because over on Rubyrailways.com they have an excellent post covering the main libraries for screen scraping in ruby.

However it is a bit out of date being 7 months old, and since then 2 more excellent libraries have emerged.

Hpricot from the Ruby Superstar _why which has just been updated to version 0.5 today!

And Scrapi which is also excellent.

Extracted from Mephisto is the handy plugin called permalink_fu.
This plugin allows you to use ID-less permalinks, much like that in this blog.

I wrote earlier about how to use to_param for nicer URLs, but these are even better. The plugin automatically turns a field in your model into something that could be a permalink, by stripping out all non english and non alphanumeric letters. It then saves this in a field in your database for future use.

So, onto the HowTo:

First, install the plugin in your rails app.

./script/plugin install http://svn.techno-weenie.net/projects/plugins/permalink_fu/

Now you need to add a field to your database to store the permalink.

./script/generate migration add_permalink_to_article

In the migration we add the field called permalink.

add_column :designers, :permalink, :string

Now for the model code

class Article < ActiveRecord::Base


	
title is the field name you want to convert to a permalink

        has_permalink :title
	
you can also specifiy a different permalink field in your database by giving a second paramater
	
has_permalink :title, :my_permalink_field


	
we now add the to_param method which Rails’s routing uses

        def to_param

              permalink

        end         

end

The permalink field is only populated after the record is validated, so if you have a bunch of records already in your database you can get the permalink field to populate with

Article.find(:all).each(&:save)

If you already have lots of view code written then this is the easy way to get these routes working – in your controller :

@article = Article.find_by_permalink(params[:id])

However that doesn’t seem to pass the smell test using :id rather than :permalink, but will work fine.
To use :permalink you will have to change your routing code and your view code :

# in your route file
map.connect 'article/:permalink', :controller => 'article', :action => 'view'
# in your views when linking
link_to "View #{article.title}", {:controller => 'designer', :action => 'view', :permalink => article.permalink}
# then in your controller you can use
@article = Article.find_by_permalink(params[:permalink])

Thats all! I’m always on the lookout for SEO related Rails topics to talk about so drop me a line @ questions at this domain .com.