Rails Custom RSS

I'm building an XML feed for my application and am wondering what the best way to implement it would be.

I have an Item class, with a field "related_item," which right now contains ids to related items in an array)

For instance, I could have the following item:

id: 3  
name: an item  
related_items: [67, 94, ...]

and would like to get the following xml when I access mysite.com/items/3.xml:

<item>
  <id>3</id> <name>An item</name>
  <related-items> 
    <related-item> <id>67</id> <name>A related items</name> </related-item>
    <related-item> <id>94</id> <name>Another related items</name> </related-item>
    <related-item> ... </related-item> 
  </related-items> 
</item>

What's a good way to accomplish that (this is just an example, I will actually have many more fields and would like to avoid rewriting as much as开发者_StackOverflow中文版 I can)? Thanks

See great Railscast here.

In order to avoid duplicating code, I preferred using serialization as opposed to creating a builder view. I used a little trick in order to avoid "stack too deep" problems. Here is how it look:

class Item

def to_xml(options={})
      if options[:short]
        options.merge!(:only => [:id, :name])
      else
        options.merge!(:only => [:id, :name], :include => {:related_items => {:short => true}})
      end
      super(options)
end

That way I can reuse my to_xml in other places. For instance, in my user controller I can do:

format.xml {render :xml => @user.to_xml(:include => :user_items)}

It's the best way to do it I could find.

not neccesary RSS feed is needed, but simple XML builder.. some links:

http://danengle.us/2009/05/generating-custom-xml-for-your-rails-app/

http://prograstinator.blogspot.com/2010/02/how-to-use-xml-builder-templates-in.html