How to handle error when ID is not found?

Question

What is the best way to handle the error then ID is not found? I have this code in my controller:

  def show
    @match = Match.find(params[:id])
  end

I was thinking about something like this:

  def show
    if @match = Match.find(params[:id])
    else
      render 'error'
    end
  end

But I still get:

ActiveRecord::RecordNotFound in MatchesController#show

Couldn't findMatch with 'id'=2

Why?

What is the correct solution?

Answer 1

Rescue it in the base controller and leave your action code as simple as possible. You don't want to deal not found exception in every action, do you?

class ApplicationController < ActionController::Base
  rescue_from ActiveRecord::RecordNotFound, :with => :render_404

  def render_404
    render :template => "errors/error_404", :status => 404
  end
end

Answer 2

By default the find method raises an ActiveRecord::RecordNotFound exception. The correct way of handling a not found record is:

def show
  @match = Match.find(params[:id])
rescue ActiveRecord::RecordNotFound => e
  render 'error'
end

However, if you prefer an if/else approach, you can use the find_by_id method that will return nil:

def show
  @match = Match.find_by_id(params[:id])
  if @match.nil?     # or unless @match
    render 'error'
  end
end

Answer 3

You can use find_by_id method it returns nil instead of throwing exception

    Model.find_by_id