Hi,
I’m wondering if someone can help me with this. I have a situation where I need to store information in the join model of a has_many :through to assist with genearting views. But I can’t think of an elegant and efficient solution.
Heres an example of some code:
class Mailbox < AR::B has_many :mailbox_contents has_many :postcards, :through => ‘mailbox_contents’ end
class PostCard < AR::B
has_many :mailbox_contents has_many :mailboxes, :through => ‘mailbox_contents’ end
class MailboxContent < AR::B belongs_to :mailbox belongs_to :postcard end
So then I want to be able to have a default view for the post card in each mailbox.
to do this I put a column called default_view into the MailboxContent model so that I can track default_view per postcard inside each book.
This is because users share postcards. They can exist in multiple users mailboxes, and each user may want to see the image, or the text.
I came up with the following in the controller.
def index @mailbox = Mailbox.find( :include => :mailbox_contents, :conditions => { :mailbox_id => params[:mailbox_id] } ) @postcards = @mailbox.postcards end
And then in the view
<% @postcards.each do |pc| %> View Type <%= @mailbox.mailbox_contents.find_by_postcard_id( postcard ).default_view %> <% end %>
shudder Ugly
I would like to go the other way and use something like
postcard.default_view
but I guess it would have to be postcard.default_view_for( @mailbox )
I guess the controller code would then change to
def index @mailbox = MailBox.find( paras[:id] ) @postcards = @mailbox.postcards.find( :all, :include => [:mailbox_contents] ) end
Then in the postcard model
class Postcard AR::B def default_view_for( mailbox ) self.mailbox_contents.find_by_mailbox_id( mailbox ) end end
The question is, would doing this, eager loading in the controller, then accessing the collection in the model, prevent a whole heap of db requests in the view?
I’m hoping it will since I think the mailbox_contents association should be cached for each model.
Any thoughts on a more elegant and or efficient way of doing this?
Cheers Daniel
