Rails Custom Error Page Working and Not Working - ruby-on-rails-4

Question

ruby-2.3.7 Rails 5.1.4
I'm trying to learn about error pages in Rails apps: how to create them and how they get called/triggered. I've read quite a few posts and blogs about this. I've found several that use the same approach. It seems simple enough, so I tried to implement it.
When I go directly to my new 404 or 500 page: ...myapp/404 or ...myapp/500 I get the correct custom 404/500 page. But when I trigger a different 500 error, I do not. I.e: ...myapp.employee/99999 throws an error because there is no such employee:
500 Internal Server Error
If you are the administrator of this website, then please read this web application's log file and/or the web server's log file to find out what went wrong
How do I get errors to go to my new error pages?
Code:
config/environments/development.rb:
-------
# see error pages in dev site
config.consider_all_requests_local = false # true
config/application.rb:
-------
# added for error pages
config.exceptions_app = self.routes
config/routes.rb
------
get "/404", to: "errors#not_found", :via => :all
get "/500", to: "errors#internal_server_error", :via => :all
controllers/errors_controller.rb
-----
class ErrorsController < ApplicationController
def not_found
respond_to do |format|
format.html { render status: 404 }
end
end
def internal_server_error
respond_to do |format|
format.html { render status: 500 }
end
end
end
---> these work so I wont paste the content here.
app/views/errors/not_found.html.erb
app/views/errors/internal_server_error.html.erb
Is this the right approach? If Yes, what am I missing or not understanding.
Thanks for any help.

Answer 1

You need to add these in your top level (application) controller and rescue accordingly. Some sample code from a project I'm working on:
rescue_from ActiveRecord::RecordNotFound do |e|
puts "#{e.inspect}, PARAMS: #{params.inspect}" if Config[:verbose_tests]
respond_with_404
end
rescue_from ActionController::RoutingError do |e|
puts "#{e.inspect}, PARAMS: #{params.inspect}" if Config[:verbose_tests]
respond_with_404
end
rescue_from Pundit::NotAuthorizedError do
respond_with_403
end
In your case, this would be something like:
// app/controllers/application_controller.rb
rescue_from ActiveRecord::RecordNotFound do
not_found
end
rescue_from ActionController::RoutingError do
not_found
end
rescue_from ActionController::StandardError do
internal_server_error
end
Make sure you have access to your internal_server_error and not_found methods inside your application controller, you can even define them there, and then when the error is thrown your app should respond accordingly.