# Acces to restfull route paths in models

**URL:** <https://www.ruby-forum.com/t/acces-to-restfull-route-paths-in-models/92261>\
**Category:** Rails\
**Created:** [April 17, 2007, 5:08pm UTC](https://www.ruby-forum.com/t/acces-to-restfull-route-paths-in-models/92261 "2007-04-17T17:08:33Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![temesta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/e9bcb4/32.png) [@temesta](https://www.ruby-forum.com/u/temesta)\
**Post date:** [April 17, 2007, 5:08pm UTC](https://www.ruby-forum.com/t/acces-to-restfull-route-paths-in-models/92261/1 "2007-04-17T17:08:33Z")

</div>

Hello,

I’m not sure wether this has already been asked on this forum. I’m  
trying to create a method in my model which returns a path/url. It seems  
like I can’t have acces to the restfull routing system from my models.

Here is my model:

class Componentgroup \< ActiveRecord::Base

```
acts_as_tree :order => "name"

def getPage
    self.root.pageresource.page
end

def getLinkToParent
    if self.root == self
        pageresources_path getPage
    else
        groupresources_path self.parent
    end
end

```

end

getLinkToParent returns this ugly error:

undefined method `pageresources\_path’ for #Componentgroup:0x48b6664

Any ideas for a workaround are welcome.

---

<div class="post-metadata">

**Author:** ![temesta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/e9bcb4/32.png) [@temesta](https://www.ruby-forum.com/u/temesta)\
**Post date:** [April 17, 2007, 5:54pm UTC](https://www.ruby-forum.com/t/acces-to-restfull-route-paths-in-models/92261/2 "2007-04-17T17:54:47Z")

</div>

You are not allowed to access controller-related stuff in the models. It  
violates MVC. You will find that you can’t access sessions, request  
parameters, or other things back there.

You may want to use your models without using your controllers, like  
for  
backend stuff. You might need a whole new controller layer at some  
point,  
instead of the HTML-based one (like flex maybe, so restful routing isn’t  
an  
issue.

I recommend making a helper that takes the model as a parameter.

If there’s a specific reason you need to have that information in there,  
you  
can hack around it by including the appropriate modules in your model  
class.  
A purist would find this ugly… if you’re hitting a wall with MVC, it  
might  
be because you’re trying to do something you shouldn’t. (That’s not  
always  
true… there are valid reasons for violating MVC, but they are rare.)

Maybe you could explain in more detail the feature you’re trying to  
implement, and someone could come up with an alternative solution for  
you.

Good luck!

---

<div class="post-metadata">

**Author:** ![temesta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/e9bcb4/32.png) [@temesta](https://www.ruby-forum.com/u/temesta)\
**Post date:** [April 17, 2007, 8:00pm UTC](https://www.ruby-forum.com/t/acces-to-restfull-route-paths-in-models/92261/3 "2007-04-17T20:00:50Z")

</div>

Thanks for the information. I guess you’re right that I’m violating MVC  
principles so there must be a better solution. I was already thinking  
about a helper module but I seems to be a bit of overkill for this tiny  
little method. Anyway,

I’m building a little component based content management system. Each  
site consists of pages, a page consists of single components and/or  
componentgroups.

Each componentgroup consists of single components or other  
componentgroups. So componentgroups can be nested deeply. That’s why I  
defined “acts\_as\_tree” in the componentgroup model.

The structure of a website would look like this:

-\> site  
-\> page  
-\> component  
-\> component  
-\> componentgroup 1  
-\> component  
-\> componentgroup 2  
-\> component  
-\> component  
-\> other page  
…

```
def getLinkToParent
    if self.root == self
        pageresources_path getPage
    else
        groupresources_path self.parent
    end
end

```

The “getLinkToParent” method generates the proper URL to a lower level.  
So if a user is viewing “componentgroup 2” child resources/components,  
he needs a “back” link to the resources of “componentgroup 1”. In this  
case the parent of componentgroup 2 is also a componentgroup. The method  
will therefore redirect the user to “groupresources\_path self.parent”.  
BUT if the user is at the level of “componentgroup 1” (= root of tree),  
he needs to be redirected to page level for viewing all child resources  
of a page.

So I wanted an elegant solution for creating a back link when viewing  
the list of components contained in a componentgroup. Something like  
this:

\<%= link\_to ‘Back’, @componentgroup.getLinkToParent %\>

I hope this makes any sense :). It’s not easy to make a an abstraction  
of the whole thing 🙂 Maby this is also a good time to discuss my  
concept?

---

<div class="post-metadata">

**Author:** ![temesta](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/e9bcb4/32.png) [@temesta](https://www.ruby-forum.com/u/temesta)\
**Post date:** [April 19, 2007, 3:55pm UTC](https://www.ruby-forum.com/t/acces-to-restfull-route-paths-in-models/92261/4 "2007-04-19T15:55:56Z")

</div>

No, you’re on the right track…

helper method should work fine. In your view, you’d do this:

\<%=link\_to “back”, parent\_link\_url(@componentgroup) %\>

# determines the parent link.

def parent\_link\_url(component)  
component.root == component ? pageresources\_path component :  
groupresources\_path self.parent  
end

Let me know if that’s gonna work for you.