ResourceFu
==========

ResourceFu is a collection of hacks from various plugins that I've
developed to make using nested and polymorphic resources simpler in 
my projects.

Refactoring all of the hacks into a cohesive unit is still a 
work-in-progress so bear with me.

The first part that I've pulled in is:

Inferencing url helper methods:
===============================

Assuming this routes.rb setup:

map.resources :artists do |artist|
  artist.resources :albums do |album|
    album.resources :songs
  end
end

The standard resource helpers generated for 'albums' require that you 
always specify the artist_id:

album_path(@artist, @album)

And, if you want to have additional parameters (such as a :page number when
paginating) you can't use the positional arguments form (above) when
calling the url helper, you have to use a hash for everything:

album_path(:artist_id => @artist, :id => @album, :page => 2)

Also, the standard resource helpers fill in the route by processing your 
positional arguments from left-to-right.

album_path(@album) == album_path(:artist_id => @album) # ACK!

ResourceFu changes the way url helpers behave - and it does it in a way
that avoids costly per-request evals and/or route re-recognition.

With ResourceFu your positional arguments are 'anchored' on the right of the 
route: which means that if your route has three segments and you only supply
two positional arguments, the url helper assumes you are supplying the *last* 
two segments.

Using the above example of artists, albums and songs:

song_path(@album, @song) == song_path(:album_id => @album, :id => @song)

However, the route for song_path is still missing a critical piece of 
information, namely the artist_id.  

ResourceFu tries to 'guess' that value with a simple convention:

Any route segments that are missing are filled in by looking for instance
variables with a relevant name.  So in the example:

song_path(@album, @song)

ResourceFu will try to set the :artist_id param by first looking for an 
instance variable called @artist and then falling back to looking for an 
instance variable called @artist_id.

In album_controller.rb:

def show
  @artist_id = params[:artist_id] # or fetch the actual Artist if you want
  @album = Album.find(params[:id], :conditions => {:artist_id => @artist_id})
  @album.songs.each do |song|
    song_path(song) #=> /artists/@artist_id/albums/@album.id/songs/song.id
  end
end

Finally, if you want additional, non-route-segment params, you *don't* have
to completely switch to the hash-argument style for route helpers:

song_path(@artist, @album, @song, :page => 2, :per_page => 20)