Question

My controller is using the default RESTful routes for creating, adding, editing etc

I want to change the default :id to use :guuid. So what I did was:

# routes.rb
resources :posts

# Post Model
class Post < ActiveRecord::Base
    def to_param  # overridden
        guuid
    end
end

This works but my modifed REST controller code has something like this

def show
  @post = Post.find_by_guuid(params[:id])
  @title = "Review"
  respond_to do |format|
    format.html # show.html.erb
  end
end

When I see this this code ..

Post.find_by_guuid(params[:id])

it would seem wrong but it works.
I don’t understand why I can’t write it out like this:

Post.find_by_guuid(params[:guuid])

Why do I still have to pass in the params[:id] when I’m not using it?
Looking for feedback on whether my approach is correct or anything else to consider.
Even though it works it doesn’t always mean it’s right.

Answer 1

Type rake routes in your console, and check the output of the routes. You’ll see the fragment ‘:id’ in some of them, that’s where the params[:id] comes from. It’s a rails convention : when you use resources in your routes, the parameter is named id. I don’t know if you can change it (while keeping resources; otherwise you could just go with matching rules), but you shouldn’t anyway : even if it seems not very logic, it actually has sense, once your understand how rails routing works.