Sending a variable through a link_to without url query in Ruby on Rails

Question

I'm trying to send a variable through a link_to, without using url query in Ruby on Rails, from one controller's index view to be used on another controller's index.

Basically, I need to pass the Turma.id (school class id), to the Elementos_turma(peoples in the class) controller, so I can use it and filter the index: ElementosTurma.find(:all, :conditions => { :turma_id => xxxxx } ), to show the peoples of the selected class.

It it possible? Maybe without using a session variable? Maybe sending the variable to a method on the 1st controller, to send it the other controller? (if so how? not very RoR wise... :) )

Answer 1

No need for a special method to get the info you need, the magic of routes will do.

In your routes.db file, you should be able to define something like this,

map.resources :class, :has_many => :students

Then if you run 'rake routes' you should see a routes similar to this

class_students GET /classes/:class_id/students(.:format)  {:controller=>"students", :action=>"index"}

You can call that path in your view like so

class_students_path(class_id)

Then in your controller you will have access to params[:class_id]

The name of the route isn't very pretty, but this should work.

EDIT--------------------------------------

According to your comment, you can't use map.resources for some reason or another...

 map.class_students '/:class_id/students', :controller => 'students', :action => 'index'

That will produce the same route available in your view, same param in your controller.

That being said, I don't know how a server bug could prohibit you from using map.resources

Answer 2

You can not transfer data through a link without including that data in the link.

However, it sounds like you just need to be using nested resources. (Since I speak English, I'm going to not tackle another language and do what comes to me.) The URLs you want to be sending people to probably should look more like this if you want to be RESTful:

/classes/1/people/

That is the "Rails way" of indicating that you want to get people in class #1, and Rails offers built-in routing methods to make this easy. See the Rails Routing from the Outside In article in the Rails Guide.