# Am I abusing association extensions? (AKA how would you refactor this?)

**URL:** <https://www.ruby-forum.com/t/am-i-abusing-association-extensions-aka-how-would-you-refactor-this/116349>\
**Category:** Rails\
**Created:** [October 4, 2007, 6:02pm UTC](https://www.ruby-forum.com/t/am-i-abusing-association-extensions-aka-how-would-you-refactor-this/116349 "2007-10-04T18:02:21Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Brent\_D](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/b9bd4f/32.png) [@Brent\_D](https://www.ruby-forum.com/u/Brent_D)\
**Post date:** [October 4, 2007, 6:02pm UTC](https://www.ruby-forum.com/t/am-i-abusing-association-extensions-aka-how-would-you-refactor-this/116349/1 "2007-10-04T18:02:21Z")

</div>

So I’m building a CMS for my organization with Rails, and I’m building  
it with the need to host multiple, independent sites in mind - though  
all using the same pool of models and controllers. The problem is that  
I think maybe my domain model sucks, and I’m not sure of the proper  
way to fix it.

I’ve dumped the important bits of my code into a pastie, which I’ll be  
referencing:

[http://pastie.caboo.se/103736](http://pastie.caboo.se/103736)

To summarize, a Site has\_many :sections. A Section has\_many :pages.

Eventually though, a Section may also have\_many :articles, :events,  
etc. I’m focusing on getting the static page functionality up first.

My routes.rb file has a catch-all route glob at the end:

map.connect ‘\*path’, :controller =\> ‘pages’, :action =\> ‘show’

Which hands the reigns over to the PagesController if nothing else  
catches. So the question is this: following the “skinny controller,  
fat model” mantra, with three different models involved, who does  
PagesController talk to to get the requested page?

I need to set the following in PagesController for the views:

@site (already setup by application.rb. this is fine).  
@sections (@site.sections – for top-level nav, sitemaps, etc.)  
@section (the currently viewed section)  
@pages (all the pages in the currently viewed section – for local  
nav, etc)  
@page (and of course, the currently viewed page object)

Originally, I had all of the lookup logic in page.rb. I’d do something  
like Page.find\_by\_site\_and\_path(@site, params[:path]). The problem was  
that the Page class would then have to talk to Section to get the  
appropriate @section object, and THEN figure out the page from  
@section.pages. This didn’t seem intuitive, and I felt like I had too  
much yapping going on between my models.

I then discovered association extensions and decided (to attempt) to  
refactor to what I have now, which _still_ doesn’t seem right. Instead  
of using Page to find the requested page, I’m now using the Site  
object to look it up: @site.sections.detect\_section\_and\_page via an  
association extension.

For inspiration, I looked at Mephisto, which also does a Site \>  
Sections \> Pages type deal. Its controller actually invokes a third  
party, lib/mephisto/dispatcher.rb to do all the page/article  
lookups… which seems like a round-about way to do it… but does it  
make more sense? Should I also be looking to involve a 3rd party,  
outside of my models?

Thanks to anyone who has suffered this cry for help 🙂 I hope you’ll  
have some suggestions for me.