Creating custom routes where a model attribute is used instead of the ID in Rails

Question

I have a model called Student, which has an attribute called University_ID in it.

I created a custom action and route which displays the details of a specific student via the following link :students/2/detailsi.e. students/:id/details

However, I want to be able to allow the user to use their university ID instead of the database ID so that the following would work for instance students/X1234521/details i.e. students/:university_id/details

My route file looks like this at the moment:

resources :students
match 'students/:id/details' => 'students#details', :as => 'details'

However this uses the Student_ID as opposed to the University_ID, and I've tried doing

match 'students/:university_id/details' => 'students#details', :as => 'details', but that only corresponds to the Student_ID, not the University_ID.

My controller looks like this, if this helps in any way:

def details
  @student = Student.find(params[:id])
end

I also tried doing @student = Student.find(params[:university_id]) but nope, nothing worked.

Answer 1

After chatting with @teenOmar to clarify the requirements, here's the solution we came up with, which allows for the existing students/:id/details route to accept either an id or a university_id (which starts with a w), and uses a before_filter to populate @student for use in various controller actions:

class StudentsController < ApplicationController

  before_filter :find_student, only: [:show, :edit, :update, :details]

  def show
    # @student will already be loaded here
    # do whatever
  end

  # same for edit, update, details

private

  def find_student
    if params[:id] =~ /^w/
      @student = Student.find_by_university_id(params[:id])
    else
      @student = Student.find(params[:id])
    end
  end

end