Can Rails Routing Helpers (i.e. mymodel_path(model

Question

Say I have a Rails Model called Thing. Thing has a url attribute that can optionally be set to a URL somewhere on the Internet. In view code, I need logic that does the following:

<% if thing.url.blank? %>
<%= link_to('Text', thing_path(thing)) %>
<% else %>
<%= link_to('Text', thing.url) %>
<% end %>

This conditional logic in the view is ugly. Of course, I could build a helper function, which would change the view to this:

<%= thing_link('Text', thing) %>

That solves the verbosity problem, but I would really prefer having the functionality in the model itself. In which case, the view code would be:

<%= link_to('Text', thing.link) %>

This, obviously, would require a link method on the model. Here's what it would need to contain:

def link
  (self.url.blank?) ? thing_path(self) : self.url
end

To the point of the question, thing_path() is an undefined method inside Model code. I'm assuming it's possible to "pull in" some helper methods into the model, but how? And is there a real reason that routing only operates at the controller and view layers of the app? I can think of lots of cases where model code may need to deal with URLs (integrating with external systems, etc).

Answer 1

(Edit: Forget my previous babble...)

Ok, there might be situations where you would go either to the model or to some other url... But I don't really think this belongs in the model, the view (or maybe the model) sounds more apropriate.

About the routes, as far as I know the routes is for the actions in controllers (wich usually "magically" uses a view), not directly to views. The controller should handle all requests, the view should present the results and the model should handle the data and serve it to the view or controller. I've heard a lot of people here talking about routes to models (to the point I'm allmost starting to beleave it), but as I understand it: routes goes to controllers. Of course a lot of controllers are controllers for one model and is often called <modelname>sController (e.g. "UsersController" is the controller of the model "User").

If you find yourself writing nasty amounts of logic in a view, try to move the logic somewhere more appropriate; request and internal communication logic probably belongs in the controller, data related logic may be placed in the model (but not display logic, which includes link tags etc.) and logic that is purely display related would be placed in a helper.