How can you assign an event object to an event id in this example?

Question

I don't know if this a Ruby question or a Rails question but in this example of a use of nested resources in Rails, how is it possible to assign an event object to an event_id? The event object would seem to represent a larger set of values than the event_id does.

<%= link_to 'Tickets', event_tickets_path(:event_id => @event) %>

Answer 1

The following syntax should work:

event_tickets_path(@event)

Answer 2

It is a convenience built into Rails. Behind the scenes it will figure out you really just want the id. See the documentation for link_to. Here's one of its examples:

link_to "Profile", :controller => "profiles", :action => "show", :id => @profile
# => <a href="/profiles/show/1">Profile</a>

Note that something similar is being done here, and that the resulting href is using the ID.

Answer 3

In this context, Rails calls @event.to_param and returns the id attribute - to_param does this by default. You can override the to_param method in the Event Model to get it to return something other than the id.

It's not really assigning an event object to the event_id, it's assigning event.id.