# Shared Nested Resources **URL:** \ **Category:** Rails\ **Created:** [May 2, 2007, 7:13pm UTC](https://www.ruby-forum.com/t/shared-nested-resources/103183 "2007-05-02T19:13:47Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 2, 2007, 7:13pm UTC](https://www.ruby-forum.com/t/shared-nested-resources/103183/1 "2007-05-02T19:13:47Z")
The skinny is that I’m attempting to add “Discussions” as resources under different resources (“Groups”, “Projects”, for example) and I’ve simply hit a roadblock (or two). Discussions are an association between the “discussable” (Group, Project, etc.) and a “Topic” so: class Discussion \< ActiveRecord::Base belongs\_to :topic belongs\_to :discussable, :polymorphic =\> true end The roadblock comes about in a few places; when wanting to reference a discussion’s “discussable” for using the resource methods for pathing: discussion\_path(@discussable, @discussion). Here I did a check to see what discussable ids are present in the params. So that is solved though not as nice as I’d like. That managed to get me through the first roadblock but then I realised that now I’d have to do all sorts of logic elsewhere to determine what @discussable is and how to treat it (if its a Group or a Project, etc). I’m hoping that I’m unaware of a way of dealing with this kind of thing and that hopefully someone here can shed some light on it. However, if not, I guess I’ve got my work cut out for me. I suppose the solution would be some sort of formalized way of dealing with polymorphic resources. I’d have to devote some serious thought to that though. Any help is appreciated. Thanks. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 3, 2007, 12:36am UTC](https://www.ruby-forum.com/t/shared-nested-resources/103183/2 "2007-05-03T00:36:31Z")
> I’m hoping that I’m unaware of a way of dealing with this kind of thing > and that hopefully someone here can shed some light on it. However, if > not, I guess I’ve got my work cut out for me. I suppose the solution > would be some sort of formalized way of dealing with polymorphic > resources. I’d have to devote some serious thought to that though. In the plugin SimplyHelpful there are a number of polymorphic route methods that will soon make its way into Edge. It allows you to do polymorphic\_url(@discussable) and get group\_url(@discussable) if Group is the class of the @discussable. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 3, 2007, 4:31pm UTC](https://www.ruby-forum.com/t/shared-nested-resources/103183/3 "2007-05-03T16:31:32Z")
> In the plugin SimplyHelpful there are a number of polymorphic route > methods that will soon make its way into Edge. It allows you to do > polymorphic\_url(@discussable) and get group\_url(@discussable) if Group > is the class of the @discussable. Much appreciated, I’ll be checking that out right about now. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 3, 2007, 5:40pm UTC](https://www.ruby-forum.com/t/shared-nested-resources/103183/4 "2007-05-03T17:40:05Z")
The polymorphic\_url methods work great and are more elegant than my solution. However, there’s one final snag that I’ve run across. Beacause I’ve got two resource declarations for discussions, I am using name prefixes to avoid overwriting. Example: map.resources :projects do |projects| projects.resources :participants projects.resources :discussions, :name\_prefix =\> ‘project\_’ end map.resources :groups do |groups| groups.resources :memberships groups.resources :discussions, :name\_prefix =\> ‘group\_’ end Since all discussions are handled through my discussions controller and I can not simply use new\_discussion\_path(@discussable), I’ve defined the following as a helper: def new\_discussion\_path(discussable) case discussable.class.to\_s when ‘Project’ project\_new\_discussion\_path(discussable) ``` when 'Group' group_new_discussion_path(discussable) end ``` end (Forgive my beginner’s knowledge of the language and framework, I am doing my best to learn them thoroughly). Looking over the code for SimplyHelpful I didn’t see anything that addressed this type of scenario. Would you suggest this be best generalized into a plugin? If so, could you nudge me in a direction? I’ve never written a plugin for Rails but I am quite interested in doing so. Thanks for your time. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [May 3, 2007, 6:54pm UTC](https://www.ruby-forum.com/t/shared-nested-resources/103183/5 "2007-05-03T18:54:06Z")
Hey, The problem you’re describing is one of the reasons I created my resource\_fu plugin: [http://agilewebdevelopment.com/plugins/resource\_fu](http://agilewebdevelopment.com/plugins/resource_fu) You can see it in use in the caboose sample app: [http://blog.caboo.se/articles/2007/4/15/sample-app-gets-a-quick-bump](http://blog.caboo.se/articles/2007/4/15/sample-app-gets-a-quick-bump) The plugin takes the attitude that trying model a polymorphic relationship (“something has a discussion”) with a monomorphic controller (a single discussions controller) is a pain - you’re better off creating different controllers for each polymorph (IMHO). There’s stuff in the resource\_fu to keep things DRY and it “plays nice” with simply helpful 🙂 HTH, Trevor